target-i386: Wrong conversion infinity from float80 to int32/int64

Signed-off-by: NDmitry Poletaev <poletaev-qemu@yandex.ru>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

target-i386/fpu_helper.c

@@ -251,16 +251,34 @@ int32_t helper_fist_ST0(CPUX86State *env)
 int32_t helper_fistl_ST0(CPUX86State *env)
 {
     int32_t val;
+    signed char old_exp_flags;
+
+    old_exp_flags = get_float_exception_flags(&env->fp_status);
+    set_float_exception_flags(0, &env->fp_status);
 
     val = floatx80_to_int32(ST0, &env->fp_status);
+    if (get_float_exception_flags(&env->fp_status) & float_flag_invalid) {
+        val = 0x80000000;
+    }
+    set_float_exception_flags(get_float_exception_flags(&env->fp_status)
+                                | old_exp_flags, &env->fp_status);
     return val;
 }
 
 int64_t helper_fistll_ST0(CPUX86State *env)
 {
     int64_t val;
+    signed char old_exp_flags;
 
-    val = floatx80_to_int64(ST0, &env->fp_status);
+    old_exp_flags = get_float_exception_flags(&env->fp_status);
+    set_float_exception_flags(0, &env->fp_status);
+
+    val = floatx80_to_int32(ST0, &env->fp_status);
+    if (get_float_exception_flags(&env->fp_status) & float_flag_invalid) {
+        val = 0x8000000000000000ULL;
+    }
+    set_float_exception_flags(get_float_exception_flags(&env->fp_status)
+                                | old_exp_flags, &env->fp_status);
     return val;
 }