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fix AVX & AVX2 detection

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fixes issue #790 which resulted in a SIGILL on OpenBSD

code is mostly from libwebp, based on the following:

https://software.intel.com/en-us/articles/how-to-detect-new-instruction-support-in-the-4th-generation-intel-core-processor-family

Change-Id: Ida7c1a18261e98c05ed9c662068140be407ec107
This commit is contained in:
James Zern 2015-01-14 22:51:49 -08:00
parent 4e04fa6dea
commit 7e515c4637
1 changed files with 41 additions and 6 deletions
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47
vpx_ports/x86.h
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@ -13,6 +13,7 @@
#define VPX_PORTS_X86_H_
#include <stdlib.h>
#include "vpx_config.h"
#include "vpx/vpx_integer.h"
#ifdef __cplusplus
extern "C" {
@ -104,6 +105,37 @@ void __cpuid(int CPUInfo[4], int info_type);
#endif
#endif /* end others */
// NaCl has no support for xgetbv or the raw opcode.
#if !defined(__native_client__) && (defined(__i386__) || defined(__x86_64__))
static INLINE uint64_t xgetbv(void) {
const uint32_t ecx = 0;
uint32_t eax, edx;
// Use the raw opcode for xgetbv for compatibility with older toolchains.
__asm__ volatile (
".byte 0x0f, 0x01, 0xd0\n"
: "=a"(eax), "=d"(edx) : "c" (ecx));
return ((uint64_t)edx << 32) | eax;
}
#elif (defined(_M_X64) || defined(_M_IX86)) && \
defined(_MSC_FULL_VER) && _MSC_FULL_VER >= 160040219 // >= VS2010 SP1
#include <immintrin.h>
#define xgetbv() _xgetbv(0)
#elif defined(_MSC_VER) && defined(_M_IX86)
static INLINE uint64_t xgetbv(void) {
uint32_t eax_, edx_;
__asm {
xor ecx, ecx // ecx = 0
// Use the raw opcode for xgetbv for compatibility with older toolchains.
__asm _emit 0x0f __asm _emit 0x01 __asm _emit 0xd0
mov eax_, eax
mov edx_, edx
}
return ((uint64_t)edx_ << 32) | eax_;
}
#else
#define xgetbv() 0U // no AVX for older x64 or unrecognized toolchains.
#endif
#define HAS_MMX 0x01
#define HAS_SSE 0x02
#define HAS_SSE2 0x04
@ -156,14 +188,17 @@ x86_simd_caps(void) {
if (reg_ecx & BIT(19)) flags |= HAS_SSE4_1;
if (reg_ecx & BIT(28)) flags |= HAS_AVX;
// bits 27 (OSXSAVE) & 28 (256-bit AVX)
if (reg_ecx & (BIT(27) | BIT(28))) {
if ((xgetbv() & 0x6) == 0x6) {
flags |= HAS_AVX;
/* Get the leaf 7 feature flags. Needed to check for AVX2 support */
reg_eax = 7;
reg_ecx = 0;
cpuid(7, 0, reg_eax, reg_ebx, reg_ecx, reg_edx);
/* Get the leaf 7 feature flags. Needed to check for AVX2 support */
cpuid(7, 0, reg_eax, reg_ebx, reg_ecx, reg_edx);
if (reg_ebx & BIT(5)) flags |= HAS_AVX2;
if (reg_ebx & BIT(5)) flags |= HAS_AVX2;
}
}
return flags & mask;
}