diff mbox series

[v2,3/7] target/ppc: reduce usage of fpscr_set_rounding_mode

Message ID 20210518150515.57983-4-bruno.larsen@eldorado.org.br
State New
Headers show
Series target/ppc: Misc motion to support disabling TCG | expand

Commit Message

Bruno Larsen (billionai) May 18, 2021, 3:05 p.m. UTC 
It is preferable to store the current rounding mode and restore from that
than recalculating from fpscr, so we changed the behavior of do_fri and
VSX_ROUND to do it like that.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Bruno Larsen (billionai) <bruno.larsen@eldorado.org.br>
---
 target/ppc/fpu_helper.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Comments

Richard Henderson May 19, 2021, 3:56 p.m. UTC | #1 
On 5/18/21 10:05 AM, Bruno Larsen (billionai) wrote:
> +    int old_rounding_mode = get_float_rounding_mode(&env->fp_status);

FloatRoundMode is a better type for the variable.

> @@ -3136,8 +3136,10 @@ void helper_##op(CPUPPCState *env, ppc_vsr_t *xt, ppc_vsr_t *xb)       \
>  {                                                                      \
>      ppc_vsr_t t = *xt;                                                 \
>      int i;                                                             \
> +    int curr_rounding_mode;                                            \

Likewise.  Otherwise,

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
diff mbox series

Patch

diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index 44315fca0b..4799d5f5e4 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -822,6 +822,7 @@  static inline uint64_t do_fri(CPUPPCState *env, uint64_t arg,
                               int rounding_mode)
 {
     CPU_DoubleU farg;
+    int old_rounding_mode = get_float_rounding_mode(&env->fp_status);
 
     farg.ll = arg;
 
@@ -834,8 +835,7 @@  static inline uint64_t do_fri(CPUPPCState *env, uint64_t arg,
                       float_flag_inexact;
         set_float_rounding_mode(rounding_mode, &env->fp_status);
         farg.ll = float64_round_to_int(farg.d, &env->fp_status);
-        /* Restore rounding mode from FPSCR */
-        fpscr_set_rounding_mode(env);
+        set_float_rounding_mode(old_rounding_mode, &env->fp_status);
 
         /* fri* does not set FPSCR[XX] */
         if (!inexact) {
@@ -3136,8 +3136,10 @@  void helper_##op(CPUPPCState *env, ppc_vsr_t *xt, ppc_vsr_t *xb)       \
 {                                                                      \
     ppc_vsr_t t = *xt;                                                 \
     int i;                                                             \
+    int curr_rounding_mode;                                            \
                                                                        \
     if (rmode != FLOAT_ROUND_CURRENT) {                                \
+        curr_rounding_mode = get_float_rounding_mode(&env->fp_status); \
         set_float_rounding_mode(rmode, &env->fp_status);               \
     }                                                                  \
                                                                        \
@@ -3160,7 +3162,7 @@  void helper_##op(CPUPPCState *env, ppc_vsr_t *xt, ppc_vsr_t *xb)       \
      * mode from FPSCR                                                 \
      */                                                                \
     if (rmode != FLOAT_ROUND_CURRENT) {                                \
-        fpscr_set_rounding_mode(env);                                  \
+        set_float_rounding_mode(curr_rounding_mode, &env->fp_status);  \
         env->fp_status.float_exception_flags &= ~float_flag_inexact;   \
     }                                                                  \
                                                                        \