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[v5,2/2] target/riscv: change the api for RVF/RVD fmin/fmax

Message ID 20211021160847.2748577-3-frank.chang@sifive.com
State New
Headers show
Series [v5,1/2] softfloat: add APIs to handle alternative sNaN propagation for fmax/fmin | expand

Commit Message

Frank Chang Oct. 21, 2021, 4:08 p.m. UTC 
From: Chih-Min Chao <chihmin.chao@sifive.com>

The sNaN propagation behavior has been changed since cd20cee7 in
https://github.com/riscv/riscv-isa-manual.

In Priv spec v1.10, RVF is v2.0. fmin.s and fmax.s are implemented with
IEEE 754-2008 minNum and maxNum operations.

In Priv spec v1.11, RVF is v2.2. fmin.s and fmax.s are amended to
implement IEEE 754-2019 minimumNumber and maximumNumber operations.

Therefore, to prevent the risk of having too many version variables.
Instead of introducing an extra *fext_ver* variable, we tie RVF version
to Priv version. Though it's not completely accurate but is close enough.

Signed-off-by: Chih-Min Chao <chihmin.chao@sifive.com>
Signed-off-by: Frank Chang <frank.chang@sifive.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/fpu_helper.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)
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Patch

diff --git a/target/riscv/fpu_helper.c b/target/riscv/fpu_helper.c
index 8700516a14c..d62f4709002 100644
--- a/target/riscv/fpu_helper.c
+++ b/target/riscv/fpu_helper.c
@@ -174,14 +174,18 @@  uint64_t helper_fmin_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
 {
     float32 frs1 = check_nanbox_s(rs1);
     float32 frs2 = check_nanbox_s(rs2);
-    return nanbox_s(float32_minnum(frs1, frs2, &env->fp_status));
+    return nanbox_s(env->priv_ver < PRIV_VERSION_1_11_0 ?
+                    float32_minnum(frs1, frs2, &env->fp_status) :
+                    float32_minimum_number(frs1, frs2, &env->fp_status));
 }
 
 uint64_t helper_fmax_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
 {
     float32 frs1 = check_nanbox_s(rs1);
     float32 frs2 = check_nanbox_s(rs2);
-    return nanbox_s(float32_maxnum(frs1, frs2, &env->fp_status));
+    return nanbox_s(env->priv_ver < PRIV_VERSION_1_11_0 ?
+                    float32_maxnum(frs1, frs2, &env->fp_status) :
+                    float32_maximum_number(frs1, frs2, &env->fp_status));
 }
 
 uint64_t helper_fsqrt_s(CPURISCVState *env, uint64_t rs1)
@@ -283,12 +287,16 @@  uint64_t helper_fdiv_d(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
 
 uint64_t helper_fmin_d(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
 {
-    return float64_minnum(frs1, frs2, &env->fp_status);
+    return env->priv_ver < PRIV_VERSION_1_11_0 ?
+            float64_minnum(frs1, frs2, &env->fp_status) :
+            float64_minimum_number(frs1, frs2, &env->fp_status);
 }
 
 uint64_t helper_fmax_d(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
 {
-    return float64_maxnum(frs1, frs2, &env->fp_status);
+    return env->priv_ver < PRIV_VERSION_1_11_0 ?
+            float64_maxnum(frs1, frs2, &env->fp_status) :
+            float64_maximum_number(frs1, frs2, &env->fp_status);
 }
 
 uint64_t helper_fcvt_s_d(CPURISCVState *env, uint64_t rs1)