target/m68k: Init local float_status from env fp_status in gdb get/set reg

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>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241202131347.498124-32-peter.maydell@linaro.org

diff --git a/target/m68k/helper.c b/target/m68k/helper.c
index 9bfc6ae97c0ceb335fdadda708efde10bed07526..beefeb7069c91b8ea67de77057704006235534b4 100644 (file)
--- 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;
     }