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BMagnu 95fef2af39 Fix x86 SIMD Extension Handling (#6384)
* Fix AVX2 detection

* Also query for proper OS support

* Actually properly set ISA level on all platforms

* Expose level of x86-SIMD instructions to the code.

* Fix handling of forced instruction set

* Fix errors

* Fix MSVC

* Properly deal with linux CI builds

* fix clang
2024-10-28 17:58:31 +09:00

82 lines
1.5 KiB
C++

// Code snippet from http://stackoverflow.com/a/7495023
#ifdef _WIN32
#include <intrin.h>
// Windows
#define cpuid __cpuidex
#define xgetbv _xgetbv
#else
#include <cstdint>
// GCC Inline Assembly
void cpuid(int CPUInfo[4], int InfoType, int SubType){
__asm__ __volatile__ (
"cpuid":
"=a" (CPUInfo[0]),
"=b" (CPUInfo[1]),
"=c" (CPUInfo[2]),
"=d" (CPUInfo[3]) :
"a" (InfoType),
"c" (SubType)
);
}
uint64_t xgetbv(uint32_t xcr) {
uint32_t lower, higher;
__asm__ __volatile__ (
"xgetbv":
"=a"(lower),
"=d"(higher) :
"c"(xcr)
);
return (static_cast<uint64_t>(higher) << static_cast<uint64_t>(32)) | static_cast<uint64_t>(lower);
}
#endif
#include <iostream>
int main( int argc, char* argv[] )
{
bool SSE = false;
bool SSE2 = false;
bool OSXSAVE = false;
bool AVX = false;
bool AVX2 = false;
int info[4];
cpuid(info, 0, 0);
int nIds = info[0];
// Detect Instruction Set
if (nIds >= 1){
cpuid(info, 0x00000001, 0);
SSE = (info[3] & ((int)1 << 25)) != 0;
SSE2 = (info[3] & ((int)1 << 26)) != 0;
OSXSAVE = (info[2] & ((int)1 << 27)) != 0;
AVX = (info[2] & ((int)1 << 28)) != 0;
}
if (nIds >= 7){
cpuid(info,0x00000007, 0);
AVX2 = (info[1] & ((int)1 << 5)) != 0;
}
// Detect OS Support
if (!OSXSAVE || (xgetbv(0) & 0x6) == 0) {
AVX = false;
AVX2 = false;
}
if (AVX2)
std::cout << "AVX2";
else if(AVX)
std::cout << "AVX";
else if(SSE2)
std::cout << "SSE2";
else if(SSE)
std::cout << "SSE";
return 0;
}