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[v2,for-10.0,31/54] target/m68k: Init local float_status from env fp_status in gdb get/set reg

Message ID 20241202131347.498124-32-peter.maydell@linaro.org
State Superseded
Headers show
Series fpu: Remove pickNaNMulAdd, default-NaN ifdefs | expand

Commit Message

Peter Maydell Dec. 2, 2024, 1:13 p.m. UTC 
In cf_fpu_gdb_get_reg() and cf_fpu_gdb_set_reg() we do the conversion
from float64 to floatx80 using a scratch float_status, because we
don't want the conversion to affect the CPU's floating point exception
status. Currently we use a zero-initialized float_status. This will
get steadily more awkward as we add config knobs to float_status
that the target must initialize. Avoid having to add any of that
configuration here by instead initializing our local float_status
from the env->fp_status.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/m68k/helper.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Richard Henderson Dec. 2, 2024, 5:23 p.m. UTC | #1 
On 12/2/24 07:13, Peter Maydell wrote:
> In cf_fpu_gdb_get_reg() and cf_fpu_gdb_set_reg() we do the conversion
> from float64 to floatx80 using a scratch float_status, because we
> don't want the conversion to affect the CPU's floating point exception
> status. Currently we use a zero-initialized float_status. This will
> get steadily more awkward as we add config knobs to float_status
> that the target must initialize. Avoid having to add any of that
> configuration here by instead initializing our local float_status
> from the env->fp_status.
> 
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
>   target/m68k/helper.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)

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

r~
diff mbox series

Patch

diff --git a/target/m68k/helper.c b/target/m68k/helper.c
index 9bfc6ae97c0..beefeb7069c 100644
--- a/target/m68k/helper.c
+++ b/target/m68k/helper.c
@@ -36,7 +36,8 @@  static int cf_fpu_gdb_get_reg(CPUState *cs, GByteArray *mem_buf, int n)
     CPUM68KState *env = &cpu->env;
 
     if (n < 8) {
-        float_status s = {};
+        /* Use scratch float_status so any exceptions don't change CPU state */
+        float_status s = env->fp_status;
         return gdb_get_reg64(mem_buf, floatx80_to_float64(env->fregs[n].d, &s));
     }
     switch (n) {
@@ -56,7 +57,8 @@  static int cf_fpu_gdb_set_reg(CPUState *cs, uint8_t *mem_buf, int n)
     CPUM68KState *env = &cpu->env;
 
     if (n < 8) {
-        float_status s = {};
+        /* Use scratch float_status so any exceptions don't change CPU state */
+        float_status s = env->fp_status;
         env->fregs[n].d = float64_to_floatx80(ldq_be_p(mem_buf), &s);
         return 8;
     }