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Correctness fixes to AVX check.

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This commit is contained in:
Themaister 2013-12-29 11:48:00 +01:00
parent 8d2222d3b5
commit 17559a3a18
1 changed files with 17 additions and 4 deletions
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21
performance.c
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@ -29,6 +29,7 @@
#if defined(_WIN32) && !defined(_XBOX)
#include <windows.h>
#include <intrin.h>
#endif
#if defined(__CELLOS_LV2__) || defined(GEKKO)
@ -238,11 +239,23 @@ static void x86_cpuid(int func, int flags[4])
#endif
}
static uint64_t _xgetbv(uint32_t index)
// Only runs on i686 and above. Needs to be conditionally run.
static uint64_t xgetbv_x86(uint32_t index)
{
#if defined(__GNUC__)
uint32_t eax, edx;
__asm__ __volatile__("xgetbv" : "=a"(eax), "=d"(edx) : "c"(index));
asm volatile (
// Older GCC versions (Apple's GCC for example) do not understand xgetbv instruction.
// Stamp out the machine code directly.
".byte 0x0f, 0x01, 0xd0\n"
: "=a"(eax), "=d"(edx) : "c"(index));
return ((uint64_t)edx << 32) | eax;
#elif _MSC_FULL_VER >= 160040219 // Intrinsic only works on 2010 SP1 and above.
return _xgetbv(index);
#else
RARCH_WARN("Unknown compiler. Cannot check xgetbv bits.\n");
return 0;
#endif
}
#endif
@ -280,8 +293,8 @@ uint64_t rarch_get_cpu_features(void)
cpu |= RETRO_SIMD_SSSE3;
const int avx_flags = (1 << 27) | (1 << 28);
const bool xcr_bit_set = ((_xgetbv(0) & 0x6) == 0x6);
if ((flags[2] & avx_flags) == avx_flags && xcr_bit_set)
// Must only perform xgetbv check if we have AVX CPU support (guaranteed to have at least i686).
if (((flags[2] & avx_flags) == avx_flags) && ((xgetbv_x86(0) & 0x6) == 0x6))
cpu |= RETRO_SIMD_AVX;
RARCH_LOG("[CPUID]: MMX: %u\n", !!(cpu & RETRO_SIMD_MMX));