[v2,for-10.0,32/54] target/sparc: Initialize local scratch float_status from env->fp_status

Commit Message

Peter Maydell Dec. 2, 2024, 1:13 p.m. UTC

In the helper functions flcmps and flcmpd we use a scratch float_status
so that we don't change the CPU state if the comparison raises any
floating point exception flags. Instead of zero-initializing this
scratch float_status, initialize it as a copy of env->fp_status. This
avoids the need to explicitly initialize settings like the NaN
propagation rule or others we might add to softfloat in future.

To do this we need to pass the CPU env pointer in to the helper.

Signed-off-by: Peter Maydell <[e-mail]>
---
 target/sparc/helper.h     | 4 ++--
 target/sparc/fop_helper.c | 8 ++++----
 target/sparc/translate.c  | 4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

Comments

Richard Henderson Dec. 2, 2024, 5:24 p.m. UTC | #1

On 12/2/24 07:13, Peter Maydell wrote:
> In the helper functions flcmps and flcmpd we use a scratch float_status
> so that we don't change the CPU state if the comparison raises any
> floating point exception flags. Instead of zero-initializing this
> scratch float_status, initialize it as a copy of env->fp_status. This
> avoids the need to explicitly initialize settings like the NaN
> propagation rule or others we might add to softfloat in future.
> 
> To do this we need to pass the CPU env pointer in to the helper.
> 
> Signed-off-by: Peter Maydell<[e-mail]>
> ---
>   target/sparc/helper.h     | 4 ++--
>   target/sparc/fop_helper.c | 8 ++++----
>   target/sparc/translate.c  | 4 ++--
>   3 files changed, 8 insertions(+), 8 deletions(-)

Reviewed-by: Richard Henderson <[e-mail]>

r~

Patch

diff --git a/target/sparc/helper.h b/target/sparc/helper.h
index 134e519a377..1ae3f0c467d 100644
--- a/target/sparc/helper.h
+++ b/target/sparc/helper.h
@@ -51,8 +51,8 @@  DEF_HELPER_FLAGS_3(fcmpd, TCG_CALL_NO_WG, i32, env, f64, f64)
 DEF_HELPER_FLAGS_3(fcmped, TCG_CALL_NO_WG, i32, env, f64, f64)
 DEF_HELPER_FLAGS_3(fcmpq, TCG_CALL_NO_WG, i32, env, i128, i128)
 DEF_HELPER_FLAGS_3(fcmpeq, TCG_CALL_NO_WG, i32, env, i128, i128)
-DEF_HELPER_FLAGS_2(flcmps, TCG_CALL_NO_RWG_SE, i32, f32, f32)
-DEF_HELPER_FLAGS_2(flcmpd, TCG_CALL_NO_RWG_SE, i32, f64, f64)
+DEF_HELPER_FLAGS_3(flcmps, TCG_CALL_NO_RWG_SE, i32, env, f32, f32)
+DEF_HELPER_FLAGS_3(flcmpd, TCG_CALL_NO_RWG_SE, i32, env, f64, f64)
 DEF_HELPER_2(raise_exception, noreturn, env, int)
 
 DEF_HELPER_FLAGS_3(faddd, TCG_CALL_NO_WG, f64, env, f64, f64)
diff --git a/target/sparc/fop_helper.c b/target/sparc/fop_helper.c
index 6f9ccc008a0..236d27b19c1 100644
--- a/target/sparc/fop_helper.c
+++ b/target/sparc/fop_helper.c
@@ -490,13 +490,13 @@  uint32_t helper_fcmpeq(CPUSPARCState *env, Int128 src1, Int128 src2)
     return finish_fcmp(env, r, GETPC());
 }
 
-uint32_t helper_flcmps(float32 src1, float32 src2)
+uint32_t helper_flcmps(CPUSPARCState *env, float32 src1, float32 src2)
 {
     /*
      * FLCMP never raises an exception nor modifies any FSR fields.
      * Perform the comparison with a dummy fp environment.
      */
-    float_status discard = { };
+    float_status discard = env->fp_status;
     FloatRelation r;
 
     set_float_2nan_prop_rule(float_2nan_prop_s_ba, &discard);
@@ -518,9 +518,9 @@  uint32_t helper_flcmps(float32 src1, float32 src2)
     g_assert_not_reached();
 }
 
-uint32_t helper_flcmpd(float64 src1, float64 src2)
+uint32_t helper_flcmpd(CPUSPARCState *env, float64 src1, float64 src2)
 {
-    float_status discard = { };
+    float_status discard = env->fp_status;
     FloatRelation r;
 
     set_float_2nan_prop_rule(float_2nan_prop_s_ba, &discard);
diff --git a/target/sparc/translate.c b/target/sparc/translate.c
index cdd0a95c03d..322319a1288 100644
--- a/target/sparc/translate.c
+++ b/target/sparc/translate.c
@@ -5584,7 +5584,7 @@  static bool trans_FLCMPs(DisasContext *dc, arg_FLCMPs *a)
 
     src1 = gen_load_fpr_F(dc, a->rs1);
     src2 = gen_load_fpr_F(dc, a->rs2);
-    gen_helper_flcmps(cpu_fcc[a->cc], src1, src2);
+    gen_helper_flcmps(cpu_fcc[a->cc], tcg_env, src1, src2);
     return advance_pc(dc);
 }
 
@@ -5601,7 +5601,7 @@  static bool trans_FLCMPd(DisasContext *dc, arg_FLCMPd *a)
 
     src1 = gen_load_fpr_D(dc, a->rs1);
     src2 = gen_load_fpr_D(dc, a->rs2);
-    gen_helper_flcmpd(cpu_fcc[a->cc], src1, src2);
+    gen_helper_flcmpd(cpu_fcc[a->cc], tcg_env, src1, src2);
     return advance_pc(dc);
 }