diff --git gcc/config/nds32/nds32.c gcc/config/nds32/nds32.c
new file mode 100644
index 0000000..a1db7e5
--- /dev/null
+++ gcc/config/nds32/nds32.c
@@ -0,0 +1,5417 @@
+/* Subroutines used for code generation of Andes NDS32 cpu for GNU compiler
+   Copyright (C) 2012-2013 Free Software Foundation, Inc.
+   Contributed by Andes Technology Corporation.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 3, or (at your
+   option) any later version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "rtl.h"
+#include "regs.h"
+#include "hard-reg-set.h"
+#include "insn-config.h"	/* Required by recog.h.  */
+#include "conditions.h"
+#include "output.h"
+#include "insn-attr.h"		/* For DFA state_t.  */
+#include "insn-codes.h"		/* For CODE_FOR_xxx.  */
+#include "reload.h"		/* For push_reload().  */
+#include "flags.h"
+#include "function.h"
+#include "expr.h"
+#include "recog.h"
+#include "diagnostic-core.h"
+#include "df.h"
+#include "tm_p.h"
+#include "tm-constrs.h"
+#include "optabs.h"		/* For GEN_FCN.  */
+#include "target.h"
+#include "target-def.h"
+#include "langhooks.h"		/* For add_builtin_function().  */
+#include "ggc.h"
+
+/* ------------------------------------------------------------------------ */
+
+/* This file is divided into six parts:
+
+     PART 1: Auxiliary static variable definitions and
+             target hook static variable definitions.
+
+     PART 2: Auxiliary static function definitions.
+
+     PART 3: Implement target hook stuff definitions.
+
+     PART 4: Implemet extern function definitions,
+             the prototype is in nds32-protos.h.
+
+     PART 5: Initialize target hook structure and definitions.  */
+
+/* ------------------------------------------------------------------------ */
+
+/* PART 1: Auxiliary static variable definitions and
+           target hook static variable definitions.  */
+
+/* Refer to nds32.h, there are maximum 73 isr vectors in nds32 architecture.
+   0 for reset handler with __attribute__((reset())),
+   1-8 for exception handler with __attribute__((exception(1,...,8))),
+   and 9-72 for interrupt handler with __attribute__((interrupt(0,...,63))).
+   We use an array to record essential information for each vector.  */
+static struct nds32_isr_info nds32_isr_vectors[NDS32_N_ISR_VECTORS];
+
+/* Define intrinsic register names.
+   Please refer to nds32_intrinsic.h file, the index is corresponding to
+   'enum nds32_intrinsic_registers' data type values.
+   NOTE that the base value starting from 1024.  */
+static const char * const nds32_intrinsic_register_names[] =
+{
+  "$PSW", "$IPSW", "$ITYPE", "$IPC"
+};
+
+/* Defining target-specific uses of __attribute__.  */
+static const struct attribute_spec nds32_attribute_table[] =
+{
+  /* Syntax: { name, min_len, max_len, decl_required, type_required,
+               function_type_required, handler, affects_type_identity } */
+
+  /* The interrupt vid: [0-63]+ (actual vector number starts from 9 to 72).  */
+  { "interrupt",    1, 64, false, false, false, NULL, false },
+  /* The exception vid: [1-8]+  (actual vector number starts from 1 to 8).  */
+  { "exception",    1,  8, false, false, false, NULL, false },
+  /* Argument is user's interrupt numbers.  The vector number is always 0.  */
+  { "reset",        1,  1, false, false, false, NULL, false },
+
+  /* The attributes describing isr nested type.  */
+  { "nested",       0,  0, false, false, false, NULL, false },
+  { "not_nested",   0,  0, false, false, false, NULL, false },
+  { "nested_ready", 0,  0, false, false, false, NULL, false },
+
+  /* The attributes describing isr register save scheme.  */
+  { "save_all",     0,  0, false, false, false, NULL, false },
+  { "partial_save", 0,  0, false, false, false, NULL, false },
+
+  /* The attributes used by reset attribute.  */
+  { "nmi",          1,  1, false, false, false, NULL, false },
+  { "warm",         1,  1, false, false, false, NULL, false },
+
+  /* The attribute telling no prologue/epilogue.  */
+  { "naked",        0,  0, false, false, false, NULL, false },
+
+  /* The last attribute spec is set to be NULL.  */
+  { NULL,           0,  0, false, false, false, NULL, false }
+};
+
+
+/* ------------------------------------------------------------------------ */
+
+/* PART 2: Auxiliary static function definitions.  */
+
+/* Function to save and restore machine-specific function data.  */
+static struct machine_function *
+nds32_init_machine_status (void)
+{
+  struct machine_function *machine;
+  machine = ggc_alloc_cleared_machine_function ();
+
+  /* Initially assume this function needs prologue/epilogue.  */
+  machine->naked_p = 0;
+
+  /* Initially assume this function does NOT use fp_as_gp optimization.  */
+  machine->fp_as_gp_p = 0;
+
+  return machine;
+}
+
+/* Function to compute stack frame size and
+   store into cfun->machine structure.  */
+static void
+nds32_compute_stack_frame (void)
+{
+  int r;
+  int block_size;
+
+  /* Before computing everything for stack frame size,
+     we check if it is still worth to use fp_as_gp optimization.
+     If it is, the 'df_regs_ever_live_p (FP_REGNUM)' will be set
+     so that $fp will be saved on stack.  */
+  cfun->machine->fp_as_gp_p = nds32_fp_as_gp_check_available ();
+
+  /* Because nds32_compute_stack_frame() will be called from different place,
+     everytime we enter this function, we have to assume this function
+     needs prologue/epilogue.  */
+  cfun->machine->naked_p = 0;
+
+  /* Get variadic arguments size to prepare pretend arguments and
+     push them into stack at prologue.
+     Currently, we do not push variadic arguments by ourself.
+     We have GCC handle all the works.
+     The caller will push all corresponding nameless arguments into stack,
+     and the callee is able to retrieve them without problems.
+     These variables are still preserved in case one day
+     we would like caller passing arguments with registers.  */
+  cfun->machine->va_args_size = 0;
+  cfun->machine->va_args_first_regno = SP_REGNUM;
+  cfun->machine->va_args_last_regno  = SP_REGNUM;
+
+  /* Get local variables, incoming variables, and temporary variables size.
+     Note that we need to make sure it is 8-byte alignment because
+     there may be no padding bytes if we are using LRA.  */
+  cfun->machine->local_size = NDS32_ROUND_UP_DOUBLE_WORD (get_frame_size ());
+
+  /* Get outgoing arguments size.  */
+  cfun->machine->out_args_size = crtl->outgoing_args_size;
+
+  /* If $fp value is required to be saved on stack, it needs 4 bytes space.
+     Check whether $fp is ever live.  */
+  cfun->machine->fp_size = (df_regs_ever_live_p (FP_REGNUM)) ? 4 : 0;
+
+  /* If $gp value is required to be saved on stack, it needs 4 bytes space.
+     Check whether we are using PIC code genration.  */
+  cfun->machine->gp_size = (flag_pic) ? 4 : 0;
+
+  /* If $lp value is required to be saved on stack, it needs 4 bytes space.
+     Check whether $lp is ever live.  */
+  cfun->machine->lp_size = (df_regs_ever_live_p (LP_REGNUM)) ? 4 : 0;
+
+  /* Initially there is no padding bytes.  */
+  cfun->machine->callee_saved_area_padding_bytes = 0;
+
+  /* Calculate the bytes of saving callee-saved registers on stack.  */
+  cfun->machine->callee_saved_regs_size = 0;
+  cfun->machine->callee_saved_regs_first_regno = SP_REGNUM;
+  cfun->machine->callee_saved_regs_last_regno  = SP_REGNUM;
+  /* Currently, there is no need to check $r28~$r31
+     because we will save them in another way.  */
+  for (r = 0; r < 28; r++)
+    {
+      if (NDS32_REQUIRED_CALLEE_SAVED_P (r))
+	{
+	  /* Mark the first required callee-saved register
+	     (only need to set it once).
+	     If first regno == SP_REGNUM, we can tell that
+	     it is the first time to be here.  */
+	  if (cfun->machine->callee_saved_regs_first_regno == SP_REGNUM)
+	    cfun->machine->callee_saved_regs_first_regno = r;
+	  /* Mark the last required callee-saved register.  */
+	  cfun->machine->callee_saved_regs_last_regno = r;
+	}
+    }
+
+  /* Check if this function can omit prologue/epilogue code fragment.
+     If there is 'naked' attribute in this function,
+     we can set 'naked_p' flag to indicate that
+     we do not have to generate prologue/epilogue.
+     Or, if all the following conditions succeed,
+     we can set this function 'naked_p' as well:
+       condition 1: first_regno == last_regno == SP_REGNUM,
+                    which means we do not have to save
+                    any callee-saved registers.
+       condition 2: Both $lp and $fp are NOT live in this function,
+                    which means we do not need to save them.
+       condition 3: There is no local_size, which means
+                    we do not need to adjust $sp.  */
+  if (lookup_attribute ("naked", DECL_ATTRIBUTES (current_function_decl))
+      || (cfun->machine->callee_saved_regs_first_regno == SP_REGNUM
+	  && cfun->machine->callee_saved_regs_last_regno == SP_REGNUM
+	  && !df_regs_ever_live_p (FP_REGNUM)
+	  && !df_regs_ever_live_p (LP_REGNUM)
+	  && cfun->machine->local_size == 0))
+    {
+      /* Set this function 'naked_p' and
+         other functions can check this flag.  */
+      cfun->machine->naked_p = 1;
+
+      /* No need to save $fp, $gp, and $lp.
+         We should set these value to be zero
+         so that nds32_initial_elimination_offset() can work properly.  */
+      cfun->machine->fp_size = 0;
+      cfun->machine->gp_size = 0;
+      cfun->machine->lp_size = 0;
+
+      /* If stack usage computation is required,
+         we need to provide the static stack size.  */
+      if (flag_stack_usage_info)
+	current_function_static_stack_size = 0;
+
+      /* No need to do following adjustment, return immediately.  */
+      return;
+    }
+
+  /* Adjustment for v3push instructions:
+     If we are using v3push (push25/pop25) instructions,
+     we need to make sure Rb is $r6 and Re is
+     located on $r6, $r8, $r10, or $r14.
+     Some results above will be discarded and recomputed.
+     Note that it is only available under V3/V3M ISA.  */
+  if (TARGET_V3PUSH)
+    {
+      /* Recompute:
+           cfun->machine->fp_size
+           cfun->machine->gp_size
+           cfun->machine->lp_size
+           cfun->machine->callee_saved_regs_first_regno
+           cfun->machine->callee_saved_regs_last_regno */
+
+      /* For v3push instructions, $fp, $gp, and $lp are always saved.  */
+      cfun->machine->fp_size = 4;
+      cfun->machine->gp_size = 4;
+      cfun->machine->lp_size = 4;
+
+      /* Remember to set Rb = $r6.  */
+      cfun->machine->callee_saved_regs_first_regno = 6;
+
+      if (cfun->machine->callee_saved_regs_last_regno <= 6)
+	{
+	  /* Re = $r6 */
+	  cfun->machine->callee_saved_regs_last_regno = 6;
+	}
+      else if (cfun->machine->callee_saved_regs_last_regno <= 8)
+	{
+	  /* Re = $r8 */
+	  cfun->machine->callee_saved_regs_last_regno = 8;
+	}
+      else if (cfun->machine->callee_saved_regs_last_regno <= 10)
+	{
+	  /* Re = $r10 */
+	  cfun->machine->callee_saved_regs_last_regno = 10;
+	}
+      else if (cfun->machine->callee_saved_regs_last_regno <= 14)
+	{
+	  /* Re = $r14 */
+	  cfun->machine->callee_saved_regs_last_regno = 14;
+	}
+      else if (cfun->machine->callee_saved_regs_last_regno == SP_REGNUM)
+	{
+	  /* If last_regno is SP_REGNUM, which means
+	     it is never changed, so set it to Re = $r6.  */
+	  cfun->machine->callee_saved_regs_last_regno = 6;
+	}
+      else
+	{
+	  /* The program flow should not go here.  */
+	  gcc_unreachable ();
+	}
+    }
+
+  /* We have correctly set callee_saved_regs_first_regno
+     and callee_saved_regs_last_regno.
+     Initially, the callee_saved_regs_size is supposed to be 0.
+     As long as callee_saved_regs_last_regno is not SP_REGNUM,
+     we can update callee_saved_regs_size with new size.  */
+  if (cfun->machine->callee_saved_regs_last_regno != SP_REGNUM)
+    {
+      /* Compute pushed size of callee-saved registers.  */
+      cfun->machine->callee_saved_regs_size
+	= 4 * (cfun->machine->callee_saved_regs_last_regno
+	       - cfun->machine->callee_saved_regs_first_regno
+	       + 1);
+    }
+
+  /* Important: We need to make sure that
+                (va_args_size + fp_size + gp_size
+                 + lp_size + callee_saved_regs_size)
+                is 8-byte alignment.
+                If it is not, calculate the padding bytes.  */
+  block_size = cfun->machine->va_args_size
+	       + cfun->machine->fp_size
+	       + cfun->machine->gp_size
+	       + cfun->machine->lp_size
+	       + cfun->machine->callee_saved_regs_size;
+  if (!NDS32_DOUBLE_WORD_ALIGN_P (block_size))
+    {
+      cfun->machine->callee_saved_area_padding_bytes
+	= NDS32_ROUND_UP_DOUBLE_WORD (block_size) - block_size;
+    }
+
+  /* If stack usage computation is required,
+     we need to provide the static stack size.  */
+  if (flag_stack_usage_info)
+    {
+      current_function_static_stack_size
+	= NDS32_ROUND_UP_DOUBLE_WORD (block_size)
+	  + cfun->machine->local_size
+	  + cfun->machine->out_args_size;
+    }
+}
+
+/* Function to create a parallel rtx pattern
+   which presents stack push multiple behavior.
+   The overall concept are:
+     "unspec_stack_push_multiple",
+     "push registers to memory",
+     "adjust stack pointer".  */
+static rtx
+nds32_gen_stack_push_multiple (rtx Rb, rtx Re, rtx En4)
+{
+  int regno;
+  int extra_count;
+  int num_use_regs;
+  int par_index;
+  int offset;
+
+  rtx reg;
+  rtx mem;
+  rtx push_rtx;
+  rtx adjust_sp_rtx;
+  rtx parallel_insn;
+
+  /* We need to provide a customized rtx which contains
+     necessary information for data analysis,
+     so we create a parallel rtx like this:
+     (parallel [(unspec [(reg: Rb)
+                         (reg: Re)
+                         (const_int En4)] UNSPEC_STACK_PUSH_MULTIPLE)
+                (use (reg:SI Rb))
+                (use (reg:SI Re))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -4)))
+                     (reg:SI LP_REGNUM))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -8)))
+                     (reg:SI GP_REGNUM))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -12)))
+                     (reg:SI FP_REGNUM))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -16)))
+                     (reg:SI Re))
+                ...
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -28)))
+                     (reg:SI Rb+1))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -32)))
+                     (reg:SI Rb))
+                (set (reg:SI SP_REGNUM)
+                     (plus (reg:SI SP_REGNUM) (const_int -32)))]) */
+
+  /* Calculate the number of registers that will be pushed.  */
+  extra_count = 0;
+  if (cfun->machine->fp_size)
+    extra_count++;
+  if (cfun->machine->gp_size)
+    extra_count++;
+  if (cfun->machine->lp_size)
+    extra_count++;
+  /* Note that Rb and Re may be SP_REGNUM.  DO NOT count it in.  */
+  if (REGNO (Rb) == SP_REGNUM && REGNO (Re) == SP_REGNUM)
+    num_use_regs = extra_count;
+  else
+    num_use_regs = REGNO (Re) - REGNO (Rb) + 1 + extra_count;
+
+  /* In addition to used registers, we need more spaces for
+     'unspec', 'use Rb', 'use Re', and 'set sp' rtx.  */
+  parallel_insn = gen_rtx_PARALLEL (VOIDmode,
+				    rtvec_alloc (num_use_regs + 1 + 2 + 1));
+  par_index = 0;
+
+  /* Create (unspec [Rb Re En4]).  */
+  XVECEXP (parallel_insn, 0, par_index)
+    = gen_rtx_UNSPEC (BLKmode, gen_rtvec (3, Rb, Re, En4),
+		      UNSPEC_STACK_PUSH_MULTIPLE);
+  par_index++;
+
+  /* Create (use (reg Rb)) and (use (reg Re)).  */
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_USE (VOIDmode, Rb);
+  par_index++;
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_USE (VOIDmode, Re);
+  par_index++;
+
+  /* Initialize offset and start to create push behavior.  */
+  offset = 0;
+
+  /* Create (set mem lp), (set mem gp), and (set mem fp) if necessary.  */
+  if (cfun->machine->lp_size)
+    {
+      offset = offset - 4;
+      reg = gen_rtx_REG (SImode, LP_REGNUM);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      push_rtx = gen_rtx_SET (VOIDmode, mem, reg);
+      XVECEXP (parallel_insn, 0, par_index) = push_rtx;
+      RTX_FRAME_RELATED_P (push_rtx) = 1;
+      par_index++;
+    }
+  if (cfun->machine->gp_size)
+    {
+      offset = offset - 4;
+      reg = gen_rtx_REG (SImode, GP_REGNUM);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      push_rtx = gen_rtx_SET (VOIDmode, mem, reg);
+      XVECEXP (parallel_insn, 0, par_index) = push_rtx;
+      RTX_FRAME_RELATED_P (push_rtx) = 1;
+      par_index++;
+    }
+  if (cfun->machine->fp_size)
+    {
+      offset = offset - 4;
+      reg = gen_rtx_REG (SImode, FP_REGNUM);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      push_rtx = gen_rtx_SET (VOIDmode, mem, reg);
+      XVECEXP (parallel_insn, 0, par_index) = push_rtx;
+      RTX_FRAME_RELATED_P (push_rtx) = 1;
+      par_index++;
+    }
+
+  /* Create (set mem regX) from Re down to Rb+1, Rb.  */
+  for (regno = REGNO (Re); regno >= (int) REGNO (Rb); regno--)
+    {
+      /* Rb and Re may be SP_REGNUM.
+         We need to break this loop immediately.  */
+      if (regno == SP_REGNUM)
+        break;
+
+      offset = offset - 4;
+      reg = gen_rtx_REG (SImode, regno);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      push_rtx = gen_rtx_SET (VOIDmode, mem, reg);
+      XVECEXP (parallel_insn, 0, par_index) = push_rtx;
+      RTX_FRAME_RELATED_P (push_rtx) = 1;
+      par_index++;
+    }
+
+  /* Create (set sp sp-X).  */
+  adjust_sp_rtx
+    = gen_rtx_SET (VOIDmode,
+		   stack_pointer_rtx,
+		   plus_constant (Pmode, stack_pointer_rtx, offset));
+  XVECEXP (parallel_insn, 0, par_index) = adjust_sp_rtx;
+  RTX_FRAME_RELATED_P (adjust_sp_rtx) = 1;
+
+  return parallel_insn;
+}
+
+/* Function to create a parallel rtx pattern
+   which presents stack pop multiple behavior.
+   The overall concept are:
+     "unspec_stack_pop_multiple",
+     "pop registers from memory",
+     "adjust stack pointer".  */
+static rtx
+nds32_gen_stack_pop_multiple (rtx Rb, rtx Re, rtx En4)
+{
+  int regno;
+  int extra_count;
+  int num_use_regs;
+  int par_index;
+  int offset;
+
+  rtx reg;
+  rtx mem;
+  rtx pop_rtx;
+  rtx adjust_sp_rtx;
+  rtx parallel_insn;
+
+  /* We need to provide a customized rtx which contains
+     necessary information for data analysis,
+     so we create a parallel rtx like this:
+     (NOTE: We have to clearly claim that we are using/clobbering Rb and Re,
+            otherwise it may be renamed by optimization.)
+     (parallel [(unspec [(reg: Rb)
+                         (reg: Re)
+                         (const_int En4)] UNSPEC_STACK_POP_MULTIPLE)
+                (use (reg:SI Rb))
+                (use (reg:SI Re))
+                (clobber (reg:SI Rb))
+                (clobber (reg:SI Re))
+                (set (reg:SI Rb)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 0))))
+                (set (reg:SI Rb+1)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 4))))
+                ...
+                (set (reg:SI Re)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 16))))
+                (set (reg:SI FP_REGNUM)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 20))))
+                (set (reg:SI GP_REGNUM)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 24))))
+                (set (reg:SI LP_REGNUM)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 28))))
+                (set (reg:SI SP_REGNUM)
+                     (plus (reg:SI SP_REGNUM) (const_int 32)))]) */
+
+  /* Calculate the number of registers that will be poped.  */
+  extra_count = 0;
+  if (cfun->machine->fp_size)
+    extra_count++;
+  if (cfun->machine->gp_size)
+    extra_count++;
+  if (cfun->machine->lp_size)
+    extra_count++;
+  /* Note that Rb and Re may be SP_REGNUM.  DO NOT count it in.  */
+  if (REGNO (Rb) == SP_REGNUM && REGNO (Re) == SP_REGNUM)
+    num_use_regs = extra_count;
+  else
+    num_use_regs = REGNO (Re) - REGNO (Rb) + 1 + extra_count;
+
+  /* In addition to used registers, we need more spaces for
+     'unspec', 'use Rb', 'use Re', 'clobber Rb', 'clobber Re',
+     and 'set sp' rtx.  */
+  parallel_insn = gen_rtx_PARALLEL (VOIDmode,
+				    rtvec_alloc (num_use_regs + 1 + 4 + 1));
+  par_index = 0;
+
+  /* Create (unspec [Rb Re En4]).  */
+  XVECEXP (parallel_insn, 0, par_index)
+    = gen_rtx_UNSPEC (BLKmode, gen_rtvec (3, Rb, Re, En4),
+		      UNSPEC_STACK_POP_MULTIPLE);
+  par_index++;
+
+  /* Create (use (reg Rb)) and (use (reg Re)).  */
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_USE (VOIDmode, Rb);
+  par_index++;
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_USE (VOIDmode, Re);
+  par_index++;
+  /* Create (clobber (reg Rb)) and (clobber (reg Re)).  */
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_CLOBBER (VOIDmode, Rb);
+  par_index++;
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_CLOBBER (VOIDmode, Re);
+  par_index++;
+
+  /* Initialize offset and start to create pop behavior.  */
+  offset = 0;
+
+  /* Create (set regX mem) from Rb, Rb+1 up to Re.  */
+  for (regno = REGNO (Rb); regno <= (int) REGNO (Re); regno++)
+    {
+      /* Rb and Re may be SP_REGNUM.
+         We need to break this loop immediately.  */
+      if (regno == SP_REGNUM)
+        break;
+
+      reg = gen_rtx_REG (SImode, regno);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      pop_rtx = gen_rtx_SET (VOIDmode, reg, mem);
+      XVECEXP (parallel_insn, 0, par_index) = pop_rtx;
+      RTX_FRAME_RELATED_P (pop_rtx) = 1;
+      offset = offset + 4;
+      par_index++;
+    }
+
+  /* Create (set fp mem), (set gp mem), and (set lp mem) if necessary.  */
+  if (cfun->machine->fp_size)
+    {
+      reg = gen_rtx_REG (SImode, FP_REGNUM);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      pop_rtx = gen_rtx_SET (VOIDmode, reg, mem);
+      XVECEXP (parallel_insn, 0, par_index) = pop_rtx;
+      RTX_FRAME_RELATED_P (pop_rtx) = 1;
+      offset = offset + 4;
+      par_index++;
+    }
+  if (cfun->machine->gp_size)
+    {
+      reg = gen_rtx_REG (SImode, GP_REGNUM);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      pop_rtx = gen_rtx_SET (VOIDmode, reg, mem);
+      XVECEXP (parallel_insn, 0, par_index) = pop_rtx;
+      RTX_FRAME_RELATED_P (pop_rtx) = 1;
+      offset = offset + 4;
+      par_index++;
+    }
+  if (cfun->machine->lp_size)
+    {
+      reg = gen_rtx_REG (SImode, LP_REGNUM);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      pop_rtx = gen_rtx_SET (VOIDmode, reg, mem);
+      XVECEXP (parallel_insn, 0, par_index) = pop_rtx;
+      RTX_FRAME_RELATED_P (pop_rtx) = 1;
+      offset = offset + 4;
+      par_index++;
+    }
+
+  /* Create (set sp sp+X).  */
+  adjust_sp_rtx
+    = gen_rtx_SET (VOIDmode,
+		   stack_pointer_rtx,
+		   plus_constant (Pmode, stack_pointer_rtx, offset));
+  XVECEXP (parallel_insn, 0, par_index) = adjust_sp_rtx;
+  RTX_FRAME_RELATED_P (adjust_sp_rtx) = 1;
+
+  return parallel_insn;
+}
+
+/* Function to create a parallel rtx pattern
+   which presents stack v3push behavior.
+   The overall concept are:
+     "unspec_stack_v3push",
+     "push registers to memory",
+     "adjust stack pointer".  */
+static rtx
+nds32_gen_stack_v3push (rtx Rb,
+			rtx Re,
+			rtx En4 ATTRIBUTE_UNUSED,
+			rtx imm8u)
+{
+  int regno;
+  int num_use_regs;
+  int par_index;
+  int offset;
+
+  rtx reg;
+  rtx mem;
+  rtx push_rtx;
+  rtx adjust_sp_rtx;
+  rtx parallel_insn;
+
+  /* We need to provide a customized rtx which contains
+     necessary information for data analysis,
+     so we create a parallel rtx like this:
+     (parallel [(unspec [(reg: Re)
+                         (const_int imm8u)] UNSPEC_STACK_V3PUSH)
+                (use (reg:SI Re))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -4)))
+                     (reg:SI LP_REGNUM))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -8)))
+                     (reg:SI GP_REGNUM))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -12)))
+                     (reg:SI FP_REGNUM))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -16)))
+                     (reg:SI Re))
+                ...
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -28)))
+                     (reg:SI Rb+1))
+                (set (mem (plus (reg:SI SP_REGNUM) (const_int -32)))
+                     (reg:SI Rb))
+                (set (reg:SI SP_REGNUM)
+                     (plus (reg:SI SP_REGNUM) (const_int -32-imm8u)))]) */
+
+  /* Calculate the number of registers that will be pushed.
+     Since $fp, $gp, and $lp is always pushed with v3push instruction,
+     we need to count these three regs.
+     Under v3push, Rb is $r6, while Re is $r6, $r8, $r10, or $r14.
+     So there is no need to worry about Rb=Re=SP_REGNUM case.  */
+  num_use_regs = REGNO (Re) - REGNO (Rb) + 1 + 3;
+
+  /* In addition to used registers, we need more spaces for
+     'unspec', 'use Re', and 'set sp sp-x-imm8u' rtx.  */
+  parallel_insn = gen_rtx_PARALLEL (VOIDmode,
+				    rtvec_alloc (num_use_regs + 1 + 1 + 1));
+  par_index = 0;
+
+  /* Create (unspec [Re imm8u]).  */
+  XVECEXP (parallel_insn, 0, par_index)
+    = gen_rtx_UNSPEC (BLKmode, gen_rtvec (2, Re, imm8u),
+		      UNSPEC_STACK_V3PUSH);
+  par_index++;
+
+  /* Create (use (reg Re)).  */
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_USE (VOIDmode, Re);
+  par_index++;
+
+  /* Initialize offset and start to create push behavior.  */
+  offset = 0;
+
+  /* Create (set mem lp).  */
+  offset = offset - 4;
+  reg = gen_rtx_REG (SImode, LP_REGNUM);
+  mem = gen_frame_mem (SImode, plus_constant (Pmode,
+					      stack_pointer_rtx,
+					      offset));
+  push_rtx = gen_rtx_SET (VOIDmode, mem, reg);
+  XVECEXP (parallel_insn, 0, par_index) = push_rtx;
+  RTX_FRAME_RELATED_P (push_rtx) = 1;
+  par_index++;
+  /* Create (set mem gp).  */
+  offset = offset - 4;
+  reg = gen_rtx_REG (SImode, GP_REGNUM);
+  mem = gen_frame_mem (SImode, plus_constant (Pmode,
+					      stack_pointer_rtx,
+					      offset));
+  push_rtx = gen_rtx_SET (VOIDmode, mem, reg);
+  XVECEXP (parallel_insn, 0, par_index) = push_rtx;
+  RTX_FRAME_RELATED_P (push_rtx) = 1;
+  par_index++;
+  /* Create (set mem fp).  */
+  offset = offset - 4;
+  reg = gen_rtx_REG (SImode, FP_REGNUM);
+  mem = gen_frame_mem (SImode, plus_constant (Pmode,
+					      stack_pointer_rtx,
+					      offset));
+  push_rtx = gen_rtx_SET (VOIDmode, mem, reg);
+  XVECEXP (parallel_insn, 0, par_index) = push_rtx;
+  RTX_FRAME_RELATED_P (push_rtx) = 1;
+  par_index++;
+
+  /* Create (set mem regX) from Re down to Rb+1, Rb.
+     Under v3push, Rb is $r6, while Re is $r6, $r8, $r10, or $r14.
+     So there is no need to worry about Rb=Re=SP_REGNUM case.  */
+  for (regno = REGNO (Re); regno >= (int) REGNO (Rb); regno--)
+    {
+      offset = offset - 4;
+      reg = gen_rtx_REG (SImode, regno);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      push_rtx = gen_rtx_SET (VOIDmode, mem, reg);
+      XVECEXP (parallel_insn, 0, par_index) = push_rtx;
+      RTX_FRAME_RELATED_P (push_rtx) = 1;
+      par_index++;
+    }
+
+  /* Create (set sp sp-x-imm8u).  */
+  adjust_sp_rtx
+    = gen_rtx_SET (VOIDmode,
+		   stack_pointer_rtx,
+		   plus_constant (Pmode,
+				  stack_pointer_rtx,
+				  offset - INTVAL (imm8u)));
+  XVECEXP (parallel_insn, 0, par_index) = adjust_sp_rtx;
+  RTX_FRAME_RELATED_P (adjust_sp_rtx) = 1;
+
+  return parallel_insn;
+}
+
+/* Function to create a parallel rtx pattern
+   which presents stack v3pop behavior.
+   The overall concept are:
+     "unspec_stack_v3pop",
+     "pop registers from memory",
+     "adjust stack pointer".  */
+static rtx
+nds32_gen_stack_v3pop (rtx Rb,
+		       rtx Re,
+		       rtx En4 ATTRIBUTE_UNUSED,
+		       rtx imm8u)
+{
+  int regno;
+  int num_use_regs;
+  int par_index;
+  int offset;
+
+  rtx reg;
+  rtx mem;
+  rtx pop_rtx;
+  rtx adjust_sp_rtx;
+  rtx parallel_insn;
+
+  /* We need to provide a customized rtx which contains
+     necessary information for data analysis,
+     so we create a parallel rtx like this:
+     (NOTE: We have to clearly claim that we are using/clobbering Re,
+            otherwise it may be renamed by optimization.)
+     (parallel [(unspec [(reg: Re)
+                         (const_int imm8u)] UNSPEC_STACK_V3POP)
+                (use (reg:SI Re))
+                (clobber (reg:SI Re))
+                (set (reg:SI Rb)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 0))))
+                (set (reg:SI Rb+1)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 4))))
+                ...
+                (set (reg:SI Re)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 16))))
+                (set (reg:SI FP_REGNUM)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 20))))
+                (set (reg:SI GP_REGNUM)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 24))))
+                (set (reg:SI LP_REGNUM)
+                     (mem (plus (reg:SI SP_REGNUM) (const_int 28))))
+                (set (reg:SI SP_REGNUM)
+                     (plus (reg:SI SP_REGNUM) (const_int 32+imm8u)))]) */
+
+  /* Calculate the number of registers that will be poped.
+     Since $fp, $gp, and $lp is always poped with v3pop instruction,
+     we need to count these three regs.
+     Under v3push, Rb is $r6, while Re is $r6, $r8, $r10, or $r14.
+     So there is no need to worry about Rb=Re=SP_REGNUM case.  */
+  num_use_regs = REGNO (Re) - REGNO (Rb) + 1 + 3;
+
+  /* In addition to used registers, we need more spaces for
+     'unspec', 'use Re', 'clobber Re',
+     and 'set sp sp+x+imm8u' rtx.  */
+  parallel_insn = gen_rtx_PARALLEL (VOIDmode,
+				    rtvec_alloc (num_use_regs + 1 + 2 + 1));
+  par_index = 0;
+
+  /* Create (unspec [Re imm8u]).  */
+  XVECEXP (parallel_insn, 0, par_index)
+    = gen_rtx_UNSPEC (BLKmode, gen_rtvec (2, Re, imm8u),
+		      UNSPEC_STACK_V3POP);
+  par_index++;
+
+  /* Create (use (reg Re)).  */
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_USE (VOIDmode, Re);
+  par_index++;
+  /* Create (clobber (reg Re)).  */
+  XVECEXP (parallel_insn, 0, par_index) = gen_rtx_CLOBBER (VOIDmode, Re);
+  par_index++;
+
+  /* Initialize offset and start to create pop behavior.  */
+  offset = 0;
+
+  /* Create (set regX mem) from Rb, Rb+1 up to Re.
+     Under v3pop, Rb is $r6, while Re is $r6, $r8, $r10, or $r14.
+     So there is no need to worry about Rb=Re=SP_REGNUM case.  */
+  for (regno = REGNO (Rb); regno <= (int) REGNO (Re); regno++)
+    {
+      reg = gen_rtx_REG (SImode, regno);
+      mem = gen_frame_mem (SImode, plus_constant (Pmode,
+						  stack_pointer_rtx,
+						  offset));
+      pop_rtx = gen_rtx_SET (VOIDmode, reg, mem);
+      XVECEXP (parallel_insn, 0, par_index) = pop_rtx;
+      RTX_FRAME_RELATED_P (pop_rtx) = 1;
+      offset = offset + 4;
+      par_index++;
+    }
+
+  /* Create (set mem fp).  */
+  reg = gen_rtx_REG (SImode, FP_REGNUM);
+  mem = gen_frame_mem (SImode, plus_constant (Pmode,
+					      stack_pointer_rtx,
+					      offset));
+  pop_rtx = gen_rtx_SET (VOIDmode, reg, mem);
+  XVECEXP (parallel_insn, 0, par_index) = pop_rtx;
+  RTX_FRAME_RELATED_P (pop_rtx) = 1;
+  offset = offset + 4;
+  par_index++;
+  /* Create (set mem gp).  */
+  reg = gen_rtx_REG (SImode, GP_REGNUM);
+  mem = gen_frame_mem (SImode, plus_constant (Pmode,
+					      stack_pointer_rtx,
+					      offset));
+  pop_rtx = gen_rtx_SET (VOIDmode, reg, mem);
+  XVECEXP (parallel_insn, 0, par_index) = pop_rtx;
+  RTX_FRAME_RELATED_P (pop_rtx) = 1;
+  offset = offset + 4;
+  par_index++;
+  /* Create (set mem lp).  */
+  reg = gen_rtx_REG (SImode, LP_REGNUM);
+  mem = gen_frame_mem (SImode, plus_constant (Pmode,
+					      stack_pointer_rtx,
+					      offset));
+  pop_rtx = gen_rtx_SET (VOIDmode, reg, mem);
+  XVECEXP (parallel_insn, 0, par_index) = pop_rtx;
+  RTX_FRAME_RELATED_P (pop_rtx) = 1;
+  offset = offset + 4;
+  par_index++;
+
+  /* Create (set sp sp+x+imm8u).  */
+  adjust_sp_rtx
+    = gen_rtx_SET (VOIDmode,
+		   stack_pointer_rtx,
+		   plus_constant (Pmode,
+				  stack_pointer_rtx,
+				  offset + INTVAL (imm8u)));
+  XVECEXP (parallel_insn, 0, par_index) = adjust_sp_rtx;
+  RTX_FRAME_RELATED_P (adjust_sp_rtx) = 1;
+
+  return parallel_insn;
+}
+
+/* A helper function to emit section head template.  */
+static void
+nds32_emit_section_head_template (char section_name[],
+				  char symbol_name[],
+				  int align_value,
+				  bool object_p)
+{
+  const char *flags_str;
+  const char *type_str;
+
+  flags_str = (object_p) ? "\"a\"" : "\"ax\"";
+  type_str = (object_p) ? "@object" : "@function";
+
+  fprintf (asm_out_file, "\t.section\t%s, %s\n", section_name, flags_str);
+  fprintf (asm_out_file, "\t.align\t%d\n", align_value);
+  fprintf (asm_out_file, "\t.global\t%s\n", symbol_name);
+  fprintf (asm_out_file, "\t.type\t%s, %s\n", symbol_name, type_str);
+  fprintf (asm_out_file, "%s:\n", symbol_name);
+}
+
+/* A helper function to emit section tail template.  */
+static void
+nds32_emit_section_tail_template (char symbol_name[])
+{
+  fprintf (asm_out_file, "\t.size\t%s, .-%s\n", symbol_name, symbol_name);
+}
+
+/* Function to emit isr jump table section.  */
+static void
+nds32_emit_isr_jmptbl_section (int vector_id)
+{
+  char section_name[100];
+  char symbol_name[100];
+
+  /* Prepare jmptbl section and symbol name.  */
+  snprintf (section_name, sizeof (section_name),
+	    ".nds32_jmptbl.%02d", vector_id);
+  snprintf (symbol_name, sizeof (symbol_name),
+	    "_nds32_jmptbl_%02d", vector_id);
+
+  nds32_emit_section_head_template (section_name, symbol_name, 2, true);
+  fprintf (asm_out_file, "\t.word\t%s\n",
+			 nds32_isr_vectors[vector_id].func_name);
+  nds32_emit_section_tail_template (symbol_name);
+}
+
+/* Function to emit isr vector section.  */
+static void
+nds32_emit_isr_vector_section (int vector_id)
+{
+  unsigned int vector_number_offset = 0;
+  const char *c_str = "CATEGORY";
+  const char *sr_str = "SR";
+  const char *nt_str = "NT";
+  const char *vs_str = "VS";
+  char first_level_handler_name[100];
+  char section_name[100];
+  char symbol_name[100];
+
+  /* Set the vector number offset so that we can calculate
+     the value that user specifies in the attribute.
+     We also prepare the category string for first level handler name.  */
+  switch (nds32_isr_vectors[vector_id].category)
+    {
+    case NDS32_ISR_INTERRUPT:
+      vector_number_offset = 9;
+      c_str = "i";
+      break;
+    case NDS32_ISR_EXCEPTION:
+      vector_number_offset = 0;
+      c_str = "e";
+      break;
+    case NDS32_ISR_NONE:
+    case NDS32_ISR_RESET:
+      /* Normally it should not be here.  */
+      gcc_unreachable ();
+      break;
+    }
+
+  /* Prepare save reg string for first level handler name.  */
+  switch (nds32_isr_vectors[vector_id].save_reg)
+    {
+    case NDS32_SAVE_ALL:
+      sr_str = "sa";
+      break;
+    case NDS32_PARTIAL_SAVE:
+      sr_str = "ps";
+      break;
+    }
+
+  /* Prepare nested type string for first level handler name.  */
+  switch (nds32_isr_vectors[vector_id].nested_type)
+    {
+    case NDS32_NESTED:
+      nt_str = "ns";
+      break;
+    case NDS32_NOT_NESTED:
+      nt_str = "nn";
+      break;
+    case NDS32_NESTED_READY:
+      nt_str = "nr";
+      break;
+    }
+
+  /* Currently we have 4-byte or 16-byte size for each vector.
+     If it is 4-byte, the first level handler name has suffix string "_4b".  */
+  vs_str = (nds32_isr_vector_size == 4) ? "_4b" : "";
+
+  /* Now we can create first level handler name.  */
+  snprintf (first_level_handler_name, sizeof (first_level_handler_name),
+	    "_nds32_%s_%s_%s%s", c_str, sr_str, nt_str, vs_str);
+
+  /* Prepare vector section and symbol name.  */
+  snprintf (section_name, sizeof (section_name),
+	    ".nds32_vector.%02d", vector_id);
+  snprintf (symbol_name, sizeof (symbol_name),
+	    "_nds32_vector_%02d%s", vector_id, vs_str);
+
+
+  /* Everything is ready.  We can start emit vector section content.  */
+  nds32_emit_section_head_template (section_name, symbol_name,
+				    floor_log2 (nds32_isr_vector_size), false);
+
+  /* According to the vector size, the instructions in the
+     vector section may be different.  */
+  if (nds32_isr_vector_size == 4)
+    {
+      /* This block is for 4-byte vector size.
+         Hardware $VID support is necessary and only one instruction
+         is needed in vector section.  */
+      fprintf (asm_out_file, "\tj\t%s ! jump to first level handler\n",
+			     first_level_handler_name);
+    }
+  else
+    {
+      /* This block is for 16-byte vector size.
+         There is NO hardware $VID so that we need several instructions
+         such as pushing GPRs and preparing software vid at vector section.
+         For pushing GPRs, there are four variations for
+         16-byte vector content and we have to handle each combination.
+         For preparing software vid, note that the vid need to
+         be substracted vector_number_offset.  */
+      if (TARGET_REDUCED_REGS)
+	{
+	  if (nds32_isr_vectors[vector_id].save_reg == NDS32_SAVE_ALL)
+	    {
+	      /* Case of reduced set registers and save_all attribute.  */
+	      fprintf (asm_out_file, "\t! reduced set regs + save_all\n");
+	      fprintf (asm_out_file, "\tsmw.adm\t$r15, [$sp], $r15, 0xf\n");
+	      fprintf (asm_out_file, "\tsmw.adm\t$r0, [$sp], $r10, 0x0\n");
+
+	    }
+	  else
+	    {
+	      /* Case of reduced set registers and partial_save attribute.  */
+	      fprintf (asm_out_file, "\t! reduced set regs + partial_save\n");
+	      fprintf (asm_out_file, "\tsmw.adm\t$r15, [$sp], $r15, 0x2\n");
+	      fprintf (asm_out_file, "\tsmw.adm\t$r0, [$sp], $r5, 0x0\n");
+	    }
+	}
+      else
+	{
+	  if (nds32_isr_vectors[vector_id].save_reg == NDS32_SAVE_ALL)
+	    {
+	      /* Case of full set registers and save_all attribute.  */
+	      fprintf (asm_out_file, "\t! full set regs + save_all\n");
+	      fprintf (asm_out_file, "\tsmw.adm\t$r0, [$sp], $r27, 0xf\n");
+	    }
+	  else
+	    {
+	      /* Case of full set registers and partial_save attribute.  */
+	      fprintf (asm_out_file, "\t! full set regs + partial_save\n");
+	      fprintf (asm_out_file, "\tsmw.adm\t$r15, [$sp], $r27, 0x2\n");
+	      fprintf (asm_out_file, "\tsmw.adm\t$r0, [$sp], $r5, 0x0\n");
+	    }
+	}
+
+      fprintf (asm_out_file, "\tmovi\t$r0, %d ! preparing software vid\n",
+			     vector_id - vector_number_offset);
+      fprintf (asm_out_file, "\tj\t%s ! jump to first level handler\n",
+			     first_level_handler_name);
+    }
+
+  nds32_emit_section_tail_template (symbol_name);
+}
+
+/* Function to emit isr reset handler content.
+   Including all jmptbl/vector references, jmptbl section,
+   vector section, nmi handler section, and warm handler section.  */
+static void
+nds32_emit_isr_reset_content (void)
+{
+  unsigned int i;
+  unsigned int total_n_vectors;
+  const char *vs_str;
+  char reset_handler_name[100];
+  char section_name[100];
+  char symbol_name[100];
+
+  total_n_vectors = nds32_isr_vectors[0].total_n_vectors;
+  vs_str = (nds32_isr_vector_size == 4) ? "_4b" : "";
+
+  fprintf (asm_out_file, "\t! RESET HANDLER CONTENT - BEGIN !\n");
+
+  /* Create references in .rodata according to total number of vectors.  */
+  fprintf (asm_out_file, "\t.section\t.rodata\n");
+  fprintf (asm_out_file, "\t.align\t2\n");
+
+  /* Emit jmptbl references.  */
+  fprintf (asm_out_file, "\t ! references to jmptbl section entries\n");
+  for (i = 0; i < total_n_vectors; i++)
+    fprintf (asm_out_file, "\t.word\t_nds32_jmptbl_%02d\n", i);
+
+  /* Emit vector references.  */
+  fprintf (asm_out_file, "\t ! references to vector section entries\n");
+  for (i = 0; i < total_n_vectors; i++)
+    fprintf (asm_out_file, "\t.word\t_nds32_vector_%02d%s\n", i, vs_str);
+
+  /* Emit jmptbl_00 section.  */
+  snprintf (section_name, sizeof (section_name), ".nds32_jmptbl.00");
+  snprintf (symbol_name, sizeof (symbol_name), "_nds32_jmptbl_00");
+
+  fprintf (asm_out_file, "\t! ....................................\n");
+  nds32_emit_section_head_template (section_name, symbol_name, 2, true);
+  fprintf (asm_out_file, "\t.word\t%s\n",
+			 nds32_isr_vectors[0].func_name);
+  nds32_emit_section_tail_template (symbol_name);
+
+  /* Emit vector_00 section.  */
+  snprintf (section_name, sizeof (section_name), ".nds32_vector.00");
+  snprintf (symbol_name, sizeof (symbol_name), "_nds32_vector_00%s", vs_str);
+  snprintf (reset_handler_name, sizeof (reset_handler_name),
+	    "_nds32_reset%s", vs_str);
+
+  fprintf (asm_out_file, "\t! ....................................\n");
+  nds32_emit_section_head_template (section_name, symbol_name,
+				    floor_log2 (nds32_isr_vector_size), false);
+  fprintf (asm_out_file, "\tj\t%s ! jump to reset handler\n",
+			 reset_handler_name);
+  nds32_emit_section_tail_template (symbol_name);
+
+  /* Emit nmi handler section.  */
+  snprintf (section_name, sizeof (section_name), ".nds32_nmih");
+  snprintf (symbol_name, sizeof (symbol_name), "_nds32_nmih");
+
+  fprintf (asm_out_file, "\t! ....................................\n");
+  nds32_emit_section_head_template (section_name, symbol_name, 2, true);
+  fprintf (asm_out_file, "\t.word\t%s\n",
+			 (strlen (nds32_isr_vectors[0].nmi_name) == 0)
+			 ? "0"
+			 : nds32_isr_vectors[0].nmi_name);
+  nds32_emit_section_tail_template (symbol_name);
+
+  /* Emit warm handler section.  */
+  snprintf (section_name, sizeof (section_name), ".nds32_wrh");
+  snprintf (symbol_name, sizeof (symbol_name), "_nds32_wrh");
+
+  fprintf (asm_out_file, "\t! ....................................\n");
+  nds32_emit_section_head_template (section_name, symbol_name, 2, true);
+  fprintf (asm_out_file, "\t.word\t%s\n",
+			 (strlen (nds32_isr_vectors[0].warm_name) == 0)
+			 ? "0"
+			 : nds32_isr_vectors[0].warm_name);
+  nds32_emit_section_tail_template (symbol_name);
+
+  fprintf (asm_out_file, "\t! RESET HANDLER CONTENT - END !\n");
+}
+
+/* Function for nds32_merge_decl_attributes() and nds32_insert_attributes()
+   to check if there are any conflict isr-specific attributes being set.
+   We need to check:
+     1. Only 'save_all' or 'partial_save' in the attributes.
+     2. Only 'nested', 'not_nested', or 'nested_ready' in the attributes.
+     3. Only 'interrupt', 'exception', or 'reset' in the attributes.  */
+static void
+nds32_check_isr_attrs_conflict (const char *func_name, tree func_attrs)
+{
+  int save_all_p, partial_save_p;
+  int nested_p, not_nested_p, nested_ready_p;
+  int intr_p, excp_p, reset_p;
+
+  /* Initialize variables.  */
+  save_all_p = partial_save_p = 0;
+  nested_p = not_nested_p = nested_ready_p = 0;
+  intr_p = excp_p = reset_p = 0;
+
+  /* We must check at MOST one attribute to set save-reg.  */
+  if (lookup_attribute ("save_all", func_attrs))
+    save_all_p = 1;
+  if (lookup_attribute ("partial_save", func_attrs))
+    partial_save_p = 1;
+
+  if ((save_all_p + partial_save_p) > 1)
+    error ("multiple save reg attributes to function %qs", func_name);
+
+  /* We must check at MOST one attribute to set nested-type.  */
+  if (lookup_attribute ("nested", func_attrs))
+    nested_p = 1;
+  if (lookup_attribute ("not_nested", func_attrs))
+    not_nested_p = 1;
+  if (lookup_attribute ("nested_ready", func_attrs))
+    nested_ready_p = 1;
+
+  if ((nested_p + not_nested_p + nested_ready_p) > 1)
+    error ("multiple nested types attributes to function %qs", func_name);
+
+  /* We must check at MOST one attribute to
+     set interrupt/exception/reset.  */
+  if (lookup_attribute ("interrupt", func_attrs))
+    intr_p = 1;
+  if (lookup_attribute ("exception", func_attrs))
+    excp_p = 1;
+  if (lookup_attribute ("reset", func_attrs))
+    reset_p = 1;
+
+  if ((intr_p + excp_p + reset_p) > 1)
+    error ("multiple interrupt attributes to function %qs", func_name);
+}
+
+/* Function to construct isr vectors information array.
+   We DO NOT HAVE TO check if the attributes are valid
+   because those works are supposed to be done on
+   nds32_merge_decl_attributes() and nds32_insert_attributes().  */
+static void
+nds32_construct_isr_vectors_information (tree func_attrs,
+					 const char *func_name)
+{
+  tree save_all, partial_save;
+  tree nested, not_nested, nested_ready;
+  tree intr, excp, reset;
+
+  save_all     = lookup_attribute ("save_all", func_attrs);
+  partial_save = lookup_attribute ("partial_save", func_attrs);
+
+  nested       = lookup_attribute ("nested", func_attrs);
+  not_nested   = lookup_attribute ("not_nested", func_attrs);
+  nested_ready = lookup_attribute ("nested_ready", func_attrs);
+
+  intr  = lookup_attribute ("interrupt", func_attrs);
+  excp  = lookup_attribute ("exception", func_attrs);
+  reset = lookup_attribute ("reset", func_attrs);
+
+  /* If there is no interrupt/exception/reset, we can return immediately.  */
+  if (!intr && !excp && !reset)
+    return;
+
+  /* If we are here, either we have interrupt/exception,
+     or reset attribute.  */
+  if (intr || excp)
+    {
+      tree id_list;
+
+      /* Prepare id list so that we can traverse and set vector id.  */
+      id_list = (intr) ? (TREE_VALUE (intr)) : (TREE_VALUE (excp));
+
+      while (id_list)
+	{
+	  tree id;
+	  int vector_id;
+	  unsigned int vector_number_offset;
+
+	  /* The way to handle interrupt or exception is the same,
+	     we just need to take care of actual vector number.
+	     For interrupt(0..63), the actual vector number is (9..72).
+	     For exception(1..8), the actual vector number is (1..8).  */
+	  vector_number_offset = (intr) ? (9) : (0);
+
+	  /* Pick up each vector id value.  */
+	  id = TREE_VALUE (id_list);
+	  /* Add vector_number_offset to get actual vector number.  */
+	  vector_id = TREE_INT_CST_LOW (id) + vector_number_offset;
+
+	  /* Enable corresponding vector and set function name.  */
+	  nds32_isr_vectors[vector_id].category = (intr)
+						  ? (NDS32_ISR_INTERRUPT)
+						  : (NDS32_ISR_EXCEPTION);
+	  strcpy (nds32_isr_vectors[vector_id].func_name, func_name);
+
+	  /* Set register saving scheme.  */
+	  if (save_all)
+	    nds32_isr_vectors[vector_id].save_reg = NDS32_SAVE_ALL;
+	  else if (partial_save)
+	    nds32_isr_vectors[vector_id].save_reg = NDS32_PARTIAL_SAVE;
+
+	  /* Set nested type.  */
+	  if (nested)
+	    nds32_isr_vectors[vector_id].nested_type = NDS32_NESTED;
+	  else if (not_nested)
+	    nds32_isr_vectors[vector_id].nested_type = NDS32_NOT_NESTED;
+	  else if (nested_ready)
+	    nds32_isr_vectors[vector_id].nested_type = NDS32_NESTED_READY;
+
+	  /* Advance to next id.  */
+	  id_list = TREE_CHAIN (id_list);
+	}
+    }
+  else
+    {
+      tree id_list;
+      tree id;
+      tree nmi, warm;
+
+      /* Deal with reset attribute.  Its vector number is always 0.  */
+      nds32_isr_vectors[0].category = NDS32_ISR_RESET;
+
+      /* Prepare id_list and identify id value so that
+         we can set total number of vectors.  */
+      id_list = TREE_VALUE (reset);
+      id = TREE_VALUE (id_list);
+
+      /* The total vectors = interrupt + exception numbers + reset.
+         There are 8 exception and 1 reset in nds32 architecture.  */
+      nds32_isr_vectors[0].total_n_vectors = TREE_INT_CST_LOW (id) + 8 + 1;
+      strcpy (nds32_isr_vectors[0].func_name, func_name);
+
+      /* Retrieve nmi and warm function.  */
+      nmi  = lookup_attribute ("nmi", func_attrs);
+      warm = lookup_attribute ("warm", func_attrs);
+
+      if (nmi != NULL_TREE)
+	{
+	  tree nmi_func_list;
+	  tree nmi_func;
+
+	  nmi_func_list = TREE_VALUE (nmi);
+	  nmi_func = TREE_VALUE (nmi_func_list);
+
+	  /* Record nmi function name.  */
+	  strcpy (nds32_isr_vectors[0].nmi_name,
+		  IDENTIFIER_POINTER (nmi_func));
+	}
+
+      if (warm != NULL_TREE)
+	{
+	  tree warm_func_list;
+	  tree warm_func;
+
+	  warm_func_list = TREE_VALUE (warm);
+	  warm_func = TREE_VALUE (warm_func_list);
+
+	  /* Record warm function name.  */
+	  strcpy (nds32_isr_vectors[0].warm_name,
+		  IDENTIFIER_POINTER (warm_func));
+	}
+    }
+}
+
+/* Function that may creates more instructions
+   for large value on adjusting stack pointer.
+
+   In nds32 target, 'addi' can be used for stack pointer
+   adjustment in prologue/epilogue stage.
+   However, sometimes there are too many local variables so that
+   the adjustment value is not able to be fit in the 'addi' instruction.
+   One solution is to move value into a register
+   and then use 'add' instruction.
+   In practice, we use TA_REGNUM ($r15) to accomplish this purpose.
+   Also, we need to return zero for sp adjustment so that
+   proglogue/epilogue knows there is no need to create 'addi' instruction.  */
+static int
+nds32_force_addi_stack_int (int full_value)
+{
+  int adjust_value;
+
+  rtx tmp_reg;
+  rtx value_move_insn;
+  rtx sp_adjust_insn;
+
+  if (!satisfies_constraint_Is15 (GEN_INT (full_value)))
+    {
+      /* The value is not able to fit in single addi instruction.
+         Create more instructions of moving value into a register
+         and then add stack pointer with it.  */
+
+      /* $r15 is going to be temporary register to hold the value.  */
+      tmp_reg = gen_rtx_REG (SImode, TA_REGNUM);
+
+      /* Create one more instruction to move value
+         into the temporary register.  */
+      value_move_insn = emit_move_insn (tmp_reg, GEN_INT (full_value));
+
+      /* At prologue, we need to tell GCC that this is frame related insn,
+         so that we can consider this instruction to output debug information.
+         If full_value is NEGATIVE, it means this function
+         is invoked by expand_prologue.  */
+      if (full_value < 0)
+	RTX_FRAME_RELATED_P (value_move_insn) = 1;
+
+      /* Create new 'add' rtx.  */
+      sp_adjust_insn = gen_addsi3 (stack_pointer_rtx,
+				   stack_pointer_rtx,
+				   tmp_reg);
+      /* Emit rtx into insn list and receive its transformed insn rtx.  */
+      sp_adjust_insn = emit_insn (sp_adjust_insn);
+
+      /* At prologue, we need to tell GCC that this is frame related insn,
+         so that we can consider this instruction to output debug information.
+         If full_value is NEGATIVE, it means this function
+         is invoked by expand_prologue.  */
+      if (full_value < 0)
+	RTX_FRAME_RELATED_P (sp_adjust_insn) = 1;
+
+      /* We have used alternative way to adjust stack pointer value.
+         Return zero so that prologue/epilogue
+         will not generate other instructions.  */
+      return 0;
+    }
+  else
+    {
+      /* The value is able to fit in addi instruction.
+         However, remember to make it to be positive value
+         because we want to return 'adjustment' result.  */
+      adjust_value = (full_value < 0) ? (-full_value) : (full_value);
+
+      return adjust_value;
+    }
+}
+
+/* Return true if MODE/TYPE need double word alignment.  */
+static bool
+nds32_needs_double_word_align (enum machine_mode mode, const_tree type)
+{
+  unsigned int align;
+
+  /* When 'type' is nonnull, there is no need to look at 'mode'.  */
+  align = (type ? TYPE_ALIGN (type) : GET_MODE_ALIGNMENT (mode));
+
+  return (align > PARM_BOUNDARY);
+}
+
+/* Return true if FUNC is a naked function.  */
+static bool nds32_naked_function_p (tree func)
+{
+  tree t;
+
+  if (TREE_CODE (func) != FUNCTION_DECL)
+    abort ();
+
+  t = lookup_attribute ("naked", DECL_ATTRIBUTES (func));
+
+  return (t != NULL_TREE);
+}
+
+/* Function that check if 'X' is a valid address register.
+   The variable 'STRICT' is very important to
+   make decision for register number.
+
+   STRICT : true
+     => We are in reload pass or after reload pass.
+        The register number should be strictly limited in general registers.
+
+   STRICT : false
+     => Before reload pass, we are free to use any register number.  */
+static bool
+nds32_address_register_rtx_p (rtx x, bool strict)
+{
+  int regno;
+
+  if (GET_CODE (x) != REG)
+    return false;
+
+  regno = REGNO (x);
+
+  if (strict)
+    return REGNO_OK_FOR_BASE_P (regno);
+  else
+    return true;
+}
+
+/* Function that check if 'INDEX' is valid to be a index rtx for address.
+
+   OUTER_MODE : Machine mode of outer address rtx.
+        INDEX : Check if this rtx is valid to be a index for address.
+       STRICT : If it is true, we are in reload pass or after reload pass.  */
+static bool
+nds32_legitimate_index_p (enum machine_mode outer_mode,
+			  rtx index,
+			  bool strict)
+{
+  int regno;
+  rtx op0;
+  rtx op1;
+
+  switch (GET_CODE (index))
+    {
+    case REG:
+      regno = REGNO (index);
+      /* If we are in reload pass or after reload pass,
+         we need to limit it to general register.  */
+      if (strict)
+	return REGNO_OK_FOR_INDEX_P (regno);
+      else
+	return true;
+
+    case CONST_INT:
+      /* The alignment of the integer value is determined by 'outer_mode'.  */
+      if (GET_MODE_SIZE (outer_mode) == 1)
+	{
+	  /* Further check if the value is legal for the 'outer_mode'.  */
+	  if (!satisfies_constraint_Is15 (index))
+	    return false;
+
+	  /* Pass all test, the value is valid, return true.  */
+	  return true;
+	}
+      if (GET_MODE_SIZE (outer_mode) == 2
+	  && NDS32_HALF_WORD_ALIGN_P (INTVAL (index)))
+	{
+	  /* Further check if the value is legal for the 'outer_mode'.  */
+	  if (!satisfies_constraint_Is16 (index))
+	    return false;
+
+	  /* Pass all test, the value is valid, return true.  */
+	  return true;
+	}
+      if (GET_MODE_SIZE (outer_mode) == 4
+	  && NDS32_SINGLE_WORD_ALIGN_P (INTVAL (index)))
+	{
+	  /* Further check if the value is legal for the 'outer_mode'.  */
+	  if (!satisfies_constraint_Is17 (index))
+	    return false;
+
+	  /* Pass all test, the value is valid, return true.  */
+	  return true;
+	}
+      if (GET_MODE_SIZE (outer_mode) == 8
+	  && NDS32_SINGLE_WORD_ALIGN_P (INTVAL (index)))
+	{
+	  /* Further check if the value is legal for the 'outer_mode'.  */
+	  if (!satisfies_constraint_Is17 (gen_int_mode (INTVAL (index) + 4,
+							SImode)))
+	    return false;
+
+	  /* Pass all test, the value is valid, return true.  */
+	  return true;
+	}
+
+      return false;
+
+    case MULT:
+      op0 = XEXP (index, 0);
+      op1 = XEXP (index, 1);
+
+      if (REG_P (op0) && CONST_INT_P (op1))
+	{
+	  int multiplier;
+	  multiplier = INTVAL (op1);
+
+	  /* We only allow (mult reg const_int_1)
+	     or (mult reg const_int_2) or (mult reg const_int_4).  */
+	  if (multiplier != 1 && multiplier != 2 && multiplier != 4)
+	    return false;
+
+	  regno = REGNO (op0);
+	  /* Limit it in general registers if we are
+	     in reload pass or after reload pass.  */
+	  if(strict)
+	    return REGNO_OK_FOR_INDEX_P (regno);
+	  else
+	    return true;
+	}
+
+      return false;
+
+    case ASHIFT:
+      op0 = XEXP (index, 0);
+      op1 = XEXP (index, 1);
+
+      if (REG_P (op0) && CONST_INT_P (op1))
+	{
+	  int sv;
+	  /* op1 is already the sv value for use to do left shift.  */
+	  sv = INTVAL (op1);
+
+	  /* We only allow (ashift reg const_int_0)
+	     or (ashift reg const_int_1) or (ashift reg const_int_2).  */
+	  if (sv != 0 && sv != 1 && sv !=2)
+	    return false;
+
+	  regno = REGNO (op0);
+	  /* Limit it in general registers if we are
+	     in reload pass or after reload pass.  */
+	  if(strict)
+	    return REGNO_OK_FOR_INDEX_P (regno);
+	  else
+	    return true;
+	}
+
+      return false;
+
+    default:
+      return false;
+    }
+}
+
+/* Function to expand builtin function for
+   '[(unspec_volatile [(reg)])]'.  */
+static rtx
+nds32_expand_builtin_null_ftype_reg (enum insn_code icode,
+				     tree exp, rtx target)
+{
+  /* Mapping:
+       ops[0] <--> value0 <--> arg0 */
+  struct expand_operand ops[1];
+  tree arg0;
+  rtx value0;
+
+  /* Grab the incoming arguments and extract its rtx.  */
+  arg0 = CALL_EXPR_ARG (exp, 0);
+  value0 = expand_normal (arg0);
+
+  /* Create operands.  */
+  create_input_operand (&ops[0], value0, TYPE_MODE (TREE_TYPE (arg0)));
+
+  /* Emit new instruction.  */
+  if (!maybe_expand_insn (icode, 1, ops))
+    error ("invalid argument to built-in function");
+
+  return target;
+}
+
+/* Function to expand builtin function for
+   '[(set (reg) (unspec_volatile [(imm)]))]'.  */
+static rtx
+nds32_expand_builtin_reg_ftype_imm (enum insn_code icode,
+				    tree exp, rtx target)
+{
+  /* Mapping:
+       ops[0] <--> target <--> exp
+       ops[1] <--> value0 <--> arg0 */
+  struct expand_operand ops[2];
+  tree arg0;
+  rtx value0;
+
+  /* Grab the incoming arguments and extract its rtx.  */
+  arg0 = CALL_EXPR_ARG (exp, 0);
+  value0 = expand_normal (arg0);
+
+  /* Create operands.  */
+  create_output_operand (&ops[0], target, TYPE_MODE (TREE_TYPE (exp)));
+  create_input_operand (&ops[1], value0, TYPE_MODE (TREE_TYPE (arg0)));
+
+  /* Emit new instruction.  */
+  if (!maybe_expand_insn (icode, 2, ops))
+    error ("invalid argument to built-in function");
+
+  return target;
+}
+
+/* Function to expand builtin function for
+   '[(unspec_volatile [(reg) (imm)])]' pattern.  */
+static rtx
+nds32_expand_builtin_null_ftype_reg_imm (enum insn_code icode,
+					 tree exp, rtx target)
+{
+  /* Mapping:
+       ops[0] <--> value0 <--> arg0
+       ops[1] <--> value1 <--> arg1 */
+  struct expand_operand ops[2];
+  tree arg0, arg1;
+  rtx value0, value1;
+
+  /* Grab the incoming arguments and extract its rtx.  */
+  arg0 = CALL_EXPR_ARG (exp, 0);
+  arg1 = CALL_EXPR_ARG (exp, 1);
+  value0 = expand_normal (arg0);
+  value1 = expand_normal (arg1);
+
+  /* Create operands.  */
+  create_input_operand (&ops[0], value0, TYPE_MODE (TREE_TYPE (arg0)));
+  create_input_operand (&ops[1], value1, TYPE_MODE (TREE_TYPE (arg1)));
+
+  /* Emit new instruction.  */
+  if (!maybe_expand_insn (icode, 2, ops))
+    error ("invalid argument to built-in function");
+
+  return target;
+}
+
+/* A helper function to return character based on byte size.  */
+static char
+nds32_byte_to_size (int byte)
+{
+  switch (byte)
+    {
+    case 4:
+      return 'w';
+    case 2:
+      return 'h';
+    case 1:
+      return 'b';
+    default:
+      /* Normally it should not be here.  */
+      gcc_unreachable ();
+    }
+}
+
+/* A helper function to check if this function should contain prologue.  */
+static int
+nds32_have_prologue_p (void)
+{
+  int i;
+
+  for (i = 0; i < 28; i++)
+    if (NDS32_REQUIRED_CALLEE_SAVED_P (i))
+      return 1;
+
+  return (flag_pic
+	  || NDS32_REQUIRED_CALLEE_SAVED_P (FP_REGNUM)
+	  || NDS32_REQUIRED_CALLEE_SAVED_P (LP_REGNUM));
+}
+
+/* ------------------------------------------------------------------------ */
+
+/* PART 3: Implement target hook stuff definitions.  */
+
+/* Register Classes.  */
+
+static unsigned char
+nds32_class_max_nregs (reg_class_t rclass ATTRIBUTE_UNUSED,
+		       enum machine_mode mode)
+{
+  /* Return the maximum number of consecutive registers
+     needed to represent "mode" in a register of "rclass".  */
+  return ((GET_MODE_SIZE (mode) + UNITS_PER_WORD - 1) / UNITS_PER_WORD);
+}
+
+static int
+nds32_register_priority (int hard_regno)
+{
+  /* Encourage to use r0-r7 for LRA when optimize for size.  */
+  if (optimize_size && hard_regno < 8)
+    return 4;
+  return 3;
+}
+
+
+/* Stack Layout and Calling Conventions.  */
+
+/* There are three kinds of pointer concepts using in GCC compiler:
+
+     frame pointer: A pointer to the first location of local variables.
+     stack pointer: A pointer to the top of a stack frame.
+     argument pointer: A pointer to the incoming arguments.
+
+   In nds32 target calling convention, we are using 8-byte alignment.
+   Besides, we would like to have each stack frame of a function includes:
+
+     [Block A]
+       1. previous hard frame pointer
+       2. return address
+       3. callee-saved registers
+       4. <padding bytes> (we will calculte in nds32_compute_stack_frame()
+                           and save it at
+                           cfun->machine->callee_saved_area_padding_bytes)
+
+     [Block B]
+       1. local variables
+       2. spilling location
+       3. <padding bytes> (it will be calculated by GCC itself)
+       4. incoming arguments
+       5. <padding bytes> (it will be calculated by GCC itself)
+
+     [Block C]
+       1. <padding bytes> (it will be calculated by GCC itself)
+       2. outgoing arguments
+
+   We 'wrap' these blocks together with
+   hard frame pointer ($r28) and stack pointer ($r31).
+   By applying the basic frame/stack/argument pointers concept,
+   the layout of a stack frame shoule be like this:
+
+                            |    |
+       old stack pointer ->  ----
+                            |    | \
+                            |    |   saved arguments for
+                            |    |   vararg functions
+                            |    | /
+      hard frame pointer ->   --
+      & argument pointer    |    | \
+                            |    |   previous hardware frame pointer
+                            |    |   return address
+                            |    |   callee-saved registers
+                            |    | /
+           frame pointer ->   --
+                            |    | \
+                            |    |   local variables
+                            |    |   and incoming arguments
+                            |    | /
+                              --
+                            |    | \
+                            |    |   outgoing
+                            |    |   arguments
+                            |    | /
+           stack pointer ->  ----
+
+  $SFP and $AP are used to represent frame pointer and arguments pointer,
+  which will be both eliminated as hard frame pointer.  */
+
+/* Eliminating Frame Pointer and Arg Pointer.  */
+
+static bool nds32_can_eliminate (const int from_reg, const int to_reg)
+{
+  if (from_reg == ARG_POINTER_REGNUM && to_reg == STACK_POINTER_REGNUM)
+    return true;
+
+  if (from_reg == ARG_POINTER_REGNUM && to_reg == HARD_FRAME_POINTER_REGNUM)
+    return true;
+
+  if (from_reg == FRAME_POINTER_REGNUM && to_reg == STACK_POINTER_REGNUM)
+    return true;
+
+  if (from_reg == FRAME_POINTER_REGNUM && to_reg == HARD_FRAME_POINTER_REGNUM)
+    return true;
+
+  return false;
+}
+
+/* Passing Arguments in Registers.  */
+
+static rtx
+nds32_function_arg (cumulative_args_t ca, enum machine_mode mode,
+		    const_tree type, bool named)
+{
+  CUMULATIVE_ARGS *cum = get_cumulative_args (ca);
+
+  /* The last time this hook is called,
+     it is called with MODE == VOIDmode.  */
+  if (mode == VOIDmode)
+    return NULL_RTX;
+
+  /* For nameless arguments, they are passed on the stack.  */
+  if (!named)
+    return NULL_RTX;
+
+  /* If there are still registers available, return it.  */
+  if (NDS32_ARG_PASS_IN_REG_P (cum->reg_offset, mode, type))
+    {
+      /* Pick up the next available register number.  */
+      return gen_rtx_REG (mode,
+			  NDS32_AVAILABLE_REGNUM_FOR_ARG (cum->reg_offset,
+							  mode,
+							  type));
+    }
+  else
+    {
+      /* No register available, return NULL_RTX.
+         The compiler will use stack to pass argument instead.  */
+      return NULL_RTX;
+    }
+}
+
+static void
+nds32_function_arg_advance (cumulative_args_t ca, enum machine_mode mode,
+			    const_tree type, bool named)
+{
+  CUMULATIVE_ARGS *cum = get_cumulative_args (ca);
+
+  /* Advance next register for use.
+     Only named argument could be advanced.  */
+  if (named)
+    {
+      cum->reg_offset
+	= NDS32_AVAILABLE_REGNUM_FOR_ARG (cum->reg_offset, mode, type)
+	  - NDS32_GPR_ARG_FIRST_REGNUM
+	  + NDS32_NEED_N_REGS_FOR_ARG (mode, type);
+    }
+}
+
+static unsigned int
+nds32_function_arg_boundary (enum machine_mode mode, const_tree type)
+{
+  return (nds32_needs_double_word_align (mode, type)
+	  ? NDS32_DOUBLE_WORD_ALIGNMENT
+	  : PARM_BOUNDARY);
+}
+
+/* How Scalar Function Values Are Returned.  */
+
+static rtx
+nds32_function_value (const_tree ret_type,
+		      const_tree fn_decl_or_type ATTRIBUTE_UNUSED,
+		      bool outgoing ATTRIBUTE_UNUSED)
+{
+  enum machine_mode mode;
+  int unsignedp;
+
+  mode = TYPE_MODE (ret_type);
+  unsignedp = TYPE_UNSIGNED (ret_type);
+
+  mode = promote_mode (ret_type, mode, &unsignedp);
+
+  return gen_rtx_REG (mode, NDS32_GPR_RET_FIRST_REGNUM);
+}
+
+static rtx
+nds32_libcall_value (enum machine_mode mode,
+		     const_rtx fun ATTRIBUTE_UNUSED)
+{
+  return gen_rtx_REG (mode, NDS32_GPR_RET_FIRST_REGNUM);
+}
+
+static bool
+nds32_function_value_regno_p (const unsigned int regno)
+{
+  return (regno == NDS32_GPR_RET_FIRST_REGNUM);
+}
+
+/* Function Entry and Exit.  */
+
+/* The content produced from this function
+   will be placed before prologue body.  */
+static void
+nds32_asm_function_prologue (FILE *file,
+			     HOST_WIDE_INT size ATTRIBUTE_UNUSED)
+{
+  int r;
+  const char *func_name;
+  tree attrs;
+  tree name;
+
+  /* All stack frame information is supposed to be
+     already computed when expanding prologue.
+     The result is in cfun->machine.
+     DO NOT call nds32_compute_stack_frame() here
+     because it may corrupt the essential information.  */
+
+  fprintf (file, "\t! BEGIN PROLOGUE\n");
+  fprintf (file, "\t!     fp needed: %d\n", frame_pointer_needed);
+  fprintf (file, "\t!  pretend_args: %d\n", cfun->machine->va_args_size);
+  fprintf (file, "\t!    local_size: %d\n", cfun->machine->local_size);
+  fprintf (file, "\t! out_args_size: %d\n", cfun->machine->out_args_size);
+
+  /* Use df_regs_ever_live_p() to detect if the register
+     is ever used in the current function.  */
+  fprintf (file, "\t! registers ever_live: ");
+  for (r = 0; r < 32; r++)
+    {
+      if (df_regs_ever_live_p (r))
+	fprintf (file, "%s, ", reg_names[r]);
+    }
+  fputc ('\n', file);
+
+  /* Display the attributes of this function.  */
+  fprintf (file, "\t! function attributes: ");
+  /* GCC build attributes list with reverse order,
+     so we use nreverse() to make it looks like
+     the order that user specifies.  */
+  attrs = nreverse (DECL_ATTRIBUTES (current_function_decl));
+
+  /* If there is no any attribute, print out "None".  */
+  if (!attrs)
+    fprintf (file, "None");
+
+  /* If there are some attributes, try if we need to
+     construct isr vector information.  */
+  func_name = IDENTIFIER_POINTER (DECL_NAME (current_function_decl));
+  nds32_construct_isr_vectors_information (attrs, func_name);
+
+  /* Display all attributes of this function.  */
+  while (attrs)
+    {
+      name = TREE_PURPOSE (attrs);
+      fprintf (file, "%s ", IDENTIFIER_POINTER (name));
+
+      /* Pick up the next attribute.  */
+      attrs = TREE_CHAIN (attrs);
+    }
+  fputc ('\n', file);
+}
+
+/* After rtl prologue has been expanded, this function is used.  */
+static void
+nds32_asm_function_end_prologue (FILE *file)
+{
+  fprintf (file, "\t! END PROLOGUE\n");
+
+  /* If frame pointer is NOT needed and -mfp-as-gp is issued,
+     we can generate special directive: ".omit_fp_begin"
+     to guide linker doing fp-as-gp optimization.
+     However, for a naked function, which means
+     it should not have prologue/epilogue,
+     using fp-as-gp still requires saving $fp by push/pop behavior and
+     there is no benefit to use fp-as-gp on such small function.
+     So we need to make sure this function is NOT naked as well.  */
+  if (!frame_pointer_needed
+      && !cfun->machine->naked_p
+      && cfun->machine->fp_as_gp_p)
+    {
+      fprintf (file, "\t! ----------------------------------------\n");
+      fprintf (file, "\t! Guide linker to do "
+		     "link time optimization: fp-as-gp\n");
+      fprintf (file, "\t! We add one more instruction to "
+		     "initialize $fp near to $gp location.\n");
+      fprintf (file, "\t! If linker fails to use fp-as-gp transformation,\n");
+      fprintf (file, "\t! this extra instruction should be "
+		     "eliminated at link stage.\n");
+      fprintf (file, "\t.omit_fp_begin\n");
+      fprintf (file, "\tla\t$fp,_FP_BASE_\n");
+      fprintf (file, "\t! ----------------------------------------\n");
+    }
+}
+
+/* Before rtl epilogue has been expanded, this function is used.  */
+static void
+nds32_asm_function_begin_epilogue (FILE *file)
+{
+  /* If frame pointer is NOT needed and -mfp-as-gp is issued,
+     we can generate special directive: ".omit_fp_end"
+     to claim fp-as-gp optimization range.
+     However, for a naked function,
+     which means it should not have prologue/epilogue,
+     using fp-as-gp still requires saving $fp by push/pop behavior and
+     there is no benefit to use fp-as-gp on such small function.
+     So we need to make sure this function is NOT naked as well.  */
+  if (!frame_pointer_needed
+      && !cfun->machine->naked_p
+      && cfun->machine->fp_as_gp_p)
+    {
+      fprintf (file, "\t! ----------------------------------------\n");
+      fprintf (file, "\t! Claim the range of fp-as-gp "
+		     "link time optimization\n");
+      fprintf (file, "\t.omit_fp_end\n");
+      fprintf (file, "\t! ----------------------------------------\n");
+    }
+
+  fprintf (file, "\t! BEGIN EPILOGUE\n");
+}
+
+/* The content produced from this function
+   will be placed after epilogue body.  */
+static void
+nds32_asm_function_epilogue (FILE *file,
+			     HOST_WIDE_INT size ATTRIBUTE_UNUSED)
+{
+  fprintf (file, "\t! END EPILOGUE\n");
+}
+
+static void
+nds32_asm_output_mi_thunk (FILE *file, tree thunk ATTRIBUTE_UNUSED,
+			   HOST_WIDE_INT delta,
+			   HOST_WIDE_INT vcall_offset ATTRIBUTE_UNUSED,
+			   tree function)
+{
+  int this_regno;
+
+  /* Make sure unwind info is emitted for the thunk if needed.  */
+  final_start_function (emit_barrier (), file, 1);
+
+  this_regno = (aggregate_value_p (TREE_TYPE (TREE_TYPE (function)), function)
+		? 1
+		: 0);
+
+  if (delta != 0)
+    {
+      if (satisfies_constraint_Is15 (GEN_INT (delta)))
+        {
+          fprintf (file, "\taddi\t$r%d, $r%d, %ld\n",
+		   this_regno, this_regno, delta);
+        }
+      else if (satisfies_constraint_Is20 (GEN_INT (delta)))
+        {
+          fprintf (file, "\tmovi\t$ta, %ld\n", delta);
+          fprintf (file, "\tadd\t$r%d, $r%d, $ta\n", this_regno, this_regno);
+        }
+      else
+        {
+          fprintf (file, "\tsethi\t$ta, hi20(%ld)\n", delta);
+          fprintf (file, "\tori\t$ta, $ta, lo12(%ld)\n", delta);
+          fprintf (file, "\tadd\t$r%d, $r%d, $ta\n", this_regno, this_regno);
+        }
+    }
+
+  fprintf (file, "\tb\t");
+  assemble_name (file, XSTR (XEXP (DECL_RTL (function), 0), 0));
+  fprintf (file, "\n");
+
+  final_end_function ();
+}
+
+/* Permitting tail calls.  */
+
+/* Determine whether we need to enable warning for function return check.  */
+static bool
+nds32_warn_func_return (tree decl)
+{
+/* Naked functions are implemented entirely in assembly, including the
+   return sequence, so suppress warnings about this.  */
+  return !nds32_naked_function_p (decl);
+}
+
+
+/* Implementing the Varargs Macros.  */
+
+static bool
+nds32_strict_argument_naming (cumulative_args_t ca ATTRIBUTE_UNUSED)
+{
+  /* Return true so that all the named arguments for FUNCTION_ARG have named=1.
+     If return false, for the variadic function, all named arguments EXCEPT
+     the last are treated as named.  */
+  return true;
+}
+
+
+/* Trampolines for Nested Functions.  */
+
+static void
+nds32_asm_trampoline_template (FILE *f)
+{
+  if (TARGET_REDUCED_REGS)
+    {
+      /* Trampoline is not supported on reduced-set registers yet.  */
+      sorry ("a nested function is not supported for reduced registers");
+    }
+  else
+    {
+      asm_fprintf (f, "\t! Trampoline code template\n");
+      asm_fprintf (f, "\t! This code fragment will be copied "
+		      "into stack on demand\n");
+
+      asm_fprintf (f, "\tmfusr\t$r16,$pc\n");
+      asm_fprintf (f, "\tlwi\t$r15,[$r16 + 20] "
+		      "! load nested function address\n");
+      asm_fprintf (f, "\tlwi\t$r16,[$r16 + 16] "
+		      "! load chain_value\n");
+      asm_fprintf (f, "\tjr\t$r15\n");
+    }
+
+  /* Preserve space ($pc + 16) for saving chain_value,
+     nds32_trampoline_init will fill the value in this slot.  */
+  asm_fprintf (f, "\t! space for saving chain_value\n");
+  assemble_aligned_integer (UNITS_PER_WORD, const0_rtx);
+
+  /* Preserve space ($pc + 20) for saving nested function address,
+     nds32_trampoline_init will fill the value in this slot.  */
+  asm_fprintf (f, "\t! space for saving nested function address\n");
+  assemble_aligned_integer (UNITS_PER_WORD, const0_rtx);
+}
+
+/* Emit RTL insns to initialize the variable parts of a trampoline.  */
+static void
+nds32_trampoline_init (rtx m_tramp, tree fndecl, rtx chain_value)
+{
+  int i;
+
+  /* Nested function address.  */
+  rtx fnaddr;
+  /* The memory rtx that is going to
+     be filled with chain_value.  */
+  rtx chain_value_mem;
+  /* The memory rtx that is going to
+     be filled with nested function address.  */
+  rtx nested_func_mem;
+
+  /* Start address of trampoline code in stack, for doing cache sync.  */
+  rtx sync_cache_addr;
+  /* Temporary register for sync instruction.  */
+  rtx tmp_reg;
+  /* Instruction-cache sync instruction,
+     requesting an argument as starting address.  */
+  rtx isync_insn;
+  /* For convenience reason of doing comparison.  */
+  int tramp_align_in_bytes;
+
+  /* Trampoline is not supported on reduced-set registers yet.  */
+  if (TARGET_REDUCED_REGS)
+    sorry ("a nested function is not supported for reduced registers");
+
+  /* STEP 1: Copy trampoline code template into stack,
+             fill up essential data into stack.  */
+
+  /* Extract nested function address rtx.  */
+  fnaddr = XEXP (DECL_RTL (fndecl), 0);
+
+  /* m_tramp is memory rtx that is going to be filled with trampoline code.
+     We have nds32_asm_trampoline_template() to emit template pattern.  */
+  emit_block_move (m_tramp, assemble_trampoline_template (),
+		   GEN_INT (TRAMPOLINE_SIZE), BLOCK_OP_NORMAL);
+
+  /* After copying trampoline code into stack,
+     fill chain_value into stack.  */
+  chain_value_mem = adjust_address (m_tramp, SImode, 16);
+  emit_move_insn (chain_value_mem, chain_value);
+  /* After copying trampoline code int stack,
+     fill nested function address into stack.  */
+  nested_func_mem = adjust_address (m_tramp, SImode, 20);
+  emit_move_insn (nested_func_mem, fnaddr);
+
+  /* STEP 2: Sync instruction-cache.  */
+
+  /* We have successfully filled trampoline code into stack.
+     However, in order to execute code in stack correctly,
+     we must sync instruction cache.  */
+  sync_cache_addr = XEXP (m_tramp, 0);
+  tmp_reg         = gen_reg_rtx (SImode);
+  isync_insn      = gen_unspec_volatile_isync (tmp_reg);
+
+  /* Because nds32_cache_block_size is in bytes,
+     we get trampoline alignment in bytes for convenient comparison.  */
+  tramp_align_in_bytes = TRAMPOLINE_ALIGNMENT / BITS_PER_UNIT;
+
+  if (tramp_align_in_bytes >= nds32_cache_block_size
+      && (tramp_align_in_bytes % nds32_cache_block_size) == 0)
+    {
+      /* Under this condition, the starting address of trampoline
+         must be aligned to the starting address of each cache block
+         and we do not have to worry about cross-boundary issue.  */
+      for (i = 0;
+	   i < (TRAMPOLINE_SIZE + nds32_cache_block_size - 1)
+	       / nds32_cache_block_size;
+	   i++)
+	{
+	  emit_move_insn (tmp_reg,
+			  plus_constant (Pmode, sync_cache_addr,
+					 nds32_cache_block_size * i));
+	  emit_insn (isync_insn);
+	}
+    }
+  else if (TRAMPOLINE_SIZE > nds32_cache_block_size)
+    {
+      /* The starting address of trampoline code
+         may not be aligned to the cache block,
+         so the trampoline code may be across two cache block.
+         We need to sync the last element, which is 4-byte size,
+         of trampoline template.  */
+      for (i = 0;
+	   i < (TRAMPOLINE_SIZE + nds32_cache_block_size - 1)
+	       / nds32_cache_block_size;
+	   i++)
+	{
+	  emit_move_insn (tmp_reg,
+			  plus_constant (Pmode, sync_cache_addr,
+					 nds32_cache_block_size * i));
+	  emit_insn (isync_insn);
+	}
+
+      /* The last element of trampoline template is 4-byte size.  */
+      emit_move_insn (tmp_reg,
+		      plus_constant (Pmode, sync_cache_addr,
+				     TRAMPOLINE_SIZE - 4));
+      emit_insn (isync_insn);
+    }
+  else
+    {
+      /* This is the simplest case.
+         Because TRAMPOLINE_SIZE is less than or
+         equal to nds32_cache_block_size,
+         we can just sync start address and
+         the last element of trampoline code.  */
+
+      /* Sync starting address of tampoline code.  */
+      emit_move_insn (tmp_reg, sync_cache_addr);
+      emit_insn (isync_insn);
+      /* Sync the last element, which is 4-byte size,
+         of trampoline template.  */
+      emit_move_insn (tmp_reg,
+		      plus_constant (Pmode, sync_cache_addr,
+				     TRAMPOLINE_SIZE - 4));
+      emit_insn (isync_insn);
+    }
+
+  /* Set instruction serialization barrier
+     to guarantee the correct operations.  */
+  emit_insn (gen_unspec_volatile_isb ());
+}
+
+
+/* Addressing Modes.  */
+
+static bool
+nds32_legitimate_address_p (enum machine_mode mode, rtx x, bool strict)
+{
+  /* For (mem:DI addr) or (mem:DF addr) case,
+     we only allow 'addr' to be [reg], [symbol_ref],
+                                [const], or [reg + const_int] pattern.  */
+  if (mode == DImode || mode == DFmode)
+    {
+      /* Allow [Reg + const_int] addressing mode.  */
+      if (GET_CODE (x) == PLUS)
+	{
+	  if (nds32_address_register_rtx_p (XEXP (x, 0), strict)
+	      && nds32_legitimate_index_p (mode, XEXP (x, 1), strict)
+	      && CONST_INT_P (XEXP (x, 1)))
+	    return true;
+
+	  else if (nds32_address_register_rtx_p (XEXP (x, 1), strict)
+		   && nds32_legitimate_index_p (mode, XEXP (x, 0), strict)
+		   && CONST_INT_P (XEXP (x, 0)))
+	    return true;
+	}
+
+      /* Now check [reg], [symbol_ref], and [const].  */
+      if (GET_CODE (x) != REG
+	  && GET_CODE (x) != SYMBOL_REF
+	  && GET_CODE (x) != CONST)
+	return false;
+    }
+
+  /* Check if 'x' is a valid address.  */
+  switch (GET_CODE (x))
+    {
+    case REG:
+      /* (mem (reg A)) => [Ra] */
+      return nds32_address_register_rtx_p (x, strict);
+
+    case SYMBOL_REF:
+
+      if (!TARGET_GP_DIRECT
+	  && (reload_completed
+	      || reload_in_progress
+	      || lra_in_progress))
+	return false;
+
+      /* (mem (symbol_ref A)) => [symbol_ref] */
+      return !currently_expanding_to_rtl;
+
+    case CONST:
+
+      if (!TARGET_GP_DIRECT
+	  && (reload_completed
+	      || reload_in_progress
+	      || lra_in_progress))
+	return false;
+
+      /* (mem (const (...)))
+         => [ + const_addr ], where const_addr = symbol_ref + const_int */
+      if (GET_CODE (XEXP (x, 0)) == PLUS)
+	{
+	  rtx plus_op = XEXP (x, 0);
+
+	  rtx op0 = XEXP (plus_op, 0);
+	  rtx op1 = XEXP (plus_op, 1);
+
+	  if (GET_CODE (op0) == SYMBOL_REF && CONST_INT_P (op1))
+	    return true;
+	  else
+	    return false;
+	}
+
+	return false;
+
+    case POST_MODIFY:
+      /* (mem (post_modify (reg) (plus (reg) (reg))))
+         => [Ra], Rb */
+      /* (mem (post_modify (reg) (plus (reg) (const_int))))
+         => [Ra], const_int */
+      if (GET_CODE (XEXP (x, 0)) == REG
+	  && GET_CODE (XEXP (x, 1)) == PLUS)
+	{
+	  rtx plus_op = XEXP (x, 1);
+
+	  rtx op0 = XEXP (plus_op, 0);
+	  rtx op1 = XEXP (plus_op, 1);
+
+	  if (nds32_address_register_rtx_p (op0, strict)
+	      && nds32_legitimate_index_p (mode, op1, strict))
+	    return true;
+	  else
+	    return false;
+	}
+
+	return false;
+
+    case POST_INC:
+    case POST_DEC:
+      /* (mem (post_inc reg)) => [Ra], 1/2/4 */
+      /* (mem (post_dec reg)) => [Ra], -1/-2/-4 */
+      /* The 1/2/4 or -1/-2/-4 have been displayed in nds32.md.
+         We only need to deal with register Ra.  */
+      if (nds32_address_register_rtx_p (XEXP (x, 0), strict))
+	return true;
+      else
+	return false;
+
+    case PLUS:
+      /* (mem (plus reg const_int))
+         => [Ra + imm] */
+      /* (mem (plus reg reg))
+         => [Ra + Rb] */
+      /* (mem (plus (mult reg const_int) reg))
+         => [Ra + Rb << sv] */
+      if (nds32_address_register_rtx_p (XEXP (x, 0), strict)
+	  && nds32_legitimate_index_p (mode, XEXP (x, 1), strict))
+	return true;
+      else if (nds32_address_register_rtx_p (XEXP (x, 1), strict)
+	       && nds32_legitimate_index_p (mode, XEXP (x, 0), strict))
+	return true;
+      else
+	return false;
+
+    case LO_SUM:
+      if (!TARGET_GP_DIRECT)
+	return true;
+
+    default:
+      return false;
+    }
+}
+
+
+/* Describing Relative Costs of Operations.  */
+
+static int nds32_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
+				     reg_class_t from,
+				     reg_class_t to)
+{
+  if (from == HIGH_REGS || to == HIGH_REGS)
+    return 6;
+
+  return 2;
+}
+
+static int nds32_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
+				   reg_class_t rclass ATTRIBUTE_UNUSED,
+				   bool in ATTRIBUTE_UNUSED)
+{
+  return 8;
+}
+
+/* This target hook describes the relative costs of RTL expressions.
+   Return 'true' when all subexpressions of x have been processed.
+   Return 'false' to sum the costs of sub-rtx, plus cost of this operation.
+   Refer to gcc/rtlanal.c for more information.  */
+static bool
+nds32_rtx_costs (rtx x,
+		 int code,
+		 int outer_code,
+		 int opno ATTRIBUTE_UNUSED,
+		 int *total,
+		 bool speed)
+{
+  /* According to 'speed', goto suitable cost model section.  */
+  if (speed)
+    goto performance_cost;
+  else
+    goto size_cost;
+
+
+performance_cost:
+  /* This is section for performance cost model.  */
+
+  /* In gcc/rtl.h, the default value of COSTS_N_INSNS(N) is N*4.
+     We treat it as 4-cycle cost for each instruction
+     under performance consideration.  */
+  switch (code)
+    {
+    case SET:
+      /* For 'SET' rtx, we need to return false
+         so that it can recursively calculate costs.  */
+      return false;
+
+    case USE:
+      /* Used in combine.c as a marker.  */
+      *total = 0;
+      break;
+
+    case MULT:
+      *total = COSTS_N_INSNS (5);
+      break;
+
+    case DIV:
+    case UDIV:
+    case MOD:
+    case UMOD:
+      *total = COSTS_N_INSNS (7);
+      break;
+
+    default:
+      *total = COSTS_N_INSNS (1);
+      break;
+    }
+
+  return true;
+
+
+size_cost:
+  /* This is section for size cost model.  */
+
+  /* In gcc/rtl.h, the default value of COSTS_N_INSNS(N) is N*4.
+     We treat it as 4-byte cost for each instruction
+     under code size consideration.  */
+  switch (code)
+    {
+    case SET:
+      /* For 'SET' rtx, we need to return false
+         so that it can recursively calculate costs.  */
+      return false;
+
+    case USE:
+      /* Used in combine.c as a marker.  */
+      *total = 0;
+      break;
+
+    case CONST_INT:
+      /* All instructions involving constant operation
+         need to be considered for cost evaluation.  */
+      if (outer_code == SET)
+	{
+	  /* (set X imm5s), use movi55, 2-byte cost.
+	     (set X imm20s), use movi, 4-byte cost.
+	     (set X BIG_INT), use sethi/ori, 8-byte cost.  */
+	  if (satisfies_constraint_Is05 (x))
+	    *total = COSTS_N_INSNS (1) - 2;
+	  else if (satisfies_constraint_Is20 (x))
+	    *total = COSTS_N_INSNS (1);
+	  else
+	    *total = COSTS_N_INSNS (2);
+	}
+      else if (outer_code == PLUS || outer_code == MINUS)
+	{
+	  /* Possible addi333/subi333 or subi45/addi45, 2-byte cost.
+	     General case, cost 1 instruction with 4-byte.  */
+	  if (satisfies_constraint_Iu05 (x))
+	    *total = COSTS_N_INSNS (1) - 2;
+	  else
+	    *total = COSTS_N_INSNS (1);
+	}
+      else if (outer_code == ASHIFT)
+	{
+	  /* Possible slli333, 2-byte cost.
+	     General case, cost 1 instruction with 4-byte.  */
+	  if (satisfies_constraint_Iu03 (x))
+	    *total = COSTS_N_INSNS (1) - 2;
+	  else
+	    *total = COSTS_N_INSNS (1);
+	}
+      else if (outer_code == ASHIFTRT || outer_code == LSHIFTRT)
+	{
+	  /* Possible srai45 or srli45, 2-byte cost.
+	     General case, cost 1 instruction with 4-byte.  */
+	  if (satisfies_constraint_Iu05 (x))
+	    *total = COSTS_N_INSNS (1) - 2;
+	  else
+	    *total = COSTS_N_INSNS (1);
+	}
+      else
+	{
+	  /* For other cases, simply set it 4-byte cost.  */
+	  *total = COSTS_N_INSNS (1);
+	}
+      break;
+
+    case CONST_DOUBLE:
+      /* It requires high part and low part processing, set it 8-byte cost.  */
+      *total = COSTS_N_INSNS (2);
+      break;
+
+    default:
+      /* For other cases, generally we set it 4-byte cost
+         and stop resurively traversing.  */
+      *total = COSTS_N_INSNS (1);
+      break;
+    }
+
+  return true;
+}
+
+static int nds32_address_cost (rtx address,
+			       enum machine_mode mode ATTRIBUTE_UNUSED,
+			       addr_space_t as ATTRIBUTE_UNUSED,
+			       bool speed)
+{
+  rtx plus0, plus1;
+  enum rtx_code code;
+
+  code = GET_CODE (address);
+
+  /* According to 'speed', goto suitable cost model section.  */
+  if (speed)
+    goto performance_cost;
+  else
+    goto size_cost;
+
+performance_cost:
+  /* This is section for performance cost model.  */
+
+  /* FALLTHRU, currently we use same cost model as size_cost.  */
+
+size_cost:
+  /* This is section for size cost model.  */
+
+  switch (code)
+    {
+    case POST_MODIFY:
+    case POST_INC:
+    case POST_DEC:
+      /* We encourage that rtx contains
+         POST_MODIFY/POST_INC/POST_DEC behavior.  */
+      return 0;
+
+    case SYMBOL_REF:
+      /* We can have gp-relative load/store for symbol_ref.
+         Have it 4-byte cost.  */
+      return COSTS_N_INSNS (1);
+
+    case CONST:
+      /* It is supposed to be the pattern (const (plus symbol_ref const_int)).
+         Have it 4-byte cost.  */
+      return COSTS_N_INSNS (1);
+
+    case REG:
+      /* Simply return 4-byte costs.  */
+      return COSTS_N_INSNS (1);
+
+    case PLUS:
+      /* We do not need to check if the address is a legitimate address,
+         because this hook is never called with an invalid address.
+         But we better check the range of
+         const_int value for cost, if it exists.  */
+      plus0 = XEXP (address, 0);
+      plus1 = XEXP (address, 1);
+
+      if (REG_P (plus0) && CONST_INT_P (plus1))
+        {
+	  /* If it is possible to be lwi333/swi333 form,
+	     make it 2-byte cost.  */
+	  if (satisfies_constraint_Iu05 (plus1))
+	    return (COSTS_N_INSNS (1) - 2);
+	  else
+	    return COSTS_N_INSNS (1);
+	}
+
+      /* For other 'plus' situation, make it cost 4-byte.  */
+      return COSTS_N_INSNS (1);
+
+    default:
+      break;
+    }
+
+  return COSTS_N_INSNS (4);
+}
+
+
+/* Defining the Output Assembler Language.  */
+
+/* The Overall Framework of an Assembler File.  */
+
+static void
+nds32_asm_file_start (void)
+{
+  int i;
+
+  default_file_start ();
+
+  /* Tell assembler that this asm code is generated by compiler.  */
+  fprintf (asm_out_file, "\t! This asm file is generated by compiler\n");
+  fprintf (asm_out_file, "\t.flag\tverbatim\n");
+  /* Give assembler the size of each vector for interrupt handler.  */
+  fprintf (asm_out_file, "\t! This vector size directive is required "
+			 "for checking inconsistency on interrupt handler\n");
+  fprintf (asm_out_file, "\t.vec_size\t%d\n", nds32_isr_vector_size);
+
+  /* If user enables '-mforce-fp-as-gp' or compiles programs with -Os,
+     the compiler may produce 'la $fp,_FP_BASE_' instruction
+     at prologue for fp-as-gp optimization.
+     We should emit weak reference of _FP_BASE_ to avoid undefined reference
+     in case user does not pass '--relax' option to linker.  */
+  if (TARGET_FORCE_FP_AS_GP || optimize_size)
+    {
+      fprintf (asm_out_file, "\t! This weak reference is required to do "
+			     "fp-as-gp link time optimization\n");
+      fprintf (asm_out_file, "\t.weak\t_FP_BASE_\n");
+    }
+  /* If user enables '-mex9', we should emit relaxation directive
+     to tell linker that this file is allowed to do ex9 optimization.  */
+  if (TARGET_EX9)
+    {
+      fprintf (asm_out_file, "\t! This relaxation directive is required "
+			     "to do ex9 link time optimization\n");
+      fprintf (asm_out_file, "\t.relax\tex9\n");
+    }
+
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+
+  if (TARGET_ISA_V2)
+    fprintf (asm_out_file, "\t! ISA family\t\t: %s\n", "V2");
+  if (TARGET_ISA_V3)
+    fprintf (asm_out_file, "\t! ISA family\t\t: %s\n", "V3");
+  if (TARGET_ISA_V3M)
+    fprintf (asm_out_file, "\t! ISA family\t\t: %s\n", "V3M");
+
+  fprintf (asm_out_file, "\t! Endian setting\t: %s\n",
+			 ((TARGET_BIG_ENDIAN) ? "big-endian"
+					      : "little-endian"));
+
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+
+  fprintf (asm_out_file, "\t! Use conditional move\t\t: %s\n",
+			 ((TARGET_CMOV) ? "Yes"
+					: "No"));
+  fprintf (asm_out_file, "\t! Use performance extension\t: %s\n",
+			 ((TARGET_PERF_EXT) ? "Yes"
+					    : "No"));
+
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+
+  fprintf (asm_out_file, "\t! V3PUSH instructions\t: %s\n",
+			 ((TARGET_V3PUSH) ? "Yes"
+					  : "No"));
+  fprintf (asm_out_file, "\t! 16-bit instructions\t: %s\n",
+			 ((TARGET_16_BIT) ? "Yes"
+					  : "No"));
+  fprintf (asm_out_file, "\t! GP base access\t: %s\n",
+			 ((TARGET_GP_DIRECT) ? "Yes"
+					     : "No"));
+  fprintf (asm_out_file, "\t! Reduced registers set\t: %s\n",
+			 ((TARGET_REDUCED_REGS) ? "Yes"
+						: "No"));
+
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+
+  if (optimize_size)
+    fprintf (asm_out_file, "\t! Optimization level\t: -Os\n");
+  else
+    fprintf (asm_out_file, "\t! Optimization level\t: -O%d\n", optimize);
+
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+
+  fprintf (asm_out_file, "\t! Cache block size\t: %d\n",
+			 nds32_cache_block_size);
+
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+
+  /* Initialize isr vector information array before compiling functions.  */
+  for (i = 0; i < NDS32_N_ISR_VECTORS; i++)
+    {
+      nds32_isr_vectors[i].category = NDS32_ISR_NONE;
+      strcpy (nds32_isr_vectors[i].func_name, "");
+      nds32_isr_vectors[i].save_reg = NDS32_PARTIAL_SAVE;
+      nds32_isr_vectors[i].nested_type = NDS32_NOT_NESTED;
+      nds32_isr_vectors[i].total_n_vectors = 0;
+      strcpy (nds32_isr_vectors[i].nmi_name, "");
+      strcpy (nds32_isr_vectors[i].warm_name, "");
+    }
+}
+
+static void
+nds32_asm_file_end (void)
+{
+  int i;
+
+  /* If all the vectors are NDS32_ISR_NONE, we can return immediately.  */
+  for (i = 0; i < NDS32_N_ISR_VECTORS; i++)
+    if (nds32_isr_vectors[i].category != NDS32_ISR_NONE)
+      break;
+
+  if (i == NDS32_N_ISR_VECTORS)
+    return;
+
+  /* At least one vector is NOT NDS32_ISR_NONE,
+     we should output isr vector information.  */
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+  fprintf (asm_out_file, "\t! The isr vector information:\n");
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+
+  /* Check reset handler first.  Its vector number is always 0.  */
+  if (nds32_isr_vectors[0].category == NDS32_ISR_RESET)
+    {
+      nds32_emit_isr_reset_content ();
+      fprintf (asm_out_file, "\t! ------------------------------------\n");
+    }
+
+  /* Check other vectors, starting from vector number 1.  */
+  for (i = 1; i < NDS32_N_ISR_VECTORS; i++)
+    {
+      if (nds32_isr_vectors[i].category == NDS32_ISR_INTERRUPT
+	  || nds32_isr_vectors[i].category == NDS32_ISR_EXCEPTION)
+	{
+	  /* Found one vector which is interupt or exception.
+	     Output its jmptbl and vector section content.  */
+	  fprintf (asm_out_file, "\t! interrupt/exception vector %02d\n", i);
+	  fprintf (asm_out_file, "\t! ------------------------------------\n");
+	  nds32_emit_isr_jmptbl_section (i);
+	  fprintf (asm_out_file, "\t! ....................................\n");
+	  nds32_emit_isr_vector_section (i);
+	  fprintf (asm_out_file, "\t! ------------------------------------\n");
+	}
+    }
+
+  fprintf (asm_out_file, "\t! ------------------------------------\n");
+}
+
+/* Output and Generation of Labels.  */
+
+static void
+nds32_asm_globalize_label (FILE *stream, const char *name)
+{
+  fputs ("\t.global\t", stream);
+  assemble_name (stream, name);
+  fputs ("\n", stream);
+}
+
+/* Output of Assembler Instructions.  */
+
+static void
+nds32_print_operand (FILE *stream, rtx x, int code)
+{
+  int op_value;
+
+  switch (code)
+    {
+    case 0 :
+      /* Do nothing special.  */
+      break;
+
+    case 'V':
+      /* 'x' is supposed to be CONST_INT, get the value.  */
+      gcc_assert (CONST_INT_P (x));
+      op_value = INTVAL (x);
+
+      /* According to the Andes architecture,
+         the system/user register index range is 0 ~ 1023.
+         In order to avoid conflict between user-specified-integer value
+         and enum-specified-register value,
+         the 'enum nds32_intrinsic_registers' value
+         in nds32_intrinsic.h starts from 1024.  */
+      if (op_value < 1024 && op_value >= 0)
+	{
+	  /* If user gives integer value directly (0~1023),
+	     we just print out the value.  */
+	  fprintf (stream, "%d", op_value);
+	}
+      else if (op_value < 0
+	       || op_value >= ((int) ARRAY_SIZE (nds32_intrinsic_register_names)
+			       + 1024))
+	{
+	  /* The enum index value for array size is out of range.  */
+	  error ("intrinsic register index is out of range");
+	}
+      else
+	{
+	  /* If user applies normal way with __NDS32_REG_XXX__ enum data,
+	     we can print out register name.  Remember to substract 1024.  */
+	  fprintf (stream, "%s",
+			   nds32_intrinsic_register_names[op_value - 1024]);
+	}
+
+      /* No need to handle following process, so return immediately.  */
+      return;
+
+    default :
+      /* Unknown flag.  */
+      output_operand_lossage ("invalid operand output code");
+      break;
+    }
+
+  switch (GET_CODE (x))
+    {
+    case LABEL_REF:
+    case SYMBOL_REF:
+      output_addr_const (stream, x);
+      break;
+
+    case REG:
+      /* Forbid using static chain register ($r16)
+         on reduced-set registers configuration.  */
+      if (TARGET_REDUCED_REGS
+	  && REGNO (x) == STATIC_CHAIN_REGNUM)
+	sorry ("a nested function is not supported for reduced registers");
+
+      /* Normal cases, print out register name.  */
+      fputs (reg_names[REGNO (x)], stream);
+      break;
+
+    case MEM:
+      output_address (XEXP (x, 0));
+      break;
+
+    case CODE_LABEL:
+    case CONST_INT:
+    case CONST:
+      output_addr_const (stream, x);
+      break;
+
+    default:
+      /* Generally, output_addr_const () is able to handle most cases.
+         We want to see what CODE could appear,
+         so we use gcc_unreachable() to stop it.  */
+      debug_rtx (x);
+      gcc_unreachable ();
+      break;
+    }
+}
+
+static void
+nds32_print_operand_address (FILE *stream, rtx x)
+{
+  rtx op0, op1;
+
+  switch (GET_CODE (x))
+    {
+    case SYMBOL_REF:
+    case CONST:
+      /* [ + symbol_ref] */
+      /* [ + const_addr], where const_addr = symbol_ref + const_int */
+      fputs ("[ + ", stream);
+      output_addr_const (stream, x);
+      fputs ("]", stream);
+      break;
+
+    case REG:
+      /* Forbid using static chain register ($r16)
+         on reduced-set registers configuration.  */
+      if (TARGET_REDUCED_REGS
+	  && REGNO (x) == STATIC_CHAIN_REGNUM)
+	sorry ("a nested function is not supported for reduced registers");
+
+      /* [Ra] */
+      fprintf (stream, "[%s]", reg_names[REGNO (x)]);
+      break;
+
+    case PLUS:
+      op0 = XEXP (x, 0);
+      op1 = XEXP (x, 1);
+
+      /* Checking op0, forbid using static chain register ($r16)
+         on reduced-set registers configuration.  */
+      if (TARGET_REDUCED_REGS
+	  && REG_P (op0)
+	  && REGNO (op0) == STATIC_CHAIN_REGNUM)
+	sorry ("a nested function is not supported for reduced registers");
+      /* Checking op1, forbid using static chain register ($r16)
+         on reduced-set registers configuration.  */
+      if (TARGET_REDUCED_REGS
+	  && REG_P (op1)
+	  && REGNO (op1) == STATIC_CHAIN_REGNUM)
+	sorry ("a nested function is not supported for reduced registers");
+
+      if (REG_P (op0) && CONST_INT_P (op1))
+	{
+	  /* [Ra + imm] */
+	  fprintf (stream, "[%s + (%d)]",
+			   reg_names[REGNO (op0)], (int)INTVAL (op1));
+	}
+      else if (REG_P (op0) && REG_P (op1))
+	{
+	  /* [Ra + Rb] */
+	  fprintf (stream, "[%s + %s]",
+			   reg_names[REGNO (op0)], reg_names[REGNO (op1)]);
+	}
+      else if (GET_CODE (op0) == MULT && REG_P (op1))
+	{
+	  /* [Ra + Rb << sv]
+	     From observation, the pattern looks like:
+	     (plus:SI (mult:SI (reg:SI 58)
+	                       (const_int 4 [0x4]))
+	              (reg/f:SI 57)) */
+	  int sv;
+
+	  /* We need to set sv to output shift value.  */
+	  if (INTVAL (XEXP (op0, 1)) == 1)
+	    sv = 0;
+	  else if (INTVAL (XEXP (op0, 1)) == 2)
+	    sv = 1;
+	  else if (INTVAL (XEXP (op0, 1)) == 4)
+	    sv = 2;
+	  else
+	    gcc_unreachable ();
+
+	  fprintf (stream, "[%s + %s << %d]",
+			   reg_names[REGNO (op1)],
+			   reg_names[REGNO (XEXP (op0, 0))],
+			   sv);
+	}
+      else
+	{
+	  /* The control flow is not supposed to be here.  */
+	  debug_rtx (x);
+	  gcc_unreachable ();
+	}
+
+      break;
+
+    case POST_MODIFY:
+      /* (post_modify (regA) (plus (regA) (regB)))
+         (post_modify (regA) (plus (regA) (const_int)))
+         We would like to extract
+         regA and regB (or const_int) from plus rtx.  */
+      op0 = XEXP (XEXP (x, 1), 0);
+      op1 = XEXP (XEXP (x, 1), 1);
+
+      /* Checking op0, forbid using static chain register ($r16)
+         on reduced-set registers configuration.  */
+      if (TARGET_REDUCED_REGS
+	  && REG_P (op0)
+	  && REGNO (op0) == STATIC_CHAIN_REGNUM)
+	sorry ("a nested function is not supported for reduced registers");
+      /* Checking op1, forbid using static chain register ($r16)
+         on reduced-set registers configuration.  */
+      if (TARGET_REDUCED_REGS
+	  && REG_P (op1)
+	  && REGNO (op1) == STATIC_CHAIN_REGNUM)
+	sorry ("a nested function is not supported for reduced registers");
+
+      if (REG_P (op0) && REG_P (op1))
+	{
+	  /* [Ra], Rb */
+	  fprintf (stream, "[%s], %s",
+			   reg_names[REGNO (op0)], reg_names[REGNO (op1)]);
+	}
+      else if (REG_P (op0) && CONST_INT_P (op1))
+	{
+	  /* [Ra], imm */
+	  fprintf (stream, "[%s], %d",
+			   reg_names[REGNO (op0)], (int)INTVAL (op1));
+	}
+      else
+	{
+	  /* The control flow is not supposed to be here.  */
+	  debug_rtx (x);
+	  gcc_unreachable ();
+	}
+
+      break;
+
+    case POST_INC:
+    case POST_DEC:
+      op0 = XEXP (x, 0);
+
+      /* Checking op0, forbid using static chain register ($r16)
+         on reduced-set registers configuration.  */
+      if (TARGET_REDUCED_REGS
+	  && REG_P (op0)
+	  && REGNO (op0) == STATIC_CHAIN_REGNUM)
+	sorry ("a nested function is not supported for reduced registers");
+
+      if (REG_P (op0))
+	{
+	  /* "[Ra], 1/2/4" or "[Ra], -1/-2/-4"
+	     The 1/2/4 or -1/-2/-4 have been displayed in nds32.md.
+	     We only need to deal with register Ra.  */
+	  fprintf (stream, "[%s]", reg_names[REGNO (op0)]);
+	}
+      else
+	{
+	  /* The control flow is not supposed to be here.  */
+	  debug_rtx (x);
+	  gcc_unreachable ();
+	}
+
+      break;
+
+    default :
+      /* Generally, output_addr_const () is able to handle most cases.
+         We want to see what CODE could appear,
+         so we use gcc_unreachable() to stop it.  */
+      debug_rtx (x);
+      gcc_unreachable ();
+      break;
+    }
+}
+
+
+/* Defining target-specific uses of __attribute__.  */
+
+/* Add some checking after merging attributes.  */
+static tree
+nds32_merge_decl_attributes (tree olddecl, tree newdecl)
+{
+  const char *func_name;
+  tree combined_attrs;
+
+  /* Create combined attributes.  */
+  combined_attrs = merge_attributes (DECL_ATTRIBUTES (olddecl),
+				     DECL_ATTRIBUTES (newdecl));
+
+  /* Sinc newdecl is acutally a duplicate of olddecl,
+     we can take olddecl for some operations.  */
+  if (TREE_CODE (olddecl) == FUNCTION_DECL)
+    {
+      /* Extract function name.  Since newdecl is actually a duplicate
+         of olddecl, we can use olddecl to get the name string.  */
+      func_name = IDENTIFIER_POINTER (DECL_NAME (olddecl));
+
+      /* Check isr-specific attributes conflict.  */
+      nds32_check_isr_attrs_conflict (func_name, combined_attrs);
+    }
+
+  return combined_attrs;
+}
+
+/* Add some checking when inserting attributes.  */
+static void
+nds32_insert_attributes (tree decl, tree *attributes)
+{
+  /* For function declaration, we need to check isr-specific attributes:
+       1. Call nds32_check_isr_attrs_conflict() to check any conflict.
+       2. Check valid integer value for interrupt/exception.
+       3. Check valid integer value for reset.
+       4. Check valid function for nmi/warm.  */
+  if (TREE_CODE (decl) == FUNCTION_DECL)
+    {
+      const char *func_name;
+      tree func_attrs;
+      tree intr, excp, reset;
+
+      /* Extract function name.  */
+      func_name = IDENTIFIER_POINTER (DECL_NAME (decl));
+      /* Pick up function attributes.  */
+      func_attrs = *attributes;
+
+      /* 1. Call nds32_check_isr_attrs_conflict() to check any conflict.  */
+      nds32_check_isr_attrs_conflict (func_name, func_attrs);
+
+      /* Now we are starting to check valid id value
+         for interrupt/exception/reset.
+         Note that we ONLY check its validity here.
+         To construct isr vector information, it is still performed
+         by nds32_construct_isr_vectors_information().  */
+      intr  = lookup_attribute ("interrupt", func_attrs);
+      excp  = lookup_attribute ("exception", func_attrs);
+      reset = lookup_attribute ("reset", func_attrs);
+
+      if (intr || excp)
+	{
+	  /* Deal with interrupt/exception.  */
+	  tree id_list;
+	  unsigned int lower_bound, upper_bound;
+
+	  /* The way to handle interrupt or exception is the same,
+	     we just need to take care of actual vector number.
+	     For interrupt(0..63), the actual vector number is (9..72).
+	     For exception(1..8), the actual vector number is (1..8).  */
+	  lower_bound = (intr) ? (0) : (1);
+	  upper_bound = (intr) ? (63) : (8);
+
+	  /* Prepare id list so that we can traverse id value.  */
+	  id_list = (intr) ? (TREE_VALUE (intr)) : (TREE_VALUE (excp));
+
+	  /* 2. Check valid integer value for interrupt/exception.  */
+	  while (id_list)
+	    {
+	      tree id;
+
+	      /* Pick up each vector id value.  */
+	      id = TREE_VALUE (id_list);
+	      /* Issue error if it is not a valid integer value.  */
+	      if (TREE_CODE (id) != INTEGER_CST
+		  || TREE_INT_CST_LOW (id) < lower_bound
+		  || TREE_INT_CST_LOW (id) > upper_bound)
+		error ("invalid id value for interrupt/exception attribute");
+
+	      /* Advance to next id.  */
+	      id_list = TREE_CHAIN (id_list);
+	    }
+	}
+      else if (reset)
+	{
+	  /* Deal with reset.  */
+	  tree id_list;
+	  tree id;
+	  tree nmi, warm;
+	  unsigned int lower_bound;
+	  unsigned int upper_bound;
+
+	  /* Prepare id_list and identify id value so that
+	     we can check if total number of vectors is valid.  */
+	  id_list = TREE_VALUE (reset);
+	  id = TREE_VALUE (id_list);
+
+	  /* The maximum numbers for user's interrupt is 64.  */
+	  lower_bound = 0;
+	  upper_bound = 64;
+
+	  /* 3. Check valid integer value for reset.  */
+	  if (TREE_CODE (id) != INTEGER_CST
+	      || TREE_INT_CST_LOW (id) < lower_bound
+	      || TREE_INT_CST_LOW (id) > upper_bound)
+	    error ("invalid id value for reset attribute");
+
+	  /* 4. Check valid function for nmi/warm.  */
+	  nmi  = lookup_attribute ("nmi", func_attrs);
+	  warm = lookup_attribute ("warm", func_attrs);
+
+	  if (nmi != NULL_TREE)
+	    {
+	      tree nmi_func_list;
+	      tree nmi_func;
+
+	      nmi_func_list = TREE_VALUE (nmi);
+	      nmi_func = TREE_VALUE (nmi_func_list);
+
+	      /* Issue error if it is not a valid nmi function.  */
+	      if (TREE_CODE (nmi_func) != IDENTIFIER_NODE)
+		error ("invalid nmi function for reset attribute");
+	    }
+
+	  if (warm != NULL_TREE)
+	    {
+	      tree warm_func_list;
+	      tree warm_func;
+
+	      warm_func_list = TREE_VALUE (warm);
+	      warm_func = TREE_VALUE (warm_func_list);
+
+	      /* Issue error if it is not a valid warm function.  */
+	      if (TREE_CODE (warm_func) != IDENTIFIER_NODE)
+		error ("invalid warm function for reset attribute");
+	    }
+	}
+      else
+	{
+	  /* No interrupt, exception, or reset attribute is set.  */
+	  return;
+	}
+    }
+}
+
+static bool
+nds32_option_pragma_parse (tree args ATTRIBUTE_UNUSED,
+			   tree pop_target ATTRIBUTE_UNUSED)
+{
+  /* Currently, we do not parse any pragma target by ourself,
+     so just simply return false.  */
+  return false;
+}
+
+static void
+nds32_option_override (void)
+{
+  /* After all the command options have been parsed,
+     we shall deal with some flags for changing compiler settings.  */
+
+  /* At first, we check if we have to strictly
+     set some flags based on ISA family.  */
+  if (TARGET_ISA_V2)
+    {
+      /* Under V2 ISA, we need to strictly disable TARGET_V3PUSH.  */
+      target_flags &= ~MASK_V3PUSH;
+    }
+  if (TARGET_ISA_V3)
+    {
+      /* Under V3 ISA, currently nothing should be strictly set.  */
+    }
+  if (TARGET_ISA_V3M)
+    {
+      /* Under V3M ISA, we need to strictly enable TARGET_REDUCED_REGS.  */
+      target_flags |= MASK_REDUCED_REGS;
+      /* Under V3M ISA, we need to strictly disable TARGET_PERF_EXT.  */
+      target_flags &= ~MASK_PERF_EXT;
+    }
+
+  /* See if we are using reduced-set registers:
+       $r0~$r5, $r6~$r10, $r15, $r28, $r29, $r30, $r31
+     If so, we must forbid using $r11~$r14, $r16~$r27.  */
+  if (TARGET_REDUCED_REGS)
+    {
+      int r;
+
+      /* Prevent register allocator from
+         choosing it as doing register allocation.  */
+      for (r = 11; r <= 14; r++)
+	fixed_regs[r] = call_used_regs[r] = 1;
+      for (r = 16; r <= 27; r++)
+	fixed_regs[r] = call_used_regs[r] = 1;
+    }
+
+  /* See if user explicitly would like to use fp-as-gp optimization.
+     If so, we must prevent $fp from being allocated
+     during register allocation.  */
+  if (TARGET_FORCE_FP_AS_GP)
+    fixed_regs[FP_REGNUM] = call_used_regs[FP_REGNUM] = 1;
+
+  if (!TARGET_16_BIT)
+    {
+      /* Under no 16 bit ISA, we need to strictly disable TARGET_V3PUSH.  */
+      target_flags &= ~MASK_V3PUSH;
+    }
+
+  /* Currently, we don't support PIC code generation yet.  */
+  if (flag_pic)
+    sorry ("not support -fpic");
+}
+
+
+/* Miscellaneous Parameters.  */
+
+static void
+nds32_init_builtins (void)
+{
+  tree pointer_type_node  = build_pointer_type (integer_type_node);
+
+  tree void_ftype_void    = build_function_type (void_type_node,
+						 void_list_node);
+
+  tree void_ftype_pint    = build_function_type_list (void_type_node,
+						      pointer_type_node,
+						      NULL_TREE);
+
+  tree int_ftype_int      = build_function_type_list (integer_type_node,
+						      integer_type_node,
+						      NULL_TREE);
+
+  tree void_ftype_int_int = build_function_type_list (void_type_node,
+						      integer_type_node,
+						      integer_type_node,
+						      NULL_TREE);
+
+  /* Cache.  */
+  add_builtin_function ("__builtin_nds32_isync",  void_ftype_pint,
+			NDS32_BUILTIN_ISYNC,
+			BUILT_IN_MD, NULL, NULL_TREE);
+  add_builtin_function ("__builtin_nds32_isb",  void_ftype_void,
+			NDS32_BUILTIN_ISB,
+			BUILT_IN_MD, NULL, NULL_TREE);
+
+  /* Register Transfer.  */
+  add_builtin_function ("__builtin_nds32_mfsr",  int_ftype_int,
+			NDS32_BUILTIN_MFSR,
+			BUILT_IN_MD, NULL, NULL_TREE);
+  add_builtin_function ("__builtin_nds32_mfusr", int_ftype_int,
+			NDS32_BUILTIN_MFUSR,
+			BUILT_IN_MD, NULL, NULL_TREE);
+  add_builtin_function ("__builtin_nds32_mtsr",  void_ftype_int_int,
+			NDS32_BUILTIN_MTSR,
+			BUILT_IN_MD, NULL, NULL_TREE);
+  add_builtin_function ("__builtin_nds32_mtusr", void_ftype_int_int,
+			NDS32_BUILTIN_MTUSR,
+			BUILT_IN_MD, NULL, NULL_TREE);
+
+  /* Interrupt.  */
+  add_builtin_function ("__builtin_nds32_setgie_en",  void_ftype_void,
+			NDS32_BUILTIN_SETGIE_EN,
+			BUILT_IN_MD, NULL, NULL_TREE);
+  add_builtin_function ("__builtin_nds32_setgie_dis", void_ftype_void,
+			NDS32_BUILTIN_SETGIE_DIS,
+			BUILT_IN_MD, NULL, NULL_TREE);
+}
+
+static rtx
+nds32_expand_builtin (tree exp,
+		      rtx target,
+		      rtx subtarget ATTRIBUTE_UNUSED,
+		      enum machine_mode mode ATTRIBUTE_UNUSED,
+		      int ignore ATTRIBUTE_UNUSED)
+{
+  tree fndecl = TREE_OPERAND (CALL_EXPR_FN (exp), 0);
+
+  int fcode = DECL_FUNCTION_CODE (fndecl);
+
+  switch (fcode)
+    {
+    /* Cache.  */
+    case NDS32_BUILTIN_ISYNC:
+      return nds32_expand_builtin_null_ftype_reg
+	     (CODE_FOR_unspec_volatile_isync, exp, target);
+    case NDS32_BUILTIN_ISB:
+      /* Since there are no result and operands for isb instruciton,
+         we can simply emit this rtx.  */
+      emit_insn (gen_unspec_volatile_isb ());
+      return target;
+
+    /* Register Transfer.  */
+    case NDS32_BUILTIN_MFSR:
+      return nds32_expand_builtin_reg_ftype_imm
+	     (CODE_FOR_unspec_volatile_mfsr, exp, target);
+    case NDS32_BUILTIN_MFUSR:
+      return nds32_expand_builtin_reg_ftype_imm
+	     (CODE_FOR_unspec_volatile_mfusr, exp, target);
+    case NDS32_BUILTIN_MTSR:
+      return nds32_expand_builtin_null_ftype_reg_imm
+	     (CODE_FOR_unspec_volatile_mtsr, exp, target);
+    case NDS32_BUILTIN_MTUSR:
+      return nds32_expand_builtin_null_ftype_reg_imm
+	     (CODE_FOR_unspec_volatile_mtusr, exp, target);
+
+    /* Interrupt.  */
+    case NDS32_BUILTIN_SETGIE_EN:
+      /* Since there are no result and operands for setgie.e instruciton,
+         we can simply emit this rtx.  */
+      emit_insn (gen_unspec_volatile_setgie_en ());
+      return target;
+    case NDS32_BUILTIN_SETGIE_DIS:
+      /* Since there are no result and operands for setgie.d instruciton,
+         we can simply emit this rtx.  */
+      emit_insn (gen_unspec_volatile_setgie_dis ());
+      return target;
+
+    default:
+      gcc_unreachable ();
+    }
+
+  return NULL_RTX;
+}
+
+
+/* ------------------------------------------------------------------------ */
+
+/* PART 4: Implemet extern function definitions,
+           the prototype is in nds32-protos.h.  */
+
+/* Defining Data Structures for Per-function Information.  */
+
+void
+nds32_init_expanders (void)
+{
+  /* Arrange to initialize and mark the machine per-function status.  */
+  init_machine_status = nds32_init_machine_status;
+}
+
+
+/* Register Usage.  */
+
+/* How Values Fit in Registers.  */
+
+int
+nds32_hard_regno_nregs (int regno ATTRIBUTE_UNUSED,
+			enum machine_mode mode)
+{
+  return ((GET_MODE_SIZE (mode) + UNITS_PER_WORD - 1) / UNITS_PER_WORD);
+}
+
+int
+nds32_hard_regno_mode_ok (int regno, enum machine_mode mode)
+{
+  /* Restrict double-word quantities to even register pairs.  */
+  if (HARD_REGNO_NREGS (regno, mode) == 1
+      || !((regno) & 1))
+    return 1;
+
+  return 0;
+}
+
+
+/* Register Classes.  */
+
+enum reg_class
+nds32_regno_reg_class (int regno)
+{
+  /* Refer to nds32.h for more register class details.  */
+
+  if (regno >= 0 && regno <= 7)
+    return LOW_REGS;
+  else if (regno >= 8 && regno <= 11)
+    return MIDDLE_REGS;
+  else if (regno >= 12 && regno <= 14)
+    return HIGH_REGS;
+  else if (regno == 15)
+    return R15_TA_REG;
+  else if (regno >= 16 && regno <= 19)
+    return MIDDLE_REGS;
+  else if (regno >= 20 && regno <= 31)
+    return HIGH_REGS;
+  else if (regno == 32 || regno == 33)
+    return FRAME_REGS;
+  else
+    return NO_REGS;
+}
+
+
+/* Stack Layout and Calling Conventions.  */
+
+/* Basic Stack Layout.  */
+
+rtx
+nds32_return_addr_rtx (int count,
+		       rtx frameaddr ATTRIBUTE_UNUSED)
+{
+  /* There is no way to determine the return address
+     if frameaddr is the frame that has 'count' steps
+     up from current frame.  */
+  if (count != 0)
+    return NULL_RTX;
+
+  /* If count == 0, it means we are at current frame,
+     the return address is $r30 ($lp).  */
+  return get_hard_reg_initial_val (Pmode, LP_REGNUM);
+}
+
+/* Eliminating Frame Pointer and Arg Pointer.  */
+
+HOST_WIDE_INT
+nds32_initial_elimination_offset (unsigned int from_reg, unsigned int to_reg)
+{
+  HOST_WIDE_INT offset;
+
+  /* Compute and setup stack frame size.
+     The result will be in cfun->machine.  */
+  nds32_compute_stack_frame ();
+
+  /* Remember to consider
+     cfun->machine->callee_saved_area_padding_bytes
+     when calculating offset.  */
+  if (from_reg == ARG_POINTER_REGNUM && to_reg == STACK_POINTER_REGNUM)
+    {
+      offset = (cfun->machine->fp_size
+	        + cfun->machine->gp_size
+		+ cfun->machine->lp_size
+		+ cfun->machine->callee_saved_regs_size
+		+ cfun->machine->callee_saved_area_padding_bytes
+		+ cfun->machine->local_size
+		+ cfun->machine->out_args_size);
+    }
+  else if (from_reg == ARG_POINTER_REGNUM
+	   && to_reg == HARD_FRAME_POINTER_REGNUM)
+    {
+      offset = 0;
+    }
+  else if (from_reg == FRAME_POINTER_REGNUM
+	   && to_reg == STACK_POINTER_REGNUM)
+    {
+      offset = (cfun->machine->local_size + cfun->machine->out_args_size);
+    }
+  else if (from_reg == FRAME_POINTER_REGNUM
+	   && to_reg == HARD_FRAME_POINTER_REGNUM)
+    {
+      offset = (-1) * (cfun->machine->fp_size
+		       + cfun->machine->gp_size
+		       + cfun->machine->lp_size
+		       + cfun->machine->callee_saved_regs_size
+		       + cfun->machine->callee_saved_area_padding_bytes);
+    }
+  else
+    {
+      gcc_unreachable ();
+    }
+
+  return offset;
+}
+
+/* Passing Arguments in Registers.  */
+
+void
+nds32_init_cumulative_args (CUMULATIVE_ARGS *cum,
+			    tree fntype ATTRIBUTE_UNUSED,
+			    rtx libname ATTRIBUTE_UNUSED,
+			    tree fndecl ATTRIBUTE_UNUSED,
+			    int n_named_args ATTRIBUTE_UNUSED)
+{
+  /* Initial available registers
+     (in offset, corresponding to NDS32_GPR_ARG_FIRST_REGNUM)
+     for passing arguments.  */
+  cum->reg_offset = 0;
+}
+
+/* Function Entry and Exit.  */
+
+/* Function for normal multiple push prologue.  */
+void
+nds32_expand_prologue (void)
+{
+  int fp_adjust;
+  int sp_adjust;
+  int en4_const;
+
+  rtx Rb, Re;
+  rtx push_insn;
+  rtx fp_adjust_insn, sp_adjust_insn;
+
+  /* Compute and setup stack frame size.
+     The result will be in cfun->machine.  */
+  nds32_compute_stack_frame ();
+
+  /* If the function is 'naked',
+     we do not have to generate prologue code fragment.  */
+  if (cfun->machine->naked_p)
+    return;
+
+  /* Get callee_first_regno and callee_last_regno.  */
+  Rb = gen_rtx_REG (SImode, cfun->machine->callee_saved_regs_first_regno);
+  Re = gen_rtx_REG (SImode, cfun->machine->callee_saved_regs_last_regno);
+
+  /* push_insn = gen_stack_push_multiple(first_regno, last_regno),
+     the pattern 'stack_push_multiple' is implemented in nds32.md.
+     For En4 field, we have to calculate its constant value.
+     Refer to Andes ISA for more information.  */
+  en4_const = 0;
+  if (cfun->machine->fp_size)
+    en4_const += 8;
+  if (cfun->machine->gp_size)
+    en4_const += 4;
+  if (cfun->machine->lp_size)
+    en4_const += 2;
+
+  /* If $fp, $gp, $lp, and all callee-save registers are NOT required
+     to be saved, we don't have to create multiple push instruction.
+     Otherwise, a multiple push instruction is needed.  */
+  if (!(REGNO (Rb) == SP_REGNUM && REGNO (Re) == SP_REGNUM && en4_const == 0))
+    {
+      /* Create multiple push instruction rtx.  */
+      push_insn = nds32_gen_stack_push_multiple (Rb, Re, GEN_INT (en4_const));
+      /* Emit rtx into instructions list and receive INSN rtx form.  */
+      push_insn = emit_insn (push_insn);
+
+      /* The insn rtx 'push_insn' will change frame layout.
+         We need to use RTX_FRAME_RELATED_P so that GCC is able to
+         generate CFI (Call Frame Information) stuff.  */
+      RTX_FRAME_RELATED_P (push_insn) = 1;
+    }
+
+  /* Check frame_pointer_needed to see
+     if we shall emit fp adjustment instruction.  */
+  if (frame_pointer_needed)
+    {
+      /* adjust $fp = $sp + ($fp size) + ($gp size) + ($lp size)
+                          + (4 * callee-saved-registers)
+         Note: No need to adjust
+               cfun->machine->callee_saved_area_padding_bytes,
+               because, at this point, stack pointer is just
+               at the position after push instruction.  */
+      fp_adjust = cfun->machine->fp_size
+		  + cfun->machine->gp_size
+		  + cfun->machine->lp_size
+		  + cfun->machine->callee_saved_regs_size;
+      fp_adjust_insn = gen_addsi3 (hard_frame_pointer_rtx,
+				   stack_pointer_rtx,
+				   GEN_INT (fp_adjust));
+      /* Emit rtx into instructions list and receive INSN rtx form.  */
+      fp_adjust_insn = emit_insn (fp_adjust_insn);
+    }
+
+  /* Adjust $sp = $sp - local_size - out_args_size
+                      - callee_saved_area_padding_bytes.  */
+  sp_adjust = cfun->machine->local_size
+	      + cfun->machine->out_args_size
+	      + cfun->machine->callee_saved_area_padding_bytes;
+  /* sp_adjust value may be out of range of the addi instruction,
+     create alternative add behavior with TA_REGNUM if necessary,
+     using NEGATIVE value to tell that we are decreasing address.  */
+  sp_adjust = nds32_force_addi_stack_int ( (-1) * sp_adjust);
+  if (sp_adjust)
+    {
+      /* Generate sp adjustment instruction if and only if sp_adjust != 0.  */
+      sp_adjust_insn = gen_addsi3 (stack_pointer_rtx,
+				   stack_pointer_rtx,
+				   GEN_INT (-1 * sp_adjust));
+      /* Emit rtx into instructions list and receive INSN rtx form.  */
+      sp_adjust_insn = emit_insn (sp_adjust_insn);
+
+      /* The insn rtx 'sp_adjust_insn' will change frame layout.
+         We need to use RTX_FRAME_RELATED_P so that GCC is able to
+         generate CFI (Call Frame Information) stuff.  */
+      RTX_FRAME_RELATED_P (sp_adjust_insn) = 1;
+    }
+
+  /* Prevent the instruction scheduler from
+     moving instructions across the boundary.  */
+  emit_insn (gen_blockage ());
+}
+
+/* Function for normal multiple pop epilogue.  */
+void
+nds32_expand_epilogue (void)
+{
+  int sp_adjust;
+  int en4_const;
+
+  rtx Rb, Re;
+  rtx pop_insn;
+  rtx sp_adjust_insn;
+
+  /* Compute and setup stack frame size.
+     The result will be in cfun->machine.  */
+  nds32_compute_stack_frame ();
+
+  /* Prevent the instruction scheduler from
+     moving instructions across the boundary.  */
+  emit_insn (gen_blockage ());
+
+  /* If the function is 'naked', we do not have to generate
+     epilogue code fragment BUT 'ret' instruction.  */
+  if (cfun->machine->naked_p)
+    {
+      /* Generate return instruction by using unspec_func_return pattern.
+         Make sure this instruction is after gen_blockage().
+         NOTE that $lp will become 'live'
+         after this instruction has been emitted.  */
+      emit_insn (gen_unspec_func_return ());
+      return;
+    }
+
+  if (frame_pointer_needed)
+    {
+      /* adjust $sp = $fp - ($fp size) - ($gp size) - ($lp size)
+                          - (4 * callee-saved-registers)
+         Note: No need to adjust
+               cfun->machine->callee_saved_area_padding_bytes,
+               because we want to adjust stack pointer
+               to the position for pop instruction.  */
+      sp_adjust = cfun->machine->fp_size
+		  + cfun->machine->gp_size
+		  + cfun->machine->lp_size
+		  + cfun->machine->callee_saved_regs_size;
+      sp_adjust_insn = gen_addsi3 (stack_pointer_rtx,
+				   hard_frame_pointer_rtx,
+				   GEN_INT (-1 * sp_adjust));
+      /* Emit rtx into instructions list and receive INSN rtx form.  */
+      sp_adjust_insn = emit_insn (sp_adjust_insn);
+    }
+  else
+    {
+      /* If frame pointer is NOT needed,
+         we cannot calculate the sp adjustment from frame pointer.
+         Instead, we calculate the adjustment by local_size,
+         out_args_size, and callee_saved_area_padding_bytes.
+         Notice that such sp adjustment value may be out of range,
+         so we have to deal with it as well.  */
+
+      /* Adjust $sp = $sp + local_size + out_args_size
+                          + callee_saved_area_padding_bytes.  */
+      sp_adjust = cfun->machine->local_size
+		  + cfun->machine->out_args_size
+		  + cfun->machine->callee_saved_area_padding_bytes;
+      /* sp_adjust value may be out of range of the addi instruction,
+         create alternative add behavior with TA_REGNUM if necessary,
+         using POSITIVE value to tell that we are increasing address.  */
+      sp_adjust = nds32_force_addi_stack_int (sp_adjust);
+      if (sp_adjust)
+	{
+	  /* Generate sp adjustment instruction
+	     if and only if sp_adjust != 0.  */
+	  sp_adjust_insn = gen_addsi3 (stack_pointer_rtx,
+				       stack_pointer_rtx,
+				       GEN_INT (sp_adjust));
+	  /* Emit rtx into instructions list and receive INSN rtx form.  */
+	  sp_adjust_insn = emit_insn (sp_adjust_insn);
+	}
+    }
+
+  /* Get callee_first_regno and callee_last_regno.  */
+  Rb = gen_rtx_REG (SImode, cfun->machine->callee_saved_regs_first_regno);
+  Re = gen_rtx_REG (SImode, cfun->machine->callee_saved_regs_last_regno);
+
+  /* pop_insn = gen_stack_pop_multiple(first_regno, last_regno),
+     the pattern 'stack_pop_multiple' is implementad in nds32.md.
+     For En4 field, we have to calculate its constant value.
+     Refer to Andes ISA for more information.  */
+  en4_const = 0;
+  if (cfun->machine->fp_size)
+    en4_const += 8;
+  if (cfun->machine->gp_size)
+    en4_const += 4;
+  if (cfun->machine->lp_size)
+    en4_const += 2;
+
+  /* If fp$, $gp, $lp, and all callee-save registers are NOT required
+     to be saved, we don't have to create multiple pop instruction.
+     Otherwise, a multiple pop instruction is needed.  */
+  if (!(REGNO (Rb) == SP_REGNUM && REGNO (Re) == SP_REGNUM && en4_const == 0))
+    {
+      /* Create multiple push instruction rtx.  */
+      pop_insn = nds32_gen_stack_pop_multiple (Rb, Re, GEN_INT (en4_const));
+      /* Emit pop instruction.  */
+      emit_insn (pop_insn);
+    }
+
+  /* Generate return instruction by using unspec_func_return pattern.  */
+  emit_insn (gen_unspec_func_return ());
+}
+
+/* Function for v3push prologue.  */
+void
+nds32_expand_prologue_v3push (void)
+{
+  int fp_adjust;
+  int sp_adjust;
+
+  rtx Rb, Re;
+  rtx push_insn;
+  rtx fp_adjust_insn, sp_adjust_insn;
+
+  /* Compute and setup stack frame size.
+     The result will be in cfun->machine.  */
+  nds32_compute_stack_frame ();
+
+  /* If the function is 'naked',
+     we do not have to generate prologue code fragment.  */
+  if (cfun->machine->naked_p)
+    return;
+
+  /* Get callee_first_regno and callee_last_regno.  */
+  Rb = gen_rtx_REG (SImode, cfun->machine->callee_saved_regs_first_regno);
+  Re = gen_rtx_REG (SImode, cfun->machine->callee_saved_regs_last_regno);
+
+  /* Calculate sp_adjust first to test if 'v3push Re,imm8u' is available,
+     where imm8u has to be 8-byte alignment.  */
+  sp_adjust = cfun->machine->local_size
+	      + cfun->machine->out_args_size
+	      + cfun->machine->callee_saved_area_padding_bytes;
+
+  if (satisfies_constraint_Iu08 (GEN_INT (sp_adjust))
+      && NDS32_DOUBLE_WORD_ALIGN_P (sp_adjust))
+    {
+      /* We can use 'v3push Re,imm8u'.  */
+
+      /* push_insn = gen_stack_v3push(last_regno, sp_adjust),
+         the pattern 'stack_v3push' is implemented in nds32.md.
+         The (const_int 14) means v3push always push { $fp $gp $lp }.  */
+      push_insn = nds32_gen_stack_v3push (Rb, Re,
+					  GEN_INT (14), GEN_INT (sp_adjust));
+      /* emit rtx into instructions list and receive INSN rtx form */
+      push_insn = emit_insn (push_insn);
+
+      /* The insn rtx 'push_insn' will change frame layout.
+         We need to use RTX_FRAME_RELATED_P so that GCC is able to
+         generate CFI (Call Frame Information) stuff.  */
+      RTX_FRAME_RELATED_P (push_insn) = 1;
+
+      /* Check frame_pointer_needed to see
+         if we shall emit fp adjustment instruction.  */
+      if (frame_pointer_needed)
+	{
+	  /* adjust $fp = $sp   + 4         ($fp size)
+	                        + 4         ($gp size)
+	                        + 4         ($lp size)
+	                        + (4 * n)   (callee-saved registers)
+	                        + sp_adjust ('v3push Re,imm8u')
+	     Note: Since we use 'v3push Re,imm8u',
+	           the position of stack pointer is further
+	           changed after push instruction.
+	           Hence, we need to take sp_adjust value
+	           into consideration.  */
+	  fp_adjust = cfun->machine->fp_size
+		      + cfun->machine->gp_size
+		      + cfun->machine->lp_size
+		      + cfun->machine->callee_saved_regs_size
+		      + sp_adjust;
+	  fp_adjust_insn = gen_addsi3 (hard_frame_pointer_rtx,
+				       stack_pointer_rtx,
+				       GEN_INT (fp_adjust));
+	  /* Emit rtx into instructions list and receive INSN rtx form.  */
+	  fp_adjust_insn = emit_insn (fp_adjust_insn);
+	}
+    }
+  else
+    {
+      /* We have to use 'v3push Re,0' and
+         expand one more instruction to adjust $sp later.  */
+
+      /* push_insn = gen_stack_v3push(last_regno, sp_adjust),
+         the pattern 'stack_v3push' is implemented in nds32.md.
+         The (const_int 14) means v3push always push { $fp $gp $lp }.  */
+      push_insn = nds32_gen_stack_v3push (Rb, Re,
+					  GEN_INT (14), GEN_INT (0));
+      /* Emit rtx into instructions list and receive INSN rtx form.  */
+      push_insn = emit_insn (push_insn);
+
+      /* The insn rtx 'push_insn' will change frame layout.
+         We need to use RTX_FRAME_RELATED_P so that GCC is able to
+         generate CFI (Call Frame Information) stuff.  */
+      RTX_FRAME_RELATED_P (push_insn) = 1;
+
+      /* Check frame_pointer_needed to see
+         if we shall emit fp adjustment instruction.  */
+      if (frame_pointer_needed)
+	{
+	  /* adjust $fp = $sp + 4        ($fp size)
+	                      + 4        ($gp size)
+	                      + 4        ($lp size)
+	                      + (4 * n)  (callee-saved registers)
+	     Note: Since we use 'v3push Re,0',
+	           the stack pointer is just at the position
+	           after push instruction.
+	           No need to take sp_adjust into consideration.  */
+	  fp_adjust = cfun->machine->fp_size
+		      + cfun->machine->gp_size
+		      + cfun->machine->lp_size
+		      + cfun->machine->callee_saved_regs_size;
+	  fp_adjust_insn = gen_addsi3 (hard_frame_pointer_rtx,
+				       stack_pointer_rtx,
+				       GEN_INT (fp_adjust));
+	  /* Emit rtx into instructions list and receive INSN rtx form.  */
+	  fp_adjust_insn = emit_insn (fp_adjust_insn);
+	}
+
+      /* Because we use 'v3push Re,0',
+         we need to expand one more instruction to adjust $sp.
+         However, sp_adjust value may be out of range of the addi instruction,
+         create alternative add behavior with TA_REGNUM if necessary,
+         using NEGATIVE value to tell that we are decreasing address.  */
+      sp_adjust = nds32_force_addi_stack_int ( (-1) * sp_adjust);
+      if (sp_adjust)
+	{
+	  /* Generate sp adjustment instruction
+	     if and only if sp_adjust != 0.  */
+	  sp_adjust_insn = gen_addsi3 (stack_pointer_rtx,
+				       stack_pointer_rtx,
+				       GEN_INT (-1 * sp_adjust));
+	  /* Emit rtx into instructions list and receive INSN rtx form.  */
+	  sp_adjust_insn = emit_insn (sp_adjust_insn);
+
+	  /* The insn rtx 'sp_adjust_insn' will change frame layout.
+	     We need to use RTX_FRAME_RELATED_P so that GCC is able to
+	     generate CFI (Call Frame Information) stuff.  */
+	  RTX_FRAME_RELATED_P (sp_adjust_insn) = 1;
+	}
+    }
+
+  /* Prevent the instruction scheduler from
+     moving instructions across the boundary.  */
+  emit_insn (gen_blockage ());
+}
+
+/* Function for v3pop epilogue.  */
+void
+nds32_expand_epilogue_v3pop (void)
+{
+  int sp_adjust;
+
+  rtx Rb, Re;
+  rtx pop_insn;
+  rtx sp_adjust_insn;
+
+  /* Compute and setup stack frame size.
+     The result will be in cfun->machine.  */
+  nds32_compute_stack_frame ();
+
+  /* Prevent the instruction scheduler from
+     moving instructions across the boundary.  */
+  emit_insn (gen_blockage ());
+
+  /* If the function is 'naked', we do not have to generate
+     epilogue code fragment BUT 'ret' instruction.  */
+  if (cfun->machine->naked_p)
+    {
+      /* Generate return instruction by using unspec_func_return pattern.
+         Make sure this instruction is after gen_blockage().
+         NOTE that $lp will become 'live'
+         after this instruction has been emitted.  */
+      emit_insn (gen_unspec_func_return ());
+      return;
+    }
+
+  /* Get callee_first_regno and callee_last_regno.  */
+  Rb = gen_rtx_REG (SImode, cfun->machine->callee_saved_regs_first_regno);
+  Re = gen_rtx_REG (SImode, cfun->machine->callee_saved_regs_last_regno);
+
+  /* Calculate sp_adjust first to test if 'v3pop Re,imm8u' is available,
+     where imm8u has to be 8-byte alignment.  */
+  sp_adjust = cfun->machine->local_size
+	      + cfun->machine->out_args_size
+	      + cfun->machine->callee_saved_area_padding_bytes;
+
+  /* We have to consider alloca issue as well.
+     If the function does call alloca(), the stack pointer is not fixed.
+     In that case, we cannot use 'v3pop Re,imm8u' directly.
+     We have to caculate stack pointer from frame pointer
+     and then use 'v3pop Re,0'.
+     Of course, the frame_pointer_needed should be nonzero
+     if the function calls alloca().  */
+  if (satisfies_constraint_Iu08 (GEN_INT (sp_adjust))
+      && NDS32_DOUBLE_WORD_ALIGN_P (sp_adjust)
+      && !cfun->calls_alloca)
+    {
+      /* We can use 'v3pop Re,imm8u'.  */
+
+      /* pop_insn = gen_stack_v3pop(last_regno, sp_adjust),
+         the pattern 'stack_v3pop' is implementad in nds32.md.
+         The (const_int 14) means v3pop always push { $fp $gp $lp }.  */
+      pop_insn = nds32_gen_stack_v3pop (Rb, Re,
+					GEN_INT (14), GEN_INT (sp_adjust));
+
+      /* Emit pop instruction.  */
+      emit_insn (pop_insn);
+    }
+  else
+    {
+      /* We have to use 'v3pop Re,0', and prior to it,
+         we must expand one more instruction to adjust $sp.  */
+
+      if (frame_pointer_needed)
+	{
+	  /* adjust $sp = $fp - 4        ($fp size)
+	                      - 4        ($gp size)
+	                      - 4        ($lp size)
+	                      - (4 * n)  (callee-saved registers)
+	     Note: No need to adjust
+	           cfun->machine->callee_saved_area_padding_bytes,
+	           because we want to adjust stack pointer
+	           to the position for pop instruction.  */
+	  sp_adjust = cfun->machine->fp_size
+		      + cfun->machine->gp_size
+		      + cfun->machine->lp_size
+		      + cfun->machine->callee_saved_regs_size;
+	  sp_adjust_insn = gen_addsi3 (stack_pointer_rtx,
+				       hard_frame_pointer_rtx,
+				       GEN_INT (-1 * sp_adjust));
+	  /* Emit rtx into instructions list and receive INSN rtx form.  */
+	  sp_adjust_insn = emit_insn (sp_adjust_insn);
+	}
+      else
+	{
+	  /* If frame pointer is NOT needed,
+	     we cannot calculate the sp adjustment from frame pointer.
+	     Instead, we calculate the adjustment by local_size,
+	     out_args_size, and callee_saved_area_padding_bytes.
+	     Notice that such sp adjustment value may be out of range,
+	     so we have to deal with it as well.  */
+
+	  /* Adjust $sp = $sp + local_size + out_args_size
+			      + callee_saved_area_padding_bytes.  */
+	  sp_adjust = cfun->machine->local_size
+		      + cfun->machine->out_args_size
+		      + cfun->machine->callee_saved_area_padding_bytes;
+	  /* sp_adjust value may be out of range of the addi instruction,
+	     create alternative add behavior with TA_REGNUM if necessary,
+	     using POSITIVE value to tell that we are increasing address.  */
+	  sp_adjust = nds32_force_addi_stack_int (sp_adjust);
+	  if (sp_adjust)
+	    {
+	      /* Generate sp adjustment instruction
+	         if and only if sp_adjust != 0.  */
+	      sp_adjust_insn = gen_addsi3 (stack_pointer_rtx,
+					   stack_pointer_rtx,
+					   GEN_INT (sp_adjust));
+	      /* Emit rtx into instructions list and receive INSN rtx form.  */
+	      sp_adjust_insn = emit_insn (sp_adjust_insn);
+	    }
+	}
+
+      /* pop_insn = gen_stack_v3pop(last_regno, sp_adjust),
+         the pattern 'stack_v3pop' is implementad in nds32.md.  */
+      /* The (const_int 14) means v3pop always push { $fp $gp $lp }.  */
+      pop_insn = nds32_gen_stack_v3pop (Rb, Re,
+					GEN_INT (14), GEN_INT (0));
+
+      /* Emit pop instruction.  */
+      emit_insn (pop_insn);
+    }
+}
+
+/* ------------------------------------------------------------------------ */
+
+/* Function to test 333-form for load/store instructions.
+   This is auxiliary extern function for auxiliary macro in nds32.h.
+   Because it is a little complicated, we use function instead of macro.  */
+bool
+nds32_ls_333_p (rtx rt, rtx ra, rtx imm, enum machine_mode mode)
+{
+  if (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS
+      && REGNO_REG_CLASS (REGNO (ra)) == LOW_REGS)
+    {
+      if (GET_MODE_SIZE (mode) == 4)
+	return satisfies_constraint_Iu05 (imm);
+
+      if (GET_MODE_SIZE (mode) == 2)
+	return satisfies_constraint_Iu04 (imm);
+
+      if (GET_MODE_SIZE (mode) == 1)
+	return satisfies_constraint_Iu03 (imm);
+    }
+
+  return false;
+}
+
+
+/* Functions to expand load_multiple and store_multiple.
+   They are auxiliary extern functions to help create rtx template.
+   Check nds32-multiple.md file for the patterns.  */
+rtx
+nds32_expand_load_multiple (int base_regno, int count,
+			    rtx base_addr, rtx basemem)
+{
+  int par_index;
+  int offset;
+  rtx result;
+  rtx new_addr, mem, reg;
+
+  /* Create the pattern that is presented in nds32-multiple.md.  */
+
+  result = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (count));
+
+  for (par_index = 0; par_index < count; par_index++)
+    {
+      offset   = par_index * 4;
+      /* 4-byte for loading data to each register.  */
+      new_addr = plus_constant (Pmode, base_addr, offset);
+      mem      = adjust_automodify_address_nv (basemem, SImode,
+					       new_addr, offset);
+      reg      = gen_rtx_REG (SImode, base_regno + par_index);
+
+      XVECEXP (result, 0, par_index) = gen_rtx_SET (VOIDmode, reg, mem);
+    }
+
+  return result;
+}
+
+rtx
+nds32_expand_store_multiple (int base_regno, int count,
+			     rtx base_addr, rtx basemem)
+{
+  int par_index;
+  int offset;
+  rtx result;
+  rtx new_addr, mem, reg;
+
+  /* Create the pattern that is presented in nds32-multiple.md.  */
+
+  result = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (count));
+
+  for (par_index = 0; par_index < count; par_index++)
+    {
+      offset   = par_index * 4;
+      /* 4-byte for storing data to memory.  */
+      new_addr = plus_constant (Pmode, base_addr, offset);
+      mem      = adjust_automodify_address_nv (basemem, SImode,
+					       new_addr, offset);
+      reg      = gen_rtx_REG (SImode, base_regno + par_index);
+
+      XVECEXP (result, 0, par_index) = gen_rtx_SET (VOIDmode, mem, reg);
+    }
+
+  return result;
+}
+
+/* Function to move block memory content by
+   using load_multiple and store_multiple.
+   This is auxiliary extern function to help create rtx template.
+   Check nds32-multiple.md file for the patterns.  */
+int
+nds32_expand_movmemqi (rtx dstmem, rtx srcmem, rtx total_bytes, rtx alignment)
+{
+  HOST_WIDE_INT in_words, out_words;
+  rtx dst_base_reg, src_base_reg;
+  int maximum_bytes;
+
+  /* Because reduced-set regsiters has few registers
+     (r0~r5, r6~10, r15, r28~r31, where 'r15' and 'r28~r31'
+      cannot be used for register allocation),
+     using 8 registers (32 bytes) for moving memory block
+     may easily consume all of them.
+     It makes register allocation/spilling hard to work.
+     So we only allow maximum=4 registers (16 bytes) for
+     moving memory block under reduced-set registers.  */
+  if (TARGET_REDUCED_REGS)
+    maximum_bytes = 16;
+  else
+    maximum_bytes = 32;
+
+  /* 1. Total_bytes is integer for sure.
+     2. Alignment is integer for sure.
+     3. Maximum 4 or 8 registers, 4 * 4 = 16 bytes, 8 * 4 = 32 bytes.
+     4. Requires (n * 4) block size.
+     5. Requires 4-byte alignment.  */
+  if (GET_CODE (total_bytes) != CONST_INT
+      || GET_CODE (alignment) != CONST_INT
+      || INTVAL (total_bytes) > maximum_bytes
+      || INTVAL (total_bytes) & 3
+      || INTVAL (alignment) & 3)
+    return 0;
+
+  dst_base_reg = copy_to_mode_reg (SImode, XEXP (dstmem, 0));
+  src_base_reg = copy_to_mode_reg (SImode, XEXP (srcmem, 0));
+
+  out_words = in_words = INTVAL (total_bytes) / UNITS_PER_WORD;
+
+  emit_insn (nds32_expand_load_multiple (0, in_words, src_base_reg, srcmem));
+  emit_insn (nds32_expand_store_multiple (0, out_words, dst_base_reg, dstmem));
+
+  /* Successfully create patterns, return 1.  */
+  return 1;
+}
+
+/* Function to check whether the OP is a valid load/store operation.
+   This is a helper function for the predicates:
+   'nds32_load_multiple_operation' and 'nds32_store_multiple_operation'
+   in predicates.md file.
+
+   The OP is supposed to be a parallel rtx.
+   For each element within this parallel rtx:
+     (set (reg) (mem addr)) is the form for load operation.
+     (set (mem addr) (reg)) is the form for store operation.
+   We have to extract reg and mem of every element and
+   check if the information is valid for multiple load/store operation.  */
+bool
+nds32_valid_multiple_load_store (rtx op, bool load_p)
+{
+  HOST_WIDE_INT count;
+  int first_elt_regno;
+  rtx elt_reg;
+  rtx elt_mem;
+  int i;
+  rtx elt;
+
+  /* Get the counts of elements in the parallel rtx.  */
+  count = XVECLEN (op, 0);
+  /* Pick up the first element.  */
+  elt = XVECEXP (op, 0, 0);
+
+  /* Perform some quick check for the first element in the parallel rtx.  */
+  if (GET_CODE (elt) != SET
+      || count <= 1
+      || count > 8)
+    return false;
+
+  /* Pick up regno of first element for further detail checking.
+     Note that the form is different between load and store operation.  */
+  if (load_p)
+    {
+      if (GET_CODE (SET_DEST (elt)) != REG
+	  || GET_CODE (SET_SRC (elt)) != MEM)
+	return false;
+
+      first_elt_regno = REGNO (SET_DEST (elt));
+    }
+  else
+    {
+      if (GET_CODE (SET_SRC (elt)) != REG
+	  || GET_CODE (SET_DEST (elt)) != MEM)
+	return false;
+
+      first_elt_regno = REGNO (SET_SRC (elt));
+    }
+
+  /* Perform detail check for each element.
+     Refer to nds32-multiple.md for more information
+     about following checking.  */
+  for (i = 0; i < count; i++)
+    {
+      elt = XVECEXP (op, 0, i);
+
+      /* If this element is not a 'set' rtx, return false immediately.  */
+      if (GET_CODE (elt) != SET)
+	return false;
+
+      /* Pick up reg and mem of this element.  */
+      elt_reg = load_p ? SET_DEST (elt) : SET_SRC (elt);
+      elt_mem = load_p ? SET_SRC (elt) : SET_DEST (elt);
+
+      /* If elt_reg is not a expected reg rtx, return false.  */
+      if (GET_CODE (elt_reg) != REG || GET_MODE (elt_reg) != SImode)
+	return false;
+      /* If elt_mem is not a expected mem rtx, return false.  */
+      if (GET_CODE (elt_mem) != MEM || GET_MODE (elt_mem) != SImode)
+	return false;
+
+      /* If the register number is not continuous, return false.  */
+      if (REGNO (elt_reg) != (unsigned int) (first_elt_regno + i))
+	return false;
+      /* If the address of mem rtx is a not register or plus operation,
+         we should return false as well.  */
+      if (GET_CODE (XEXP (elt_mem, 0)) != REG
+	  && GET_CODE (XEXP (elt_mem, 0)) != PLUS)
+	return false;
+    }
+
+  return true;
+}
+
+
+/* Computing the Length of an Insn.
+   Modifies the length assigned to instruction INSN.
+   LEN is the initially computed length of the insn.  */
+int
+nds32_adjust_insn_length (rtx insn, int length)
+{
+  rtx src, dst;
+
+  switch (recog_memoized (insn))
+    {
+    case CODE_FOR_move_df:
+    case CODE_FOR_move_di:
+      /* Adjust length of movd44 to 2.  */
+      src = XEXP (PATTERN (insn), 1);
+      dst = XEXP (PATTERN (insn), 0);
+
+      if (REG_P (src)
+	  && REG_P (dst)
+	  && (REGNO (src) % 2) == 0
+	  && (REGNO (dst) % 2) == 0)
+	length = 2;
+      break;
+
+    default:
+      break;
+    }
+
+  return length;
+}
+
+
+/* Function to check if 'bclr' instruction can be used with IVAL.  */
+int
+nds32_can_use_bclr_p (int ival)
+{
+  int one_bit_count;
+
+  /* Calculate the number of 1-bit of (~ival), if there is only one 1-bit,
+     it means the original ival has only one 0-bit,
+     So it is ok to perform 'bclr' operation.  */
+
+  one_bit_count = popcount_hwi ((unsigned HOST_WIDE_INT) (~ival));
+
+  /* 'bclr' is a performance extension instruction.  */
+  return (TARGET_PERF_EXT && (one_bit_count == 1));
+}
+
+/* Function to check if 'bset' instruction can be used with IVAL.  */
+int
+nds32_can_use_bset_p (int ival)
+{
+  int one_bit_count;
+
+  /* Caculate the number of 1-bit of ival, if there is only one 1-bit,
+     it is ok to perform 'bset' operation.  */
+
+  one_bit_count = popcount_hwi ((unsigned HOST_WIDE_INT) (ival));
+
+  /* 'bset' is a performance extension instruction.  */
+  return (TARGET_PERF_EXT && (one_bit_count == 1));
+}
+
+/* Function to check if 'btgl' instruction can be used with IVAL.  */
+int
+nds32_can_use_btgl_p (int ival)
+{
+  int one_bit_count;
+
+  /* Caculate the number of 1-bit of ival, if there is only one 1-bit,
+     it is ok to perform 'btgl' operation.  */
+
+  one_bit_count = popcount_hwi ((unsigned HOST_WIDE_INT) (ival));
+
+  /* 'btgl' is a performance extension instruction.  */
+  return (TARGET_PERF_EXT && (one_bit_count == 1));
+}
+
+/* Function to check if 'bitci' instruction can be used with IVAL.  */
+int
+nds32_can_use_bitci_p (int ival)
+{
+  /* If we are using V3 ISA, we have 'bitci' instruction.
+     Try to see if we can present 'andi' semantic with
+     such 'bit-clear-immediate' operation.
+     For example, 'andi $r0,$r0,0xfffffffc' can be
+     presented with 'bitci $r0,$r0,3'.  */
+  return (TARGET_ISA_V3
+	  && (ival < 0)
+	  && satisfies_constraint_Iu15 (gen_int_mode (~ival, SImode)));
+}
+
+
+/* Return true if is load/store with SYMBOL_REF addressing mode
+   and memory mode is SImode.  */
+bool
+nds32_symbol_load_store_p (rtx insn)
+{
+  rtx mem_src = NULL_RTX;
+
+  switch (get_attr_type (insn))
+    {
+    case TYPE_LOAD:
+      mem_src = SET_SRC (PATTERN (insn));
+      break;
+    case TYPE_STORE:
+      mem_src = SET_DEST (PATTERN (insn));
+      break;
+    default:
+      break;
+    }
+
+  /* Find load/store insn with addressing mode is SYMBOL_REF.  */
+  if (mem_src != NULL_RTX)
+    {
+      if ((GET_CODE (mem_src) == ZERO_EXTEND)
+	  || (GET_CODE (mem_src) == SIGN_EXTEND))
+	mem_src = XEXP (mem_src, 0);
+
+      if ((GET_CODE (XEXP (mem_src, 0)) == SYMBOL_REF)
+	   || (GET_CODE (XEXP (mem_src, 0)) == LO_SUM))
+	return true;
+    }
+
+  return false;
+}
+
+/* Function to determine whether it is worth to do fp_as_gp optimization.
+   Return 0: It is NOT worth to do fp_as_gp optimization.
+   Return 1: It is APPROXIMATELY worth to do fp_as_gp optimization.
+   Note that if it is worth to do fp_as_gp optimization,
+   we MUST set FP_REGNUM ever live in this function.  */
+int
+nds32_fp_as_gp_check_available (void)
+{
+  /* If the register allocation and reload phase
+     have not completed yet, return 0 immediately.
+     We must check this at beginning, otherwise
+     the subsequent checking may cause segmentation fault.  */
+  if (!reload_completed)
+    return 0;
+
+  /* If cfun->machine->fp_as_gp_p is 1,
+     it means we have evaluted it previously
+     and decided to use fp_ap_gp optimization.
+     So there is no need to evalute it again.
+     Return 1 immediately.  */
+  if (cfun->machine->fp_as_gp_p)
+    return 1;
+
+  /* If there exists ANY of following conditions,
+     we DO NOT perform fp_as_gp optimization:
+       1. TARGET_FORBID_FP_AS_GP is set
+          regardless of the TARGET_FORCE_FP_AS_GP.
+       2. User explicitly uses 'naked' attribute.
+       3. Not optimize for size.
+       4. Need frame pointer.
+       5. If $fp is already required to be saved,
+          it means $fp is already choosen by register allocator.
+          Thus we better not to use it for fp_as_gp optimization.
+       6. This function is a vararg function.
+          DO NOT apply fp_as_gp optimization on this function
+          because it may change and break stack frame.
+       7. The epilogue is empty.
+          This happens when the function uses exit()
+          or its attribute is no_return.
+          In that case, compiler will not expand epilogue
+          so that we have no chance to output .omit_fp_end directive.  */
+  if (TARGET_FORBID_FP_AS_GP
+      || lookup_attribute ("naked", DECL_ATTRIBUTES (current_function_decl))
+      || !optimize_size
+      || frame_pointer_needed
+      || NDS32_REQUIRED_CALLEE_SAVED_P (FP_REGNUM)
+      || (cfun->stdarg == 1)
+      || (find_fallthru_edge (EXIT_BLOCK_PTR->preds) == NULL))
+    return 0;
+
+  /* Now we can check the possibility of using fp_as_gp optimization.  */
+  if (TARGET_FORCE_FP_AS_GP)
+    {
+      /* User explicitly issues -mforce-fp-as-gp option.  */
+      df_set_regs_ever_live (FP_REGNUM, 1);
+      return 1;
+    }
+  else
+    {
+      /* In the following we are going to evaluate whether
+         it is worth to do fp_as_gp optimization.  */
+      int good_gain     = 0;
+      int symbol_count  = 0;
+
+      int threshold;
+      rtx insn;
+
+      /* We check if there already requires prologue.
+         Note that $gp will be saved in prologue for PIC code generation.
+         After that, we can set threshold by the existence of prologue.
+         Each fp-implied instruction will gain 2-byte code size
+         from gp-aware instruction, so we have following heuristics.  */
+      if (flag_pic
+	  || nds32_have_prologue_p ())
+	{
+	  /* Have-prologue:
+	       Compiler already intends to generate prologue content,
+	       so the fp_as_gp optimization will only insert
+	       'la $fp,_FP_BASE_' instruction, which will be
+	       converted into 4-byte instruction at link time.
+	       The threshold is "3" symbol accesses, 2 + 2 + 2 > 4.  */
+	  threshold = 3;
+	}
+      else
+	{
+	  /* None-prologue:
+	       Compiler originally does not generate prologue content,
+	       so the fp_as_gp optimization will NOT ONLY insert
+	       'la $fp,_FP_BASE' instruction, but also causes
+	       push/pop instructions.
+	       If we are using v3push (push25/pop25),
+	       the threshold is "5" symbol accesses, 5*2 > 4 + 2 + 2;
+	       If we are using normal push (smw/lmw),
+	       the threshold is "5+2" symbol accesses 7*2 > 4 + 4 + 4.  */
+	  threshold = 5 + (TARGET_V3PUSH ? 0 : 2);
+	}
+
+      /* We would like to traverse every instruction in this function.
+         So we need to have push_topmost_sequence()/pop_topmost_sequence()
+         surrounding our for-loop evaluation.  */
+      push_topmost_sequence ();
+      /* Counting the insn number which the addressing mode is symbol.  */
+      for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+	{
+	  if (single_set (insn) && nds32_symbol_load_store_p (insn))
+	    symbol_count++;
+
+	  if (symbol_count == threshold)
+	    {
+	      good_gain = 1;
+	      break;
+	    }
+	}
+      pop_topmost_sequence ();
+
+      /* Enable fp_as_gp optimization when potential gain is good enough.  */
+      if (good_gain)
+	{
+	  df_set_regs_ever_live (FP_REGNUM, 1);
+	  return 1;
+	}
+    }
+
+  /* By default we return 0.  */
+  return 0;
+}
+
+
+/* Function to generate PC relative jump table.
+   Refer to nds32.md for more details.
+
+   The following is the sample for the case that diff value
+   can be presented in '.short' size.
+
+     addi    $r1, $r1, -(case_lower_bound)
+     slti    $ta, $r1, (case_number)
+     beqz    $ta, .L_skip_label
+
+     la      $ta, .L35             ! get jump table address
+     lh      $r1, [$ta + $r1 << 1] ! load symbol diff from jump table entry
+     addi    $ta, $r1, $ta
+     jr5     $ta
+
+     ! jump table entry
+   L35:
+     .short  .L25-.L35
+     .short  .L26-.L35
+     .short  .L27-.L35
+     .short  .L28-.L35
+     .short  .L29-.L35
+     .short  .L30-.L35
+     .short  .L31-.L35
+     .short  .L32-.L35
+     .short  .L33-.L35
+     .short  .L34-.L35 */
+const char *
+nds32_output_casesi_pc_relative (rtx *operands)
+{
+  enum machine_mode mode;
+  rtx diff_vec;
+
+  diff_vec = PATTERN (next_active_insn (operands[1]));
+
+  gcc_assert (GET_CODE (diff_vec) == ADDR_DIFF_VEC);
+
+  /* Step C: "t <-- operands[1]".  */
+  output_asm_insn ("la\t$ta, %l1", operands);
+
+  /* Get the mode of each element in the difference vector.  */
+  mode = GET_MODE (diff_vec);
+
+  /* Step D: "z <-- (mem (plus (operands[0] << m) t))",
+     where m is 0, 1, or 2 to load address-diff value from table.  */
+  switch (mode)
+    {
+    case QImode:
+      output_asm_insn ("lb\t%2, [$ta + %0 << 0]", operands);
+      break;
+    case HImode:
+      output_asm_insn ("lh\t%2, [$ta + %0 << 1]", operands);
+      break;
+    case SImode:
+      output_asm_insn ("lw\t%2, [$ta + %0 << 2]", operands);
+      break;
+    default:
+      gcc_unreachable ();
+    }
+
+  /* Step E: "t <-- z + t".
+     Add table label_ref with address-diff value to
+     obtain target case address.  */
+  output_asm_insn ("add\t$ta, %2, $ta", operands);
+
+  /* Step F: jump to target with register t.  */
+  if (TARGET_16_BIT)
+    return "jr5\t$ta";
+  else
+    return "jr\t$ta";
+}
+
+/* Function to generate normal jump table.  */
+const char *
+nds32_output_casesi (rtx *operands)
+{
+  /* Step C: "t <-- operands[1]".  */
+  output_asm_insn ("la\t$ta, %l1", operands);
+
+  /* Step D: "z <-- (mem (plus (operands[0] << 2) t))".  */
+  output_asm_insn ("lw\t%2, [$ta + %0 << 2]", operands);
+
+  /* No need to perform Step E, which is only used for
+     pc relative jump table.  */
+
+  /* Step F: jump to target with register z.  */
+  if (TARGET_16_BIT)
+    return "jr5\t%2";
+  else
+    return "jr\t%2";
+}
+
+
+/* Function to return memory format.  */
+enum nds32_16bit_address_type
+nds32_mem_format (rtx op)
+{
+  enum machine_mode mode_test;
+  int val;
+  int regno;
+
+  if (!TARGET_16_BIT)
+    return ADDRESS_NOT_16BIT_FORMAT;
+
+  mode_test = GET_MODE (op);
+
+  op = XEXP (op, 0);
+
+  /* 45 format.  */
+  if (GET_CODE (op) == REG && (mode_test == SImode))
+    return ADDRESS_REG;
+
+  /* 333 format for QI/HImode.  */
+  if (GET_CODE (op) == REG && (REGNO (op) < R8_REGNUM))
+    return ADDRESS_LO_REG_IMM3U;
+
+  /* post_inc 333 format.  */
+  if ((GET_CODE (op) == POST_INC) && (mode_test == SImode))
+    {
+      regno = REGNO(XEXP (op, 0));
+
+      if (regno < 8)
+	return ADDRESS_POST_INC_LO_REG_IMM3U;
+    }
+
+  /* post_inc 333 format.  */
+  if ((GET_CODE (op) == POST_MODIFY)
+      && (mode_test == SImode)
+      && (REG_P (XEXP (XEXP (op, 1), 0)))
+      && (CONST_INT_P (XEXP (XEXP (op, 1), 1))))
+    {
+      regno = REGNO (XEXP (XEXP (op, 1), 0));
+      val = INTVAL (XEXP (XEXP (op, 1), 1));
+      if (regno < 8 && val < 32)
+	return ADDRESS_POST_INC_LO_REG_IMM3U;
+    }
+
+  if ((GET_CODE (op) == PLUS)
+      && (GET_CODE (XEXP (op, 0)) == REG)
+      && (GET_CODE (XEXP (op, 1)) == CONST_INT))
+    {
+      val = INTVAL (XEXP (op, 1));
+
+      regno = REGNO(XEXP (op, 0));
+
+      if (regno > 7
+	  && regno != SP_REGNUM
+	  && regno != FP_REGNUM)
+	return ADDRESS_NOT_16BIT_FORMAT;
+
+      switch (mode_test)
+	{
+	case QImode:
+	  /* 333 format.  */
+	  if (val >= 0 && val < 8 && regno < 8)
+	    return ADDRESS_LO_REG_IMM3U;
+	  break;
+
+	case HImode:
+	  /* 333 format.  */
+	  if (val >= 0 && val < 16 && (val % 2 == 0) && regno < 8)
+	    return ADDRESS_LO_REG_IMM3U;
+	  break;
+
+	case SImode:
+	case SFmode:
+	case DFmode:
+	  /* fp imply 37 format.  */
+	  if ((regno == FP_REGNUM) &&
+	      (val >= 0 && val < 512 && (val % 4 == 0)))
+	    return ADDRESS_FP_IMM7U;
+	  /* sp imply 37 format.  */
+	  else if ((regno == SP_REGNUM) &&
+		   (val >= 0 && val < 512 && (val % 4 == 0)))
+	    return ADDRESS_SP_IMM7U;
+	  /* 333 format.  */
+	  else if (val >= 0 && val < 32 && (val % 4 == 0) && regno < 8)
+	    return ADDRESS_LO_REG_IMM3U;
+	  break;
+
+	default:
+	  break;
+	}
+    }
+
+  return ADDRESS_NOT_16BIT_FORMAT;
+}
+
+/* Output 16-bit store.  */
+const char *
+nds32_output_16bit_store (rtx *operands, int byte)
+{
+  char pattern[100];
+  char size;
+  rtx code = XEXP (operands[0], 0);
+
+  size = nds32_byte_to_size (byte);
+
+  switch (nds32_mem_format (operands[0]))
+    {
+    case ADDRESS_REG:
+      operands[0] = code;
+      output_asm_insn ("swi450\t%1, [%0]", operands);
+      break;
+    case ADDRESS_LO_REG_IMM3U:
+      snprintf (pattern, sizeof (pattern), "s%ci333\t%%1, %%0", size);
+      output_asm_insn (pattern, operands);
+      break;
+    case ADDRESS_POST_INC_LO_REG_IMM3U:
+      snprintf (pattern, sizeof (pattern), "s%ci333.bi\t%%1, %%0", size);
+      output_asm_insn (pattern, operands);
+      break;
+    case ADDRESS_FP_IMM7U:
+      output_asm_insn ("swi37\t%1, %0", operands);
+      break;
+    case ADDRESS_SP_IMM7U:
+      /* Get immediate value and set back to operands[1].  */
+      operands[0] = XEXP (code, 1);
+      output_asm_insn ("swi37.sp\t%1, [ + (%0)]", operands);
+      break;
+    default:
+      break;
+    }
+
+  return "";
+}
+
+/* Output 16-bit load.  */
+const char *
+nds32_output_16bit_load (rtx *operands, int byte)
+{
+  char pattern[100];
+  unsigned char size;
+  rtx code = XEXP (operands[1], 0);
+
+  size = nds32_byte_to_size (byte);
+
+  switch (nds32_mem_format (operands[1]))
+    {
+    case ADDRESS_REG:
+      operands[1] = code;
+      output_asm_insn ("lwi450\t%0, [%1]", operands);
+      break;
+    case ADDRESS_LO_REG_IMM3U:
+      snprintf (pattern, sizeof (pattern), "l%ci333\t%%0, %%1", size);
+      output_asm_insn (pattern, operands);
+      break;
+    case ADDRESS_POST_INC_LO_REG_IMM3U:
+      snprintf (pattern, sizeof (pattern), "l%ci333.bi\t%%0, %%1", size);
+      output_asm_insn (pattern, operands);
+      break;
+    case ADDRESS_FP_IMM7U:
+      output_asm_insn ("lwi37\t%0, %1", operands);
+      break;
+    case ADDRESS_SP_IMM7U:
+      /* Get immediate value and set back to operands[0].  */
+      operands[1] = XEXP (code, 1);
+      output_asm_insn ("lwi37.sp\t%0, [ + (%1)]", operands);
+      break;
+    default:
+      break;
+    }
+
+  return "";
+}
+
+/* Output 32-bit store.  */
+const char *
+nds32_output_32bit_store (rtx *operands, int byte)
+{
+  char pattern[100];
+  unsigned char size;
+  rtx code = XEXP (operands[0], 0);
+
+  size = nds32_byte_to_size (byte);
+
+  switch (GET_CODE (code))
+    {
+    case REG:
+      /* (mem (reg X))
+	 => access location by using register,
+	 use "sbi / shi / swi" */
+      snprintf (pattern, sizeof (pattern), "s%ci\t%%1, %%0", size);
+      break;
+
+    case SYMBOL_REF:
+    case CONST:
+      /* (mem (symbol_ref X))
+	 (mem (const (...)))
+	 => access global variables,
+	 use "sbi.gp / shi.gp / swi.gp" */
+      operands[0] = XEXP (operands[0], 0);
+      snprintf (pattern, sizeof (pattern), "s%ci.gp\t%%1, [ + %%0]", size);
+      break;
+
+    case POST_INC:
+      /* (mem (post_inc reg))
+	 => access location by using register which will be post increment,
+	 use "sbi.bi / shi.bi / swi.bi" */
+      snprintf (pattern, sizeof (pattern),
+		"s%ci.bi\t%%1, %%0, %d", size, byte);
+      break;
+
+    case POST_DEC:
+      /* (mem (post_dec reg))
+	 => access location by using register which will be post decrement,
+	 use "sbi.bi / shi.bi / swi.bi" */
+      snprintf (pattern, sizeof (pattern),
+		"s%ci.bi\t%%1, %%0, -%d", size, byte);
+      break;
+
+    case POST_MODIFY:
+      switch (GET_CODE (XEXP (XEXP (code, 1), 1)))
+	{
+	case REG:
+	case SUBREG:
+	  /* (mem (post_modify (reg) (plus (reg) (reg))))
+	     => access location by using register which will be
+	     post modified with reg,
+	     use "sb.bi/ sh.bi / sw.bi" */
+	  snprintf (pattern, sizeof (pattern), "s%c.bi\t%%1, %%0", size);
+	  break;
+	case CONST_INT:
+	  /* (mem (post_modify (reg) (plus (reg) (const_int))))
+	     => access location by using register which will be
+	     post modified with const_int,
+	     use "sbi.bi/ shi.bi / swi.bi" */
+	  snprintf (pattern, sizeof (pattern), "s%ci.bi\t%%1, %%0", size);
+	  break;
+	default:
+	  abort ();
+	}
+      break;
+
+    case PLUS:
+      switch (GET_CODE (XEXP (code, 1)))
+	{
+	case REG:
+	case SUBREG:
+	  /* (mem (plus reg reg)) or (mem (plus (mult reg const_int) reg))
+	     => access location by adding two registers,
+	     use "sb / sh / sw" */
+	  snprintf (pattern, sizeof (pattern), "s%c\t%%1, %%0", size);
+	  break;
+	case CONST_INT:
+	  /* (mem (plus reg const_int))
+	     => access location by adding one register with const_int,
+	     use "sbi / shi / swi" */
+	  snprintf (pattern, sizeof (pattern), "s%ci\t%%1, %%0", size);
+	  break;
+	default:
+	  abort ();
+	}
+      break;
+
+    case LO_SUM:
+      operands[2] = XEXP (code, 1);
+      operands[0] = XEXP (code, 0);
+      snprintf (pattern, sizeof (pattern),
+		"s%ci\t%%1, [%%0 + lo12(%%2)]", size);
+      break;
+
+    default:
+      abort ();
+    }
+
+  output_asm_insn (pattern, operands);
+  return "";
+}
+
+/* Output 32-bit load.  */
+const char *
+nds32_output_32bit_load (rtx *operands, int byte)
+{
+  char pattern[100];
+  unsigned char size;
+  rtx code;
+
+  code = XEXP (operands[1], 0);
+
+  size = nds32_byte_to_size (byte);
+
+  switch (GET_CODE (code))
+    {
+    case REG:
+      /* (mem (reg X))
+	 => access location by using register,
+	 use "lbi / lhi / lwi" */
+      snprintf (pattern, sizeof (pattern), "l%ci\t%%0, %%1", size);
+      break;
+
+    case SYMBOL_REF:
+    case CONST:
+      /* (mem (symbol_ref X))
+	 (mem (const (...)))
+	 => access global variables,
+	 use "lbi.gp / lhi.gp / lwi.gp" */
+      operands[1] = XEXP (operands[1], 0);
+      snprintf (pattern, sizeof (pattern), "l%ci.gp\t%%0, [ + %%1]", size);
+      break;
+
+    case POST_INC:
+      /* (mem (post_inc reg))
+	 => access location by using register which will be post increment,
+	 use "lbi.bi / lhi.bi / lwi.bi" */
+      snprintf (pattern, sizeof (pattern),
+		"l%ci.bi\t%%0, %%1, %d", size, byte);
+      break;
+
+    case POST_DEC:
+      /* (mem (post_dec reg))
+	 => access location by using register which will be post decrement,
+	 use "lbi.bi / lhi.bi / lwi.bi" */
+      snprintf (pattern, sizeof (pattern),
+		"l%ci.bi\t%%0, %%1, -%d", size, byte);
+      break;
+
+    case POST_MODIFY:
+      switch (GET_CODE (XEXP (XEXP (code, 1), 1)))
+	{
+	case REG:
+	case SUBREG:
+	  /* (mem (post_modify (reg) (plus (reg) (reg))))
+	     => access location by using register which will be
+	     post modified with reg,
+	     use "lb.bi/ lh.bi / lw.bi" */
+	  snprintf (pattern, sizeof (pattern), "l%c.bi\t%%0, %%1", size);
+	  break;
+	case CONST_INT:
+	  /* (mem (post_modify (reg) (plus (reg) (const_int))))
+	     => access location by using register which will be
+	     post modified with const_int,
+	     use "lbi.bi/ lhi.bi / lwi.bi" */
+	  snprintf (pattern, sizeof (pattern), "l%ci.bi\t%%0, %%1", size);
+	  break;
+	default:
+	  abort ();
+	}
+      break;
+
+    case PLUS:
+      switch (GET_CODE (XEXP (code, 1)))
+	{
+	case REG:
+	case SUBREG:
+	  /* (mem (plus reg reg)) or (mem (plus (mult reg const_int) reg))
+	     use "lb / lh / lw" */
+	  snprintf (pattern, sizeof (pattern), "l%c\t%%0, %%1", size);
+	  break;
+	case CONST_INT:
+	  /* (mem (plus reg const_int))
+	     => access location by adding one register with const_int,
+	     use "lbi / lhi / lwi" */
+	  snprintf (pattern, sizeof (pattern), "l%ci\t%%0, %%1", size);
+	  break;
+	default:
+	  abort ();
+	}
+      break;
+
+    case LO_SUM:
+      operands[2] = XEXP (code, 1);
+      operands[1] = XEXP (code, 0);
+      snprintf (pattern, sizeof (pattern),
+		"l%ci\t%%0, [%%1 + lo12(%%2)]", size);
+      break;
+
+    default:
+      abort ();
+    }
+
+  output_asm_insn (pattern, operands);
+  return "";
+}
+
+/* Output 32-bit load with signed extension.  */
+const char *
+nds32_output_32bit_load_s (rtx *operands, int byte)
+{
+  char pattern[100];
+  unsigned char size;
+  rtx code;
+
+  code = XEXP (operands[1], 0);
+
+  size = nds32_byte_to_size (byte);
+
+  switch (GET_CODE (code))
+    {
+    case REG:
+      /* (mem (reg X))
+         => access location by using register,
+         use "lbsi / lhsi" */
+      snprintf (pattern, sizeof (pattern), "l%csi\t%%0, %%1", size);
+      break;
+
+    case SYMBOL_REF:
+    case CONST:
+      /* (mem (symbol_ref X))
+         (mem (const (...)))
+         => access global variables,
+         use "lbsi.gp / lhsi.gp" */
+      operands[1] = XEXP (operands[1], 0);
+      snprintf (pattern, sizeof (pattern), "l%csi.gp\t%%0, [ + %%1]", size);
+      break;
+
+    case POST_INC:
+      /* (mem (post_inc reg))
+         => access location by using register which will be post increment,
+         use "lbsi.bi / lhsi.bi" */
+      snprintf (pattern, sizeof (pattern),
+		"l%csi.bi\t%%0, %%1, %d", size, byte);
+      break;
+
+    case POST_DEC:
+      /* (mem (post_dec reg))
+         => access location by using register which will be post decrement,
+         use "lbsi.bi / lhsi.bi" */
+      snprintf (pattern, sizeof (pattern),
+		"l%csi.bi\t%%0, %%1, -%d", size, byte);
+      break;
+
+    case POST_MODIFY:
+      switch (GET_CODE (XEXP (XEXP (code, 1), 1)))
+	{
+	case REG:
+	case SUBREG:
+	  /* (mem (post_modify (reg) (plus (reg) (reg))))
+	     => access location by using register which will be
+	     post modified with reg,
+	     use "lbs.bi/ lhs.bi" */
+	  snprintf (pattern, sizeof (pattern), "l%cs.bi\t%%0, %%1", size);
+	  break;
+	case CONST_INT:
+	  /* (mem (post_modify (reg) (plus (reg) (const_int))))
+	     => access location by using register which will be
+	     post modified with const_int,
+	     use "lbsi.bi/ lhsi.bi" */
+	  snprintf (pattern, sizeof (pattern), "l%csi.bi\t%%0, %%1", size);
+	  break;
+	default:
+	  abort ();
+	}
+      break;
+
+    case PLUS:
+      switch (GET_CODE (XEXP (code, 1)))
+	{
+	case REG:
+	case SUBREG:
+	  /* (mem (plus reg reg)) or (mem (plus (mult reg const_int) reg))
+	     use "lbs / lhs" */
+	  snprintf (pattern, sizeof (pattern), "l%cs\t%%0, %%1", size);
+	  break;
+	case CONST_INT:
+	  /* (mem (plus reg const_int))
+	     => access location by adding one register with const_int,
+	     use "lbsi / lhsi" */
+	  snprintf (pattern, sizeof (pattern), "l%csi\t%%0, %%1", size);
+	  break;
+	default:
+	  abort ();
+	}
+      break;
+
+    case LO_SUM:
+      operands[2] = XEXP (code, 1);
+      operands[1] = XEXP (code, 0);
+      snprintf (pattern, sizeof (pattern),
+		"l%csi\t%%0, [%%1 + lo12(%%2)]", size);
+      break;
+
+    default:
+      abort ();
+    }
+
+  output_asm_insn (pattern, operands);
+  return "";
+}
+
+/* Return align 2 (log base 2) if the next instruction of LABEL is 4 byte.  */
+int
+nds32_target_alignment (rtx label)
+{
+  rtx insn;
+
+  if (optimize_size)
+    return 0;
+
+  insn = next_active_insn (label);
+
+  if (insn == 0)
+    return 0;
+  else if ((get_attr_length (insn) % 4) == 0)
+    return 2;
+  else
+    return 0;
+}
+
+/* ------------------------------------------------------------------------ */
+
+/* PART 5: Initialize target hook structure and definitions.  */
+
+/* Controlling the Compilation Driver.  */
+
+
+/* Run-time Target Specification.  */
+
+
+/* Defining Data Structures for Per-function Information.  */
+
+
+/* Storage Layout.  */
+
+#undef TARGET_PROMOTE_FUNCTION_MODE
+#define TARGET_PROMOTE_FUNCTION_MODE \
+  default_promote_function_mode_always_promote
+
+
+/* Layout of Source Language Data Types.  */
+
+
+/* Register Usage.  */
+
+/* -- Basic Characteristics of Registers.  */
+
+/* -- Order of Allocation of Registers.  */
+
+/* -- How Values Fit in Registers.  */
+
+/* -- Handling Leaf Functions.  */
+
+/* -- Registers That Form a Stack.  */
+
+
+/* Register Classes.  */
+
+#undef TARGET_CLASS_MAX_NREGS
+#define TARGET_CLASS_MAX_NREGS nds32_class_max_nregs
+
+#undef TARGET_LRA_P
+#define TARGET_LRA_P hook_bool_void_true
+
+#undef TARGET_REGISTER_PRIORITY
+#define TARGET_REGISTER_PRIORITY nds32_register_priority
+
+
+/* Obsolete Macros for Defining Constraints.  */
+
+
+/* Stack Layout and Calling Conventions.  */
+
+/* -- Basic Stack Layout.  */
+
+/* -- Exception Handling Support.  */
+
+/* -- Specifying How Stack Checking is Done.  */
+
+/* -- Registers That Address the Stack Frame.  */
+
+/* -- Eliminating Frame Pointer and Arg Pointer.  */
+
+#undef TARGET_CAN_ELIMINATE
+#define TARGET_CAN_ELIMINATE nds32_can_eliminate
+
+/* -- Passing Function Arguments on the Stack.  */
+
+/* -- Passing Arguments in Registers.  */
+
+#undef TARGET_FUNCTION_ARG
+#define TARGET_FUNCTION_ARG nds32_function_arg
+
+#undef TARGET_FUNCTION_ARG_ADVANCE
+#define TARGET_FUNCTION_ARG_ADVANCE nds32_function_arg_advance
+
+#undef TARGET_FUNCTION_ARG_BOUNDARY
+#define TARGET_FUNCTION_ARG_BOUNDARY nds32_function_arg_boundary
+
+/* -- How Scalar Function Values Are Returned.  */
+
+#undef TARGET_FUNCTION_VALUE
+#define TARGET_FUNCTION_VALUE nds32_function_value
+
+#undef TARGET_LIBCALL_VALUE
+#define TARGET_LIBCALL_VALUE nds32_libcall_value
+
+#undef TARGET_FUNCTION_VALUE_REGNO_P
+#define TARGET_FUNCTION_VALUE_REGNO_P nds32_function_value_regno_p
+
+/* -- How Large Values Are Returned.  */
+
+/* -- Caller-Saves Register Allocation.  */
+
+/* -- Function Entry and Exit.  */
+
+#undef TARGET_ASM_FUNCTION_PROLOGUE
+#define TARGET_ASM_FUNCTION_PROLOGUE nds32_asm_function_prologue
+
+#undef TARGET_ASM_FUNCTION_END_PROLOGUE
+#define TARGET_ASM_FUNCTION_END_PROLOGUE nds32_asm_function_end_prologue
+
+#undef  TARGET_ASM_FUNCTION_BEGIN_EPILOGUE
+#define TARGET_ASM_FUNCTION_BEGIN_EPILOGUE nds32_asm_function_begin_epilogue
+
+#undef TARGET_ASM_FUNCTION_EPILOGUE
+#define TARGET_ASM_FUNCTION_EPILOGUE nds32_asm_function_epilogue
+
+#undef TARGET_ASM_OUTPUT_MI_THUNK
+#define TARGET_ASM_OUTPUT_MI_THUNK nds32_asm_output_mi_thunk
+
+#undef TARGET_ASM_CAN_OUTPUT_MI_THUNK
+#define TARGET_ASM_CAN_OUTPUT_MI_THUNK default_can_output_mi_thunk_no_vcall
+
+/* -- Generating Code for Profiling.  */
+
+/* -- Permitting tail calls.  */
+
+#undef TARGET_WARN_FUNC_RETURN
+#define TARGET_WARN_FUNC_RETURN nds32_warn_func_return
+
+/* Stack smashing protection.  */
+
+
+/* Implementing the Varargs Macros.  */
+
+#undef TARGET_STRICT_ARGUMENT_NAMING
+#define TARGET_STRICT_ARGUMENT_NAMING nds32_strict_argument_naming
+
+
+/* Trampolines for Nested Functions.  */
+
+#undef TARGET_ASM_TRAMPOLINE_TEMPLATE
+#define TARGET_ASM_TRAMPOLINE_TEMPLATE nds32_asm_trampoline_template
+
+#undef TARGET_TRAMPOLINE_INIT
+#define TARGET_TRAMPOLINE_INIT nds32_trampoline_init
+
+
+/* Implicit Calls to Library Routines.  */
+
+
+/* Addressing Modes.  */
+
+#undef TARGET_LEGITIMATE_ADDRESS_P
+#define TARGET_LEGITIMATE_ADDRESS_P nds32_legitimate_address_p
+
+
+/* Anchored Addresses.  */
+
+
+/* Condition Code Status.  */
+
+/* -- Representation of condition codes using (cc0).  */
+
+/* -- Representation of condition codes using registers.  */
+
+/* -- Macros to control conditional execution.  */
+
+
+/* Describing Relative Costs of Operations.  */
+
+#undef TARGET_REGISTER_MOVE_COST
+#define TARGET_REGISTER_MOVE_COST nds32_register_move_cost
+
+#undef TARGET_MEMORY_MOVE_COST
+#define TARGET_MEMORY_MOVE_COST nds32_memory_move_cost
+
+#undef TARGET_RTX_COSTS
+#define TARGET_RTX_COSTS nds32_rtx_costs
+
+#undef TARGET_ADDRESS_COST
+#define TARGET_ADDRESS_COST nds32_address_cost
+
+
+/* Adjusting the Instruction Scheduler.  */
+
+
+/* Dividing the Output into Sections (Texts, Data, . . . ).  */
+
+
+/* Position Independent Code.  */
+
+
+/* Defining the Output Assembler Language.  */
+
+/* -- The Overall Framework of an Assembler File.  */
+
+#undef TARGET_ASM_FILE_START
+#define TARGET_ASM_FILE_START nds32_asm_file_start
+#undef TARGET_ASM_FILE_END
+#define TARGET_ASM_FILE_END nds32_asm_file_end
+
+/* -- Output of Data.  */
+
+#undef TARGET_ASM_ALIGNED_HI_OP
+#define TARGET_ASM_ALIGNED_HI_OP "\t.hword\t"
+
+#undef TARGET_ASM_ALIGNED_SI_OP
+#define TARGET_ASM_ALIGNED_SI_OP "\t.word\t"
+
+/* -- Output of Uninitialized Variables.  */
+
+/* -- Output and Generation of Labels.  */
+
+#undef TARGET_ASM_GLOBALIZE_LABEL
+#define TARGET_ASM_GLOBALIZE_LABEL nds32_asm_globalize_label
+
+/* -- How Initialization Functions Are Handled.  */
+
+/* -- Macros Controlling Initialization Routines.  */
+
+/* -- Output of Assembler Instructions.  */
+
+#undef TARGET_PRINT_OPERAND
+#define TARGET_PRINT_OPERAND nds32_print_operand
+#undef TARGET_PRINT_OPERAND_ADDRESS
+#define TARGET_PRINT_OPERAND_ADDRESS nds32_print_operand_address
+
+/* -- Output of Dispatch Tables.  */
+
+/* -- Assembler Commands for Exception Regions.  */
+
+/* -- Assembler Commands for Alignment.  */
+
+
+/* Controlling Debugging Information Format.  */
+
+/* -- Macros Affecting All Debugging Formats.  */
+
+/* -- Specific Options for DBX Output.  */
+
+/* -- Open-Ended Hooks for DBX Format.  */
+
+/* -- File Names in DBX Format.  */
+
+/* -- Macros for SDB and DWARF Output.  */
+
+/* -- Macros for VMS Debug Format.  */
+
+
+/* Cross Compilation and Floating Point.  */
+
+
+/* Mode Switching Instructions.  */
+
+
+/* Defining target-specific uses of __attribute__.  */
+
+#undef TARGET_ATTRIBUTE_TABLE
+#define TARGET_ATTRIBUTE_TABLE nds32_attribute_table
+
+#undef TARGET_MERGE_DECL_ATTRIBUTES
+#define TARGET_MERGE_DECL_ATTRIBUTES nds32_merge_decl_attributes
+
+#undef TARGET_INSERT_ATTRIBUTES
+#define TARGET_INSERT_ATTRIBUTES nds32_insert_attributes
+
+#undef TARGET_OPTION_PRAGMA_PARSE
+#define TARGET_OPTION_PRAGMA_PARSE nds32_option_pragma_parse
+
+#undef TARGET_OPTION_OVERRIDE
+#define TARGET_OPTION_OVERRIDE nds32_option_override
+
+
+/* Emulating TLS.  */
+
+
+/* Defining coprocessor specifics for MIPS targets.  */
+
+
+/* Parameters for Precompiled Header Validity Checking.  */
+
+
+/* C++ ABI parameters.  */
+
+
+/* Adding support for named address spaces.  */
+
+
+/* Miscellaneous Parameters.  */
+
+#undef TARGET_INIT_BUILTINS
+#define TARGET_INIT_BUILTINS nds32_init_builtins
+
+#undef TARGET_EXPAND_BUILTIN
+#define TARGET_EXPAND_BUILTIN nds32_expand_builtin
+
+
+/* ------------------------------------------------------------------------ */
+
+/* Initialize the GCC target structure.  */
+
+struct gcc_target targetm = TARGET_INITIALIZER;
+
+/* ------------------------------------------------------------------------ */
diff --git gcc/config/nds32/nds32.h gcc/config/nds32/nds32.h
new file mode 100644
index 0000000..36bb9fe
--- /dev/null
+++ gcc/config/nds32/nds32.h
@@ -0,0 +1,982 @@
+/* Definitions of target machine of Andes NDS32 cpu for GNU compiler
+   Copyright (C) 2012-2013 Free Software Foundation, Inc.
+   Contributed by Andes Technology Corporation.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 3, or (at your
+   option) any later version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+
+/* ------------------------------------------------------------------------ */
+
+/* The following are auxiliary macros or structure declarations
+   that are used all over the nds32.c and nds32.h.  */
+
+
+/* Computing the Length of an Insn.  */
+#define ADJUST_INSN_LENGTH(INSN, LENGTH) \
+  (LENGTH = nds32_adjust_insn_length (INSN, LENGTH))
+
+/* Check instruction LS-37-FP-implied form.
+   Note: actually its immediate range is imm9u
+         since it is used for lwi37/swi37 instructions.  */
+#define NDS32_LS_37_FP_P(rt, ra, imm)       \
+  (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS \
+   && REGNO (ra) == FP_REGNUM               \
+   && satisfies_constraint_Iu09 (imm))
+
+/* Check instruction LS-37-SP-implied form.
+   Note: actually its immediate range is imm9u
+         since it is used for lwi37/swi37 instructions.  */
+#define NDS32_LS_37_SP_P(rt, ra, imm)       \
+  (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS \
+   && REGNO (ra) == SP_REGNUM               \
+   && satisfies_constraint_Iu09 (imm))
+
+
+/* Check load/store instruction form : Rt3, Ra3, imm3u.  */
+#define NDS32_LS_333_P(rt, ra, imm, mode) nds32_ls_333_p (rt, ra, imm, mode)
+
+/* Check load/store instruction form : Rt4, Ra5, const_int_0.
+   Note: no need to check ra because Ra5 means it covers all registers.  */
+#define NDS32_LS_450_P(rt, ra, imm)                     \
+  ((imm == const0_rtx)                                  \
+   && (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS         \
+       || REGNO_REG_CLASS (REGNO (rt)) == MIDDLE_REGS))
+
+/* Check instruction RRI-333-form.  */
+#define NDS32_RRI_333_P(rt, ra, imm)           \
+  (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS    \
+   && REGNO_REG_CLASS (REGNO (ra)) == LOW_REGS \
+   && satisfies_constraint_Iu03 (imm))
+
+/* Check instruction RI-45-form.  */
+#define NDS32_RI_45_P(rt, ra, imm)                     \
+  (REGNO (rt) == REGNO (ra)                            \
+   && (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS        \
+       || REGNO_REG_CLASS (REGNO (rt)) == MIDDLE_REGS) \
+   && satisfies_constraint_Iu05 (imm))
+
+
+/* Check instruction RR-33-form.  */
+#define NDS32_RR_33_P(rt, ra)                   \
+  (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS     \
+   && REGNO_REG_CLASS (REGNO (ra)) == LOW_REGS)
+
+/* Check instruction RRR-333-form.  */
+#define NDS32_RRR_333_P(rt, ra, rb)             \
+  (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS     \
+   && REGNO_REG_CLASS (REGNO (ra)) == LOW_REGS  \
+   && REGNO_REG_CLASS (REGNO (rb)) == LOW_REGS)
+
+/* Check instruction RR-45-form.
+   Note: no need to check rb because Rb5 means it covers all registers.  */
+#define NDS32_RR_45_P(rt, ra, rb)               \
+  (REGNO (rt) == REGNO (ra)                     \
+   && (REGNO_REG_CLASS (REGNO (rt)) == LOW_REGS \
+       || REGNO_REG_CLASS (REGNO (rt)) == MIDDLE_REGS))
+
+/* Classifies address type to distinguish 16-bit/32-bit format.  */
+enum nds32_16bit_address_type
+{
+  /* [reg]: 45 format address.  */
+  ADDRESS_REG,
+  /* [lo_reg + imm3u]: 333 format address.  */
+  ADDRESS_LO_REG_IMM3U,
+  /* post_inc [lo_reg + imm3u]: 333 format address.  */
+  ADDRESS_POST_INC_LO_REG_IMM3U,
+  /* [$fp + imm7u]: fp imply address.  */
+  ADDRESS_FP_IMM7U,
+  /* [$sp + imm7u]: sp imply address.  */
+  ADDRESS_SP_IMM7U,
+  /* Other address format.  */
+  ADDRESS_NOT_16BIT_FORMAT
+};
+
+
+/* ------------------------------------------------------------------------ */
+
+/* Define maximum numbers of registers for passing arguments.  */
+#define NDS32_MAX_REGS_FOR_ARGS 6
+
+/* Define the register number for first argument.  */
+#define NDS32_GPR_ARG_FIRST_REGNUM 0
+
+/* Define the register number for return value.  */
+#define NDS32_GPR_RET_FIRST_REGNUM 0
+
+
+/* Define double word alignment bits.  */
+#define NDS32_DOUBLE_WORD_ALIGNMENT 64
+
+/* Define alignment checking macros for convenience.  */
+#define NDS32_HALF_WORD_ALIGN_P(value)   (((value) & 0x01) == 0)
+#define NDS32_SINGLE_WORD_ALIGN_P(value) (((value) & 0x03) == 0)
+#define NDS32_DOUBLE_WORD_ALIGN_P(value) (((value) & 0x07) == 0)
+
+/* Round X up to the nearest double word.  */
+#define NDS32_ROUND_UP_DOUBLE_WORD(value)  (((value) + 7) & ~7)
+
+
+/* This macro is used to calculate the numbers of registers for
+   containing 'size' bytes of the argument.
+   The size of a register is a word in nds32 target.
+   So we use UNITS_PER_WORD to do the calculation.  */
+#define NDS32_NEED_N_REGS_FOR_ARG(mode, type)                            \
+  ((mode == BLKmode)                                                     \
+   ? ((int_size_in_bytes (type) + UNITS_PER_WORD - 1) / UNITS_PER_WORD)  \
+   : ((GET_MODE_SIZE (mode)     + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
+
+/* This macro is used to return the register number for passing argument.
+   We need to obey the following rules:
+     1. If it is required MORE THAN one register,
+        make sure the register number is a even value.
+     2. If it is required ONLY one register,
+        the register number can be odd or even value.  */
+#define NDS32_AVAILABLE_REGNUM_FOR_ARG(reg_offset, mode, type) \
+  ((NDS32_NEED_N_REGS_FOR_ARG (mode, type) > 1)                \
+   ? (((reg_offset) + NDS32_GPR_ARG_FIRST_REGNUM + 1) & ~1)    \
+   : ((reg_offset) + NDS32_GPR_ARG_FIRST_REGNUM))
+
+/* This macro is to check if there are still available registers
+   for passing argument.  */
+#define NDS32_ARG_PASS_IN_REG_P(reg_offset, mode, type)      \
+  (((reg_offset) < NDS32_MAX_REGS_FOR_ARGS)                  \
+   && ((reg_offset) + NDS32_NEED_N_REGS_FOR_ARG (mode, type) \
+       <= NDS32_MAX_REGS_FOR_ARGS))
+
+/* This macro is to check if the register is required to be saved on stack.
+   If call_used_regs[regno] == 0, regno is the callee-saved register.
+   If df_regs_ever_live_p(regno) == true, it is used in the current function.
+   As long as the register satisfies both criteria above,
+   it is required to be saved.  */
+#define NDS32_REQUIRED_CALLEE_SAVED_P(regno)                  \
+  ((!call_used_regs[regno]) && (df_regs_ever_live_p (regno)))
+
+/* ------------------------------------------------------------------------ */
+
+/* A C structure for machine-specific, per-function data.
+   This is added to the cfun structure.  */
+struct GTY(()) machine_function
+{
+  /* Number of bytes allocated on the stack for variadic args
+     if we want to push them into stack as pretend arguments by ourself.  */
+  int va_args_size;
+  /* Number of bytes reserved on the stack for
+     local and temporary variables.  */
+  int local_size;
+  /* Number of bytes allocated on the stack for outgoing arguments.  */
+  int out_args_size;
+
+  /* Number of bytes on the stack for saving $fp.  */
+  int fp_size;
+  /* Number of bytes on the stack for saving $gp.  */
+  int gp_size;
+  /* Number of bytes on the stack for saving $lp.  */
+  int lp_size;
+
+  /* Number of bytes on the stack for saving callee-saved registers.  */
+  int callee_saved_regs_size;
+  /* The padding bytes in callee-saved area may be required.  */
+  int callee_saved_area_padding_bytes;
+
+  /* The first required register that should be saved on stack
+     for va_args (one named argument + nameless arguments).  */
+  int va_args_first_regno;
+  /* The last required register that should be saved on stack
+     for va_args (one named argument + nameless arguments).  */
+  int va_args_last_regno;
+
+  /* The first required callee-saved register.  */
+  int callee_saved_regs_first_regno;
+  /* The last required callee-saved register.  */
+  int callee_saved_regs_last_regno;
+
+  /* Indicate that whether this function needs
+     prologue/epilogue code generation.  */
+  int naked_p;
+  /* Indicate that whether this function
+     uses fp_as_gp optimization.  */
+  int fp_as_gp_p;
+};
+
+/* A C structure that contains the arguments information.  */
+typedef struct
+{
+  unsigned int reg_offset;
+} nds32_cumulative_args;
+
+/* ------------------------------------------------------------------------ */
+
+/* The following we define C-ISR related stuff.
+   In nds32 architecture, we have 73 vectors for interrupt/exception.
+   For each vector (except for vector 0, which is used for reset behavior),
+   we allow users to set its register saving scheme and interrupt level.  */
+
+/* There are 73 vectors in nds32 architecture.
+   0 for reset handler,
+   1-8 for exception handler,
+   and 9-72 for interrupt handler.
+   We use an array, which is defined in nds32.c, to record
+   essential information for each vector.  */
+#define NDS32_N_ISR_VECTORS 73
+
+/* Define possible isr category.  */
+enum nds32_isr_category
+{
+  NDS32_ISR_NONE,
+  NDS32_ISR_INTERRUPT,
+  NDS32_ISR_EXCEPTION,
+  NDS32_ISR_RESET
+};
+
+/* Define isr register saving scheme.  */
+enum nds32_isr_save_reg
+{
+  NDS32_SAVE_ALL,
+  NDS32_PARTIAL_SAVE
+};
+
+/* Define isr nested type.  */
+enum nds32_isr_nested_type
+{
+  NDS32_NESTED,
+  NDS32_NOT_NESTED,
+  NDS32_NESTED_READY
+};
+
+/* Define structure to record isr information.
+   The isr vector array 'isr_vectors[]' with this structure
+   is defined in nds32.c.  */
+struct nds32_isr_info
+{
+  /* The field to identify isr category.
+     It should be set to NDS32_ISR_NONE by default.
+     If user specifies a function as isr by using attribute,
+     this field will be set accordingly.  */
+  enum nds32_isr_category category;
+
+  /* A string for the applied function name.
+     It should be set to empty string by default.  */
+  char func_name[100];
+
+  /* The register saving scheme.
+     It should be set to NDS32_PARTIAL_SAVE by default
+     unless user specifies attribute to change it.  */
+  enum nds32_isr_save_reg save_reg;
+
+  /* The nested type.
+     It should be set to NDS32_NOT_NESTED by default
+     unless user specifies attribute to change it.  */
+  enum nds32_isr_nested_type nested_type;
+
+  /* Total vectors.
+     The total vectors = interrupt + exception numbers + reset.
+     It should be set to 0 by default.
+     This field is ONLY used in NDS32_ISR_RESET category.  */
+  unsigned int total_n_vectors;
+
+  /* A string for nmi handler name.
+     It should be set to empty string by default.
+     This field is ONLY used in NDS32_ISR_RESET category.  */
+  char nmi_name[100];
+
+  /* A string for warm handler name.
+     It should be set to empty string by default.
+     This field is ONLY used in NDS32_ISR_RESET category.  */
+  char warm_name[100];
+};
+
+/* ------------------------------------------------------------------------ */
+
+/* Define code for all nds32 builtins.  */
+enum nds32_builtins
+{
+  NDS32_BUILTIN_ISYNC,
+  NDS32_BUILTIN_ISB,
+  NDS32_BUILTIN_MFSR,
+  NDS32_BUILTIN_MFUSR,
+  NDS32_BUILTIN_MTSR,
+  NDS32_BUILTIN_MTUSR,
+  NDS32_BUILTIN_SETGIE_EN,
+  NDS32_BUILTIN_SETGIE_DIS
+};
+
+/* ------------------------------------------------------------------------ */
+
+#define TARGET_ISA_V2   (nds32_arch_option == ARCH_V2)
+#define TARGET_ISA_V3   (nds32_arch_option == ARCH_V3)
+#define TARGET_ISA_V3M  (nds32_arch_option == ARCH_V3M)
+
+/* ------------------------------------------------------------------------ */
+
+/* Controlling the Compilation Driver.  */
+
+#define OPTION_DEFAULT_SPECS \
+  {"arch", "%{!march=*:-march=%(VALUE)}" }
+
+#define CC1_SPEC \
+  ""
+
+#define ASM_SPEC \
+  " %{mbig-endian:-EB} %{mlittle-endian:-EL}"
+
+/* If user issues -mrelax, -mforce-fp-as-gp, or -mex9,
+   we need to pass '--relax' to linker.
+   Besides, for -mex9, we need to further pass '--mex9'.  */
+#define LINK_SPEC \
+  " %{mbig-endian:-EB} %{mlittle-endian:-EL}" \
+  " %{mrelax|mforce-fp-as-gp|mex9:--relax}" \
+  " %{mex9:--mex9}"
+
+#define LIB_SPEC \
+  " -lc -lgloss"
+
+/* The option -mno-ctor-dtor can disable constructor/destructor feature
+   by applying different crt stuff.  In the convention, crt0.o is the
+   startup file without constructor/desctructor;
+   crt1.o, crti.o, crtbegin.o, crtend.o, and crtn.o are the
+   startup files with constructor/destructor.
+   Note that crt0.o, crt1.o, crti.o, and crtn.o are provided
+   by newlib/mculib/glibc/ublic, while crtbegin.o and crtend.o are
+   currently provided by GCC for nds32 target.
+
+   For nds32 target so far:
+   If -mno-ctor-dtor, we are going to link
+   "crt0.o [user objects]".
+   If general cases, we are going to link
+   "crt1.o crtbegin1.o [user objects] crtend1.o".  */
+#define STARTFILE_SPEC \
+  " %{!mno-ctor-dtor:crt1.o%s;:crt0.o%s}" \
+  " %{!mno-ctor-dtor:crtbegin1.o%s}"
+#define ENDFILE_SPEC \
+  " %{!mno-ctor-dtor:crtend1.o%s}"
+
+/* The TARGET_BIG_ENDIAN_DEFAULT is defined if we configure gcc
+   with --target=nds32be-* setting.
+   Check gcc/config.gcc for more information.
+   In addition, currently we only have elf toolchain,
+   where mgp-direct is always the default.  */
+#ifdef TARGET_BIG_ENDIAN_DEFAULT
+#define MULTILIB_DEFAULTS { "mbig-endian", "mgp-direct" }
+#else
+#define MULTILIB_DEFAULTS { "mlittle-endian", "mgp-direct" }
+#endif
+
+
+/* Run-time Target Specification.  */
+
+#define TARGET_CPU_CPP_BUILTINS()                     \
+  do                                                  \
+    {                                                 \
+      builtin_define ("__nds32__");                   \
+                                                      \
+      if (TARGET_ISA_V2)                              \
+        builtin_define ("__NDS32_ISA_V2__");          \
+      if (TARGET_ISA_V3)                              \
+        builtin_define ("__NDS32_ISA_V3__");          \
+      if (TARGET_ISA_V3M)                             \
+        builtin_define ("__NDS32_ISA_V3M__");         \
+                                                      \
+      if (TARGET_BIG_ENDIAN)                          \
+        builtin_define ("__big_endian__");            \
+      if (TARGET_REDUCED_REGS)                        \
+        builtin_define ("__NDS32_REDUCED_REGS__");    \
+      if (TARGET_CMOV)                                \
+        builtin_define ("__NDS32_CMOV__");            \
+      if (TARGET_PERF_EXT)                            \
+        builtin_define ("__NDS32_PERF_EXT__");        \
+      if (TARGET_16_BIT)                              \
+        builtin_define ("__NDS32_16_BIT__");          \
+      if (TARGET_GP_DIRECT)                           \
+        builtin_define ("__NDS32_GP_DIRECT__");       \
+                                                      \
+      builtin_assert ("cpu=nds32");                   \
+      builtin_assert ("machine=nds32");               \
+    } while (0)
+
+
+/* Defining Data Structures for Per-function Information.  */
+
+/* This macro is called once per function,
+   before generation of any RTL has begun.  */
+#define INIT_EXPANDERS  nds32_init_expanders ()
+
+
+/* Storage Layout.  */
+
+#define BITS_BIG_ENDIAN 0
+
+#define BYTES_BIG_ENDIAN (TARGET_BIG_ENDIAN)
+
+#define WORDS_BIG_ENDIAN (TARGET_BIG_ENDIAN)
+
+#define UNITS_PER_WORD 4
+
+#define PROMOTE_MODE(m, unsignedp, type)                                    \
+  if (GET_MODE_CLASS (m) == MODE_INT && GET_MODE_SIZE (m) < UNITS_PER_WORD) \
+    {                                                                       \
+      (m) = SImode;                                                         \
+    }
+
+#define PARM_BOUNDARY 32
+
+#define STACK_BOUNDARY 64
+
+#define FUNCTION_BOUNDARY 32
+
+#define BIGGEST_ALIGNMENT 64
+
+#define EMPTY_FIELD_BOUNDARY 32
+
+#define STRUCTURE_SIZE_BOUNDARY 8
+
+#define STRICT_ALIGNMENT 1
+
+#define PCC_BITFIELD_TYPE_MATTERS 1
+
+
+/* Layout of Source Language Data Types.  */
+
+#define INT_TYPE_SIZE           32
+#define SHORT_TYPE_SIZE         16
+#define LONG_TYPE_SIZE          32
+#define LONG_LONG_TYPE_SIZE     64
+
+#define FLOAT_TYPE_SIZE         32
+#define DOUBLE_TYPE_SIZE        64
+#define LONG_DOUBLE_TYPE_SIZE   64
+
+#define DEFAULT_SIGNED_CHAR 1
+
+#define SIZE_TYPE "long unsigned int"
+#define PTRDIFF_TYPE "long int"
+#define WCHAR_TYPE "short unsigned int"
+#define WCHAR_TYPE_SIZE 16
+
+
+/* Register Usage.  */
+
+/* Number of actual hardware registers.
+   The hardware registers are assigned numbers for the compiler
+   from 0 to just below FIRST_PSEUDO_REGISTER.
+   All registers that the compiler knows about must be given numbers,
+   even those that are not normally considered general registers.  */
+#define FIRST_PSEUDO_REGISTER 34
+
+/* An initializer that says which registers are used for fixed
+   purposes all throughout the compiled code and are therefore
+   not available for general allocation.
+
+   $r28 : $fp
+   $r29 : $gp
+   $r30 : $lp
+   $r31 : $sp
+
+   caller-save registers: $r0 ~ $r5, $r16 ~ $r23
+   callee-save registers: $r6 ~ $r10, $r11 ~ $r14
+
+   reserved for assembler : $r15
+   reserved for other use : $r24, $r25, $r26, $r27 */
+#define FIXED_REGISTERS                 \
+{ /* r0  r1  r2  r3  r4  r5  r6  r7  */ \
+      0,  0,  0,  0,  0,  0,  0,  0,    \
+  /* r8  r9  r10 r11 r12 r13 r14 r15 */ \
+      0,  0,  0,  0,  0,  0,  0,  1,    \
+  /* r16 r17 r18 r19 r20 r21 r22 r23 */ \
+      0,  0,  0,  0,  0,  0,  0,  0,    \
+  /* r24 r25 r26 r27 r28 r29 r30 r31 */ \
+      1,  1,  1,  1,  0,  1,  0,  1,    \
+  /* ARG_POINTER:32 */                  \
+      1,                                \
+  /* FRAME_POINTER:33 */                \
+      1                                 \
+}
+
+/* Identifies the registers that are not available for
+   general allocation of values that must live across
+   function calls -- so they are caller-save registers.
+
+   0 : callee-save registers
+   1 : caller-save registers */
+#define CALL_USED_REGISTERS             \
+{ /* r0  r1  r2  r3  r4  r5  r6  r7  */ \
+      1,  1,  1,  1,  1,  1,  0,  0,    \
+  /* r8  r9  r10 r11 r12 r13 r14 r15 */ \
+      0,  0,  0,  0,  0,  0,  0,  1,    \
+  /* r16 r17 r18 r19 r20 r21 r22 r23 */ \
+      1,  1,  1,  1,  1,  1,  1,  1,    \
+  /* r24 r25 r26 r27 r28 r29 r30 r31 */ \
+      1,  1,  1,  1,  0,  1,  0,  1,    \
+  /* ARG_POINTER:32 */                  \
+      1,                                \
+  /* FRAME_POINTER:33 */                \
+      1                                 \
+}
+
+/* In nds32 target, we have three levels of registers:
+     LOW_COST_REGS    : $r0 ~ $r7
+     MIDDLE_COST_REGS : $r8 ~ $r11, $r16 ~ $r19
+     HIGH_COST_REGS   : $r12 ~ $r14, $r20 ~ $r31 */
+#define REG_ALLOC_ORDER           \
+{                                 \
+   0,  1,  2,  3,  4,  5,  6,  7, \
+   8,  9, 10, 11, 16, 17, 18, 19, \
+  12, 13, 14, 15, 20, 21, 22, 23, \
+  24, 25, 26, 27, 28, 29, 30, 31, \
+  32,                             \
+  33                              \
+}
+
+/* Tell IRA to use the order we define rather than messing it up with its
+   own cost calculations.  */
+#define HONOR_REG_ALLOC_ORDER
+
+/* The number of consecutive hard regs needed starting at
+   reg "regno" for holding a value of mode "mode".  */
+#define HARD_REGNO_NREGS(regno, mode) nds32_hard_regno_nregs (regno, mode)
+
+/* Value is 1 if hard register "regno" can hold a value
+   of machine-mode "mode".  */
+#define HARD_REGNO_MODE_OK(regno, mode) nds32_hard_regno_mode_ok (regno, mode)
+
+/* A C expression that is nonzero if a value of mode1
+   is accessible in mode2 without copying.
+   Define this macro to return nonzero in as many cases as possible
+   since doing so will allow GCC to perform better register allocation.
+   We can use general registers to tie QI/HI/SI modes together.  */
+#define MODES_TIEABLE_P(mode1, mode2)          \
+  (GET_MODE_CLASS (mode1) == MODE_INT          \
+   && GET_MODE_CLASS (mode2) == MODE_INT       \
+   && GET_MODE_SIZE (mode1) <= UNITS_PER_WORD  \
+   && GET_MODE_SIZE (mode2) <= UNITS_PER_WORD)
+
+
+/* Register Classes.  */
+
+/* In nds32 target, we have three levels of registers:
+     Low cost regsiters    : $r0 ~ $r7
+     Middle cost registers : $r8 ~ $r11, $r16 ~ $r19
+     High cost registers   : $r12 ~ $r14, $r20 ~ $r31
+
+   In practice, we have MIDDLE_REGS cover LOW_REGS register class contents
+   so that it provides more chance to use low cost registers.  */
+enum reg_class
+{
+  NO_REGS,
+  R15_TA_REG,
+  STACK_REG,
+  LOW_REGS,
+  MIDDLE_REGS,
+  HIGH_REGS,
+  GENERAL_REGS,
+  FRAME_REGS,
+  ALL_REGS,
+  LIM_REG_CLASSES
+};
+
+#define N_REG_CLASSES (int) LIM_REG_CLASSES
+
+#define REG_CLASS_NAMES \
+{                       \
+  "NO_REGS",            \
+  "R15_TA_REG",         \
+  "STACK_REG",          \
+  "LOW_REGS",           \
+  "MIDDLE_REGS",        \
+  "HIGH_REGS",          \
+  "GENERAL_REGS",       \
+  "FRAME_REGS",         \
+  "ALL_REGS"            \
+}
+
+#define REG_CLASS_CONTENTS \
+{                                                            \
+  {0x00000000, 0x00000000}, /* NO_REGS     :              */ \
+  {0x00008000, 0x00000000}, /* R15_TA_REG  : 15           */ \
+  {0x80000000, 0x00000000}, /* STACK_REG   : 31           */ \
+  {0x000000ff, 0x00000000}, /* LOW_REGS    : 0-7          */ \
+  {0x000f0fff, 0x00000000}, /* MIDDLE_REGS : 0-11, 16-19  */ \
+  {0xfff07000, 0x00000000}, /* HIGH_REGS   : 12-14, 20-31 */ \
+  {0xffffffff, 0x00000000}, /* GENERAL_REGS: 0-31         */ \
+  {0x00000000, 0x00000003}, /* FRAME_REGS  : 32, 33       */ \
+  {0xffffffff, 0x00000003}  /* ALL_REGS    : 0-31, 32, 33 */ \
+}
+
+#define REGNO_REG_CLASS(regno) nds32_regno_reg_class (regno)
+
+#define BASE_REG_CLASS GENERAL_REGS
+#define INDEX_REG_CLASS GENERAL_REGS
+
+/* Return nonzero if it is suitable for use as a
+   base register in operand addresses.
+   So far, we return nonzero only if "num" is a hard reg
+   of the suitable class or a pseudo register which is
+   allocated to a suitable hard reg.  */
+#define REGNO_OK_FOR_BASE_P(num) \
+  ((num) < 32 || (unsigned) reg_renumber[num] < 32)
+
+/* Return nonzero if it is suitable for use as a
+   index register in operand addresses.
+   So far, we return nonzero only if "num" is a hard reg
+   of the suitable class or a pseudo register which is
+   allocated to a suitable hard reg.
+   The difference between an index register and a base register is that
+   the index register may be scaled.  */
+#define REGNO_OK_FOR_INDEX_P(num) \
+  ((num) < 32 || (unsigned) reg_renumber[num] < 32)
+
+
+/* Obsolete Macros for Defining Constraints.  */
+
+
+/* Stack Layout and Calling Conventions.  */
+
+#define STACK_GROWS_DOWNWARD
+
+#define FRAME_GROWS_DOWNWARD 1
+
+#define STARTING_FRAME_OFFSET 0
+
+#define STACK_POINTER_OFFSET 0
+
+#define FIRST_PARM_OFFSET(fundecl) 0
+
+#define RETURN_ADDR_RTX(count, frameaddr) \
+  nds32_return_addr_rtx (count, frameaddr)
+
+/* A C expression whose value is RTL representing the location
+   of the incoming return address at the beginning of any function
+   before the prologue.
+   If this RTL is REG, you should also define
+   DWARF_FRAME_RETURN_COLUMN to DWARF_FRAME_REGNUM (REGNO).  */
+#define INCOMING_RETURN_ADDR_RTX    gen_rtx_REG (Pmode, LP_REGNUM)
+#define DWARF_FRAME_RETURN_COLUMN   DWARF_FRAME_REGNUM (LP_REGNUM)
+
+#define STACK_POINTER_REGNUM SP_REGNUM
+
+#define FRAME_POINTER_REGNUM 33
+
+#define HARD_FRAME_POINTER_REGNUM FP_REGNUM
+
+#define ARG_POINTER_REGNUM 32
+
+#define STATIC_CHAIN_REGNUM 16
+
+#define ELIMINABLE_REGS                                \
+{ { ARG_POINTER_REGNUM,   STACK_POINTER_REGNUM },      \
+  { ARG_POINTER_REGNUM,   HARD_FRAME_POINTER_REGNUM }, \
+  { FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM },      \
+  { FRAME_POINTER_REGNUM, HARD_FRAME_POINTER_REGNUM } }
+
+#define INITIAL_ELIMINATION_OFFSET(from_reg, to_reg, offset_var) \
+  (offset_var) = nds32_initial_elimination_offset (from_reg, to_reg)
+
+#define ACCUMULATE_OUTGOING_ARGS 1
+
+#define OUTGOING_REG_PARM_STACK_SPACE(fntype) 1
+
+#define CUMULATIVE_ARGS nds32_cumulative_args
+
+#define INIT_CUMULATIVE_ARGS(cum, fntype, libname, fndecl, n_named_args) \
+  nds32_init_cumulative_args (&cum, fntype, libname, fndecl, n_named_args)
+
+/* The REGNO is an unsigned integer but NDS32_GPR_ARG_FIRST_REGNUM may be 0.
+   We better cast REGNO into signed integer so that we can avoid
+   'comparison of unsigned expression >= 0 is always true' warning.  */
+#define FUNCTION_ARG_REGNO_P(regno)                                        \
+  (((int) regno - NDS32_GPR_ARG_FIRST_REGNUM >= 0)                         \
+   && ((int) regno - NDS32_GPR_ARG_FIRST_REGNUM < NDS32_MAX_REGS_FOR_ARGS))
+
+#define DEFAULT_PCC_STRUCT_RETURN 0
+
+/* EXIT_IGNORE_STACK should be nonzero if, when returning
+   from a function, the stack pointer does not matter.
+   The value is tested only in functions that have frame pointers.
+   In nds32 target, the function epilogue recovers the
+   stack pointer from the frame.  */
+#define EXIT_IGNORE_STACK 1
+
+#define FUNCTION_PROFILER(file, labelno) \
+  fprintf (file, "/* profiler %d */", (labelno))
+
+
+/* Implementing the Varargs Macros.  */
+
+
+/* Trampolines for Nested Functions.  */
+
+/* Giving A-function and B-function,
+   if B-function wants to call A-function's nested function,
+   we need to fill trampoline code into A-function's stack
+   so that B-function can execute the code in stack to indirectly
+   jump to (like 'trampoline' action) desired nested function.
+
+   The trampoline code for nds32 target must contains following parts:
+
+     1. instructions (4 * 4 = 16 bytes):
+          get $pc first
+          load chain_value to static chain register via $pc
+          load nested function address to $r15 via $pc
+          jump to desired nested function via $r15
+     2. data (4 * 2 = 8 bytes):
+          chain_value
+          nested function address
+
+   Please check nds32.c implementation for more information.  */
+#define TRAMPOLINE_SIZE 24
+
+/* Because all instructions/data in trampoline template are 4-byte size,
+   we set trampoline alignment 8*4=32 bits.  */
+#define TRAMPOLINE_ALIGNMENT 32
+
+
+/* Implicit Calls to Library Routines.  */
+
+
+/* Addressing Modes.  */
+
+/* We can use "LWI.bi  Rt, [Ra], 4" to support post increment.  */
+#define HAVE_POST_INCREMENT 1
+/* We can use "LWI.bi  Rt, [Ra], -4" to support post decrement.  */
+#define HAVE_POST_DECREMENT 1
+
+/* We have "LWI.bi  Rt, [Ra], imm" instruction form.  */
+#define HAVE_POST_MODIFY_DISP 1
+/* We have "LW.bi   Rt, [Ra], Rb" instruction form.  */
+#define HAVE_POST_MODIFY_REG  1
+
+#define CONSTANT_ADDRESS_P(x) (CONSTANT_P (x) && GET_CODE (x) != CONST_DOUBLE)
+
+#define MAX_REGS_PER_ADDRESS 2
+
+
+/* Anchored Addresses.  */
+
+
+/* Condition Code Status.  */
+
+
+/* Describing Relative Costs of Operations.  */
+
+/* A C expression for the cost of a branch instruction.
+   A value of 1 is the default;
+   other values are interpreted relative to that.  */
+#define BRANCH_COST(speed_p, predictable_p) ((speed_p) ? 2 : 0)
+
+#define SLOW_BYTE_ACCESS 1
+
+#define NO_FUNCTION_CSE
+
+
+/* Adjusting the Instruction Scheduler.  */
+
+
+/* Dividing the Output into Sections (Texts, Data, . . . ).  */
+
+#define TEXT_SECTION_ASM_OP     "\t.text"
+#define DATA_SECTION_ASM_OP     "\t.data"
+
+/* Currently, nds32 assembler does NOT handle '.bss' pseudo-op.
+   So we use '.section .bss' alternatively.  */
+#define BSS_SECTION_ASM_OP      "\t.section\t.bss"
+
+/* Define this macro to be an expression with a nonzero value if jump tables
+   (for tablejump insns) should be output in the text section,
+   along with the assembler instructions.
+   Otherwise, the readonly data section is used.  */
+#define JUMP_TABLES_IN_TEXT_SECTION 1
+
+
+/* Position Independent Code.  */
+
+
+/* Defining the Output Assembler Language.  */
+
+#define ASM_COMMENT_START "!"
+
+#define ASM_APP_ON "! #APP"
+
+#define ASM_APP_OFF "! #NO_APP\n"
+
+#define ASM_OUTPUT_LABELREF(stream, name) \
+  asm_fprintf (stream, "%U%s", (*targetm.strip_name_encoding) (name))
+
+#define ASM_OUTPUT_SYMBOL_REF(stream, sym) \
+  assemble_name (stream, XSTR (sym, 0))
+
+#define ASM_OUTPUT_LABEL_REF(stream, buf) \
+  assemble_name (stream, buf)
+
+#define LOCAL_LABEL_PREFIX "."
+
+#define REGISTER_NAMES                                            \
+{                                                                 \
+  "$r0",  "$r1",  "$r2",  "$r3",  "$r4",  "$r5",  "$r6",  "$r7",  \
+  "$r8",  "$r9",  "$r10", "$r11", "$r12", "$r13", "$r14", "$ta",  \
+  "$r16", "$r17", "$r18", "$r19", "$r20", "$r21", "$r22", "$r23", \
+  "$r24", "$r25", "$r26", "$r27", "$fp",  "$gp",  "$lp",  "$sp",  \
+  "$AP",                                                          \
+  "$SFP"                                                          \
+}
+
+/* Output normal jump table entry.  */
+#define ASM_OUTPUT_ADDR_VEC_ELT(stream, value) \
+  asm_fprintf (stream, "\t.word\t%LL%d\n", value)
+
+/* Output pc relative jump table entry.  */
+#define ASM_OUTPUT_ADDR_DIFF_ELT(stream, body, value, rel)              \
+  do                                                                    \
+    {                                                                   \
+      switch (GET_MODE (body))                                          \
+        {                                                               \
+        case QImode:                                                    \
+          asm_fprintf (stream, "\t.byte\t.L%d-.L%d\n", value, rel);     \
+          break;                                                        \
+        case HImode:                                                    \
+          asm_fprintf (stream, "\t.short\t.L%d-.L%d\n", value, rel);    \
+          break;                                                        \
+        case SImode:                                                    \
+          asm_fprintf (stream, "\t.word\t.L%d-.L%d\n", value, rel);     \
+          break;                                                        \
+        default:                                                        \
+          gcc_unreachable();                                            \
+        }                                                               \
+    } while (0)
+
+/* We have to undef it first because elfos.h formerly define it
+   check gcc/config.gcc and gcc/config/elfos.h for more information.  */
+#undef  ASM_OUTPUT_CASE_LABEL
+#define ASM_OUTPUT_CASE_LABEL(stream, prefix, num, table)          \
+  do                                                               \
+    {                                                              \
+      asm_fprintf (stream, "\t! Jump Table Begin\n");              \
+      (*targetm.asm_out.internal_label) (stream, prefix, num);     \
+    } while (0)
+
+#define ASM_OUTPUT_CASE_END(stream, num, table)        \
+  do                                                   \
+    {                                                  \
+      /* Because our jump table is in text section,    \
+         we need to make sure 2-byte alignment after   \
+         the jump table for instructions fetch.  */    \
+      if (GET_MODE (PATTERN (table)) == QImode)        \
+        ASM_OUTPUT_ALIGN (stream, 1);                  \
+      asm_fprintf (stream, "\t! Jump Table End\n");    \
+    }  while (0)
+
+/* This macro is not documented yet.
+   But we do need it to make jump table vector aligned.  */
+#define ADDR_VEC_ALIGN(JUMPTABLE) 2
+
+#define DWARF2_UNWIND_INFO 1
+
+#define JUMP_ALIGN(x) \
+  (align_jumps_log ? align_jumps_log : nds32_target_alignment (x))
+
+#define LOOP_ALIGN(x) \
+  (align_loops_log ? align_loops_log : nds32_target_alignment (x))
+
+#define LABEL_ALIGN(x) \
+  (align_labels_log ? align_labels_log : nds32_target_alignment (x))
+
+#define ASM_OUTPUT_ALIGN(stream, power) \
+  fprintf (stream, "\t.align\t%d\n", power)
+
+
+/* Controlling Debugging Information Format.  */
+
+#define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
+
+#define DWARF2_DEBUGGING_INFO 1
+
+#define DWARF2_ASM_LINE_DEBUG_INFO 1
+
+
+/* Cross Compilation and Floating Point.  */
+
+
+/* Mode Switching Instructions.  */
+
+
+/* Defining target-specific uses of __attribute__.  */
+
+
+/* Emulating TLS.  */
+
+
+/* Defining coprocessor specifics for MIPS targets.  */
+
+
+/* Parameters for Precompiled Header Validity Checking.  */
+
+
+/* C++ ABI parameters.  */
+
+
+/* Adding support for named address spaces.  */
+
+
+/* Miscellaneous Parameters.  */
+
+/* This is the machine mode that elements of a jump-table should have.  */
+#define CASE_VECTOR_MODE Pmode
+
+/* Return the preferred mode for and addr_diff_vec when the mininum
+   and maximum offset are known.  */
+#define CASE_VECTOR_SHORTEN_MODE(min_offset, max_offset, body)  \
+   ((min_offset < 0 || max_offset >= 0x2000 ) ? SImode          \
+   : (max_offset >= 100) ? HImode                               \
+   : QImode)
+
+/* Generate pc relative jump table when -fpic or -Os.  */
+#define CASE_VECTOR_PC_RELATIVE (flag_pic || optimize_size)
+
+/* Define this macro if operations between registers with integral mode
+   smaller than a word are always performed on the entire register.  */
+#define WORD_REGISTER_OPERATIONS
+
+/* A C expression indicating when insns that read memory in mem_mode,
+   an integral mode narrower than a word, set the bits outside of mem_mode
+   to be either the sign-extension or the zero-extension of the data read.  */
+#define LOAD_EXTEND_OP(MODE) ZERO_EXTEND
+
+/* The maximum number of bytes that a single instruction can move quickly
+   between memory and registers or between two memory locations.  */
+#define MOVE_MAX 4
+
+/* A C expression that is nonzero if on this machine the number of bits
+   actually used for the count of a shift operation is equal to the number
+   of bits needed to represent the size of the object being shifted.  */
+#define SHIFT_COUNT_TRUNCATED 1
+
+/* A C expression which is nonzero if on this machine it is safe to "convert"
+   an integer of 'inprec' bits to one of 'outprec' bits by merely operating
+   on it as if it had only 'outprec' bits.  */
+#define TRULY_NOOP_TRUNCATION(outprec, inprec) 1
+
+/* A C expression describing the value returned by a comparison operator with
+   an integral mode and stored by a store-flag instruction ('cstoremode4')
+   when the condition is true.  */
+#define STORE_FLAG_VALUE 1
+
+/* An alias for the machine mode for pointers.  */
+#define Pmode SImode
+
+/* An alias for the machine mode used for memory references to functions
+   being called, in call RTL expressions.  */
+#define FUNCTION_MODE SImode
+
+/* ------------------------------------------------------------------------ */
