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[PATCH 3/5] target/i386: fix fscale handling of invalid exponent encodin
From: |
Joseph Myers |
Subject: |
[PATCH 3/5] target/i386: fix fscale handling of invalid exponent encodings |
Date: |
Thu, 7 May 2020 00:44:57 +0000 |
User-agent: |
Alpine 2.21 (DEB 202 2017-01-01) |
The fscale implementation does not check for invalid encodings in the
exponent operand, thus treating them like INT_MIN (the value returned
for invalid encodings by floatx80_to_int32_round_to_zero). Fix it to
treat them similarly to signaling NaN exponents, thus generating a
quiet NaN result.
Signed-off-by: Joseph Myers <address@hidden>
---
target/i386/fpu_helper.c | 5 ++++-
tests/tcg/i386/test-i386-fscale.c | 29 +++++++++++++++++++++++++++++
2 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/target/i386/fpu_helper.c b/target/i386/fpu_helper.c
index 60012c405c..7709af8fdd 100644
--- a/target/i386/fpu_helper.c
+++ b/target/i386/fpu_helper.c
@@ -968,7 +968,10 @@ void helper_frndint(CPUX86State *env)
void helper_fscale(CPUX86State *env)
{
- if (floatx80_is_any_nan(ST1)) {
+ if (floatx80_invalid_encoding(ST1)) {
+ float_raise(float_flag_invalid, &env->fp_status);
+ ST0 = floatx80_default_nan(&env->fp_status);
+ } else if (floatx80_is_any_nan(ST1)) {
ST0 = ST1;
if (floatx80_is_signaling_nan(ST0, &env->fp_status)) {
float_raise(float_flag_invalid, &env->fp_status);
diff --git a/tests/tcg/i386/test-i386-fscale.c
b/tests/tcg/i386/test-i386-fscale.c
index aecac5125f..b65a055d0a 100644
--- a/tests/tcg/i386/test-i386-fscale.c
+++ b/tests/tcg/i386/test-i386-fscale.c
@@ -8,6 +8,11 @@ union u {
long double ld;
};
+volatile union u ld_invalid_1 = { .s = { 1, 1234 } };
+volatile union u ld_invalid_2 = { .s = { 0, 1234 } };
+volatile union u ld_invalid_3 = { .s = { 0, 0x7fff } };
+volatile union u ld_invalid_4 = { .s = { (UINT64_C(1) << 63) - 1, 0x7fff } };
+
volatile long double ld_res;
int isnan_ld(long double x)
@@ -33,5 +38,29 @@ int main(void)
printf("FAIL: fscale snan\n");
ret = 1;
}
+ __asm__ volatile ("fscale" : "=t" (ld_res) :
+ "0" (2.5L), "u" (ld_invalid_1.ld));
+ if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
+ printf("FAIL: fscale invalid 1\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fscale" : "=t" (ld_res) :
+ "0" (2.5L), "u" (ld_invalid_2.ld));
+ if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
+ printf("FAIL: fscale invalid 2\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fscale" : "=t" (ld_res) :
+ "0" (2.5L), "u" (ld_invalid_3.ld));
+ if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
+ printf("FAIL: fscale invalid 3\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fscale" : "=t" (ld_res) :
+ "0" (2.5L), "u" (ld_invalid_4.ld));
+ if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
+ printf("FAIL: fscale invalid 4\n");
+ ret = 1;
+ }
return ret;
}
--
2.17.1
--
Joseph S. Myers
address@hidden
- [PATCH 0/5] target/i386: fxtract, fscale fixes, Joseph Myers, 2020/05/06
- [PATCH 1/5] target/i386: implement special cases for fxtract, Joseph Myers, 2020/05/06
- [PATCH 2/5] target/i386: fix fscale handling of signaling NaN, Joseph Myers, 2020/05/06
- [PATCH 3/5] target/i386: fix fscale handling of invalid exponent encodings,
Joseph Myers <=
- [PATCH 4/5] target/i386: fix fscale handling of infinite exponents, Joseph Myers, 2020/05/06
- [PATCH 5/5] target/i386: fix fscale handling of rounding precision, Joseph Myers, 2020/05/06
- Re: [PATCH 0/5] target/i386: fxtract, fscale fixes, no-reply, 2020/05/06
- Ping Re: [PATCH 0/5] target/i386: fxtract, fscale fixes, Joseph Myers, 2020/05/14
- Re: [PATCH 0/5] target/i386: fxtract, fscale fixes, Philippe Mathieu-Daudé, 2020/05/15
- Re: [PATCH 0/5] target/i386: fxtract, fscale fixes, Paolo Bonzini, 2020/05/21