The original code used "magic numbers", which made it unclear in
some places. Include a reference to the Intel manual where the
constants' meaning is discussed.
Signed-off-by: Jan Bobek <jan.bo...@gmail.com>
---
risu_reginfo_i386.c | 48 +++++++++++++++++++++++++++++++--------------
1 file changed, 33 insertions(+), 15 deletions(-)
diff --git a/risu_reginfo_i386.c b/risu_reginfo_i386.c
index 35ff7c8..aba5ae3 100644
--- a/risu_reginfo_i386.c
+++ b/risu_reginfo_i386.c
@@ -22,7 +22,25 @@
#include <asm/sigcontext.h>
-static uint64_t xfeatures = 3; /* SSE */
+/*
+ * Refer to "Intel(R) 64 and IA-32 Architectures Software Developer's
+ * Manual", Volume 1, Section 13.1 "XSAVE-Supported Features and
+ * State-Component Bitmaps" for detailed discussion of these constants
+ * and their meaning.
+ */
+enum {
+ XFEAT_X87 = 1 << 0,
+ XFEAT_SSE = 1 << 1,
+ XFEAT_AVX = 1 << 2,
+ XFEAT_AVX512_OPMASK = 1 << 5,
+ XFEAT_AVX512_ZMM_HI256 = 1 << 6,
+ XFEAT_AVX512_HI16_ZMM = 1 << 7,
+ XFEAT_AVX512 = XFEAT_AVX512_OPMASK
+ | XFEAT_AVX512_ZMM_HI256
+ | XFEAT_AVX512_HI16_ZMM
+};
+
+static uint64_t xfeatures = XFEAT_X87 | XFEAT_SSE;
static const struct option extra_ops[] = {
{"xfeatures", required_argument, NULL, FIRST_ARCH_OPT },
@@ -160,34 +178,34 @@ void reginfo_init(struct reginfo *ri, ucontext_t *uc)
* Now we know that _fpstate contains XSAVE data.
*/
- if (features & (1 << 2)) {
+ if (features & XFEAT_AVX) {
/* YMM_Hi128 state */
- void *buf = xsave_feature_buf(xs, 2);
+ void *buf = xsave_feature_buf(xs, XFEAT_AVX);
for (i = 0; i < nvecregs; ++i) {
memcpy(&ri->vregs[i].q[2], buf + 16 * i, 16);
}
}
- if (features & (1 << 5)) {
+ if (features & XFEAT_AVX512_OPMASK) {
/* Opmask state */
- uint64_t *buf = xsave_feature_buf(xs, 5);
+ uint64_t *buf = xsave_feature_buf(xs, XFEAT_AVX512_OPMASK);
for (i = 0; i < 8; ++i) {
ri->kregs[i] = buf[i];
}
}
- if (features & (1 << 6)) {
+ if (features & XFEAT_AVX512_ZMM_HI256) {
/* ZMM_Hi256 state */
- void *buf = xsave_feature_buf(xs, 6);
+ void *buf = xsave_feature_buf(xs, XFEAT_AVX512_ZMM_HI256);
for (i = 0; i < nvecregs; ++i) {
memcpy(&ri->vregs[i].q[4], buf + 32 * i, 32);
}
}
#ifdef __x86_64__
- if (features & (1 << 7)) {
+ if (features & XFEAT_AVX512_HI16_ZMM) {
/* Hi16_ZMM state */
- void *buf = xsave_feature_buf(xs, 7);
+ void *buf = xsave_feature_buf(xs, XFEAT_AVX512_HI16_ZMM);
for (i = 0; i < 16; ++i) {
memcpy(&ri->vregs[i + 16], buf + 64 * i, 64);
}
@@ -243,7 +261,7 @@ static const char *const regname[NGREG] = {
static int get_nvecregs(uint64_t features)
{
#ifdef __x86_64__
- return features & (1 << 7) ? 32 : 16;
+ return features & XFEAT_AVX512_HI16_ZMM ? 32 : 16;
#else
return 8;
#endif
@@ -251,9 +269,9 @@ static int get_nvecregs(uint64_t features)
static int get_nvecquads(uint64_t features)
{
- if (features & (1 << 6)) {
+ if (features & XFEAT_AVX512_ZMM_HI256) {
return 8;
- } else if (features & (1 << 2)) {
+ } else if (features & XFEAT_AVX) {
return 4;
} else {
return 2;
@@ -262,9 +280,9 @@ static int get_nvecquads(uint64_t features)
static char get_vecletter(uint64_t features)
{
- if (features & (1 << 6 | 1 << 7)) {
+ if (features & (XFEAT_AVX512_ZMM_HI256 | XFEAT_AVX512_HI16_ZMM)) {
return 'z';
- } else if (features & (1 << 2)) {
+ } else if (features & XFEAT_AVX) {
return 'y';
} else {
return 'x';
@@ -301,7 +319,7 @@ int reginfo_dump(struct reginfo *ri, FILE *f)
}
}
- if (features & (1 << 5)) {
+ if (features & XFEAT_AVX512_OPMASK) {
for (i = 0; i < 8; i++) {
fprintf(f, " k%-5d: %016" PRIx64 "\n", i, ri->kregs[i]);
}
--
2.20.1
