[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH 2/4] target/i386: fix fxam handling of invalid encodings
|
From: |
Joseph Myers |
|
Subject: |
[PATCH 2/4] target/i386: fix fxam handling of invalid encodings |
|
Date: |
Wed, 13 May 2020 23:50:19 +0000 |
|
User-agent: |
Alpine 2.21 (DEB 202 2017-01-01) |
The fxam implementation does not check for invalid encodings, instead
treating them like NaN or normal numbers depending on the exponent.
Fix it to check that the high bit of the significand is set before
treating an encoding as NaN or normal, thus resulting in correct
handling (all of C0, C2 and C3 cleared) for invalid encodings.
Signed-off-by: Joseph Myers <address@hidden>
---
target/i386/fpu_helper.c | 4 +-
tests/tcg/i386/test-i386-fxam.c | 143 ++++++++++++++++++++++++++++++++
2 files changed, 145 insertions(+), 2 deletions(-)
create mode 100644 tests/tcg/i386/test-i386-fxam.c
diff --git a/target/i386/fpu_helper.c b/target/i386/fpu_helper.c
index 38968b2ec7..51372c371b 100644
--- a/target/i386/fpu_helper.c
+++ b/target/i386/fpu_helper.c
@@ -1099,7 +1099,7 @@ void helper_fxam_ST0(CPUX86State *env)
if (expdif == MAXEXPD) {
if (MANTD(temp) == 0x8000000000000000ULL) {
env->fpus |= 0x500; /* Infinity */
- } else {
+ } else if (MANTD(temp) & 0x8000000000000000ULL) {
env->fpus |= 0x100; /* NaN */
}
} else if (expdif == 0) {
@@ -1108,7 +1108,7 @@ void helper_fxam_ST0(CPUX86State *env)
} else {
env->fpus |= 0x4400; /* Denormal */
}
- } else {
+ } else if (MANTD(temp) & 0x8000000000000000ULL) {
env->fpus |= 0x400;
}
}
diff --git a/tests/tcg/i386/test-i386-fxam.c b/tests/tcg/i386/test-i386-fxam.c
new file mode 100644
index 0000000000..ddd76ca42d
--- /dev/null
+++ b/tests/tcg/i386/test-i386-fxam.c
@@ -0,0 +1,143 @@
+/* Test fxam instruction. */
+
+#include <stdint.h>
+#include <stdio.h>
+
+union u {
+ struct { uint64_t sig; uint16_t sign_exp; } s;
+ long double ld;
+};
+
+volatile union u ld_pseudo_m16382 = { .s = { UINT64_C(1) << 63, 0 } };
+volatile union u ld_pseudo_nm16382 = { .s = { UINT64_C(1) << 63, 0x8000 } };
+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 union u ld_invalid_n1 = { .s = { 1, 0x8123 } };
+volatile union u ld_invalid_n2 = { .s = { 0, 0x8123 } };
+volatile union u ld_invalid_n3 = { .s = { 0, 0xffff } };
+volatile union u ld_invalid_n4 = { .s = { (UINT64_C(1) << 63) - 1, 0xffff } };
+
+#define C0 (1 << 8)
+#define C1 (1 << 9)
+#define C2 (1 << 10)
+#define C3 (1 << 14)
+#define FLAGS (C0 | C1 | C2 | C3)
+
+int main(void)
+{
+ short sw;
+ int ret = 0;
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (0.0L));
+ if ((sw & FLAGS) != C3) {
+ printf("FAIL: +0\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (-0.0L));
+ if ((sw & FLAGS) != (C3 | C1)) {
+ printf("FAIL: -0\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (1.0L));
+ if ((sw & FLAGS) != C2) {
+ printf("FAIL: +normal\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (-1.0L));
+ if ((sw & FLAGS) != (C2 | C1)) {
+ printf("FAIL: -normal\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (__builtin_infl()));
+ if ((sw & FLAGS) != (C2 | C0)) {
+ printf("FAIL: +inf\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (-__builtin_infl()));
+ if ((sw & FLAGS) != (C2 | C1 | C0)) {
+ printf("FAIL: -inf\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (__builtin_nanl("")));
+ if ((sw & FLAGS) != C0) {
+ printf("FAIL: +nan\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (-__builtin_nanl("")));
+ if ((sw & FLAGS) != (C1 | C0)) {
+ printf("FAIL: -nan\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (__builtin_nansl("")));
+ if ((sw & FLAGS) != C0) {
+ printf("FAIL: +snan\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (-__builtin_nansl("")));
+ if ((sw & FLAGS) != (C1 | C0)) {
+ printf("FAIL: -snan\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (0x1p-16445L));
+ if ((sw & FLAGS) != (C3 | C2)) {
+ printf("FAIL: +denormal\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (-0x1p-16445L));
+ if ((sw & FLAGS) != (C3 | C2 | C1)) {
+ printf("FAIL: -denormal\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_pseudo_m16382.ld));
+ if ((sw & FLAGS) != (C3 | C2)) {
+ printf("FAIL: +pseudo-denormal\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_pseudo_nm16382.ld));
+ if ((sw & FLAGS) != (C3 | C2 | C1)) {
+ printf("FAIL: -pseudo-denormal\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_invalid_1.ld));
+ if ((sw & FLAGS) != 0) {
+ printf("FAIL: +invalid 1\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_invalid_n1.ld));
+ if ((sw & FLAGS) != C1) {
+ printf("FAIL: -invalid 1\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_invalid_2.ld));
+ if ((sw & FLAGS) != 0) {
+ printf("FAIL: +invalid 2\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_invalid_n2.ld));
+ if ((sw & FLAGS) != C1) {
+ printf("FAIL: -invalid 2\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_invalid_3.ld));
+ if ((sw & FLAGS) != 0) {
+ printf("FAIL: +invalid 3\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_invalid_n3.ld));
+ if ((sw & FLAGS) != C1) {
+ printf("FAIL: -invalid 3\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_invalid_4.ld));
+ if ((sw & FLAGS) != 0) {
+ printf("FAIL: +invalid 4\n");
+ ret = 1;
+ }
+ __asm__ volatile ("fxam\nfnstsw" : "=a" (sw) : "t" (ld_invalid_n4.ld));
+ if ((sw & FLAGS) != C1) {
+ printf("FAIL: -invalid 4\n");
+ ret = 1;
+ }
+ return ret;
+}
--
2.17.1
--
Joseph S. Myers
address@hidden