Get supported SIMD instruction sets (x86 only)

x86-simd.c

#include <stdio.h>

#define SIMD_SSE     0x1
#define SIMD_SSE2    0x2
#define SIMD_SSE3    0x4
#define SIMD_SSSE3   0x8
#define SIMD_SSE4_1  0x10
#define SIMD_SSE4_2  0x20
#define SIMD_AVX     0x40
#define SIMD_AVX2    0x80
#define SIMD_AVX512F 0x100

#ifndef _MSC_VER
// adapted from https://github.com/01org/linux-sgx/blob/master/common/inc/internal/linux/cpuid_gnu.h
void __cpuidex(int cpuid[4], int func_id, int subfunc_id)
{
#if defined(__x86_64__)
	asm volatile ("cpuid"
			: "=a" (cpuid[0]), "=b" (cpuid[1]), "=c" (cpuid[2]), "=d" (cpuid[3])
			: "0" (func_id), "2" (subfunc_id));
#else // on 32bit, ebx can NOT be used as PIC code
	asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1"
			: "=a" (cpuid[0]), "=r" (cpuid[1]), "=c" (cpuid[2]), "=d" (cpuid[3])
			: "0" (func_id), "2" (subfunc_id));
#endif
}
#endif

int x86_simd(void)
{
	int flag = 0, cpuid[4], max_id;
	__cpuidex(cpuid, 0, 0);
	max_id = cpuid[0];
	if (max_id == 0) return 0;
	__cpuidex(cpuid, 1, 0);
	if (cpuid[3]>>25&1) flag |= SIMD_SSE;
	if (cpuid[3]>>26&1) flag |= SIMD_SSE2;
	if (cpuid[2]>>0 &1) flag |= SIMD_SSE3;
	if (cpuid[2]>>9 &1) flag |= SIMD_SSSE3;
	if (cpuid[2]>>19&1) flag |= SIMD_SSE4_1;
	if (cpuid[2]>>20&1) flag |= SIMD_SSE4_2;
	if (cpuid[2]>>28&1) flag |= SIMD_AVX;
	if (max_id >= 7) {
		__cpuidex(cpuid, 7, 0);
		if (cpuid[1]>>5 &1) flag |= SIMD_AVX2;
		if (cpuid[1]>>16&1) flag |= SIMD_AVX512F;
	}
	return flag;
}

const char *simd_name[9] = { "sse", "sse2", "sse3", "ssse3", "sse4.1", "sse4.2", "avx", "avx2", "avx512f" };

int main()
{
	unsigned i, simd_flag;
	simd_flag = x86_simd();
	for (i = 0; i < 8; ++i)
		if (simd_flag>>i&1) puts(simd_name[i]);
	return 0;
}