target/i386: Set default NaN pattern explicitly

Set the default NaN pattern explicitly, and remove the ifdef from
parts64_default_nan().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241202131347.498124-38-peter.maydell@linaro.org

fpu/softfloat-specialize.c.inc

@@ -139,9 +139,6 @@ static void parts64_default_nan(FloatParts64 *p, float_status *status)
 #if defined(TARGET_SPARC) || defined(TARGET_M68K)
         /* Sign bit clear, all frac bits set */
         dnan_pattern = 0b01111111;
-#elif defined(TARGET_I386) || defined(TARGET_X86_64)
-        /* Sign bit set, most significant frac bit set */
-        dnan_pattern = 0b11000000;
 #elif defined(TARGET_HPPA)
         /* Sign bit clear, msb-1 frac bit set */
         dnan_pattern = 0b00100000;

target/i386/tcg/fpu_helper.c

@@ -181,6 +181,10 @@ void cpu_init_fp_statuses(CPUX86State *env)
      */
     set_float_infzeronan_rule(float_infzeronan_dnan_never, &env->sse_status);
     set_float_3nan_prop_rule(float_3nan_prop_abc, &env->sse_status);
+    /* Default NaN: sign bit set, most significant frac bit set */
+    set_float_default_nan_pattern(0b11000000, &env->fp_status);
+    set_float_default_nan_pattern(0b11000000, &env->mmx_status);
+    set_float_default_nan_pattern(0b11000000, &env->sse_status);
 }
 
 static inline uint8_t save_exception_flags(CPUX86State *env)