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#include <stdbool.h>
#include "cpu_features.h"
/* level 1 edx bits */
#define EDX_CX8 (1 << 8) /* CMPXCHG8B */
#define EDX_CMOV (1 << 15)
#define EDX_MMX (1 << 23)
#define EDX_FXSR (1 << 24) /* FXSAVE and FXRSTOR */
#define EDX_SSE (1 << 25)
#define EDX_SSE2 (1 << 26)
/* level 1 ecx bits */
#define ECX_SSE3 (1 << 0)
#define ECX_CX16 (1 << 13) /* CMPXCHG16B */
/* extended level 0x80000001 edx bits */
#define EDX_3DNOW (1 << 31)
#define EDX_3DNOWP (1 << 30)
#define EDX_LM (1 << 29) /*LONG MODE */
#define __cpuid(level,a,b,c,d) \
asm volatile ("cpuid;" \
: "=a" (a), "=b" (b), "=c" (c), "=d" (d)\
: "0" (level))
/* Combine the different cpuid flags into a single bitmap. */
unsigned int __cpu_features = 0;
void __cpu_features_init (void)
{
unsigned int eax, ebx, ecx, edx;
/* Try to change the value of CPUID bit (bit 21) in EFLAGS.
If the bit can be toggled, CPUID is supported. */
asm volatile ("pushfl; pushfl; popl %0;"
"movl %0,%1; xorl %2,%0;"
"pushl %0; popfl; pushfl; popl %0; popfl"
: "=&r" (eax), "=&r" (ebx)
: "i" (0x00200000));
if (((eax ^ ebx) & 0x00200000) == 0)
return;
__cpuid (0, eax, ebx, ecx, edx);
if (eax == 0)
return;
__cpuid (1, eax, ebx, ecx, edx);
if (edx & EDX_CX8)
__cpu_features |= _CRT_CMPXCHG8B;
if (edx & EDX_CMOV)
__cpu_features |= _CRT_CMOV;
if (edx & EDX_MMX)
__cpu_features |= _CRT_MMX;
if (edx & EDX_FXSR)
__cpu_features |= _CRT_FXSR;
if (edx & EDX_SSE)
__cpu_features |= _CRT_SSE;
if (edx & EDX_SSE2)
__cpu_features |= _CRT_SSE2;
if (ecx & ECX_SSE3)
__cpu_features |= _CRT_SSE3;
if (ecx & ECX_CX16)
__cpu_features |= _CRT_CMPXCHG16B;
__cpuid (0x80000000, eax, ebx, ecx, edx);
if (eax < 0x80000001)
return;
__cpuid (0x80000001, eax, ebx, ecx, edx);
if (edx & EDX_3DNOW)
__cpu_features |= _CRT_3DNOW;
if (edx & EDX_3DNOWP)
__cpu_features |= _CRT_3DNOWP;
return;
}
#ifdef TEST
#include <stdio.h>
#define report(feature) \
if ((feature) & __cpu_features) printf( #feature " found\n")
int main()
{
__cpu_features_init();
report(_CRT_CMPXCHG8B);
report(_CRT_CMOV);
report(_CRT_MMX);
report(_CRT_FXSR);
report(_CRT_SSE);
report(_CRT_SSE2);
report(_CRT_SSE3);
report(_CRT_CMPXCHG16B);
report(_CRT_3DNOW);
report(_CRT_3DNOWP);
return 0;
}
#endif
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