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/************************** instrset_detect.cpp ****************************
| Author: Agner Fog
| Date created: 2012-05-30
* Last modified: 2016-04-26
* Version: 1.22
| Project: vector classes
| Description:
| Functions for checking which instruction sets are supported.
|
| (c) Copyright 2012-2016 GNU General Public License http://www.gnu.org/licenses
\*****************************************************************************/
#include "instrset.h"
#ifdef VCL_NAMESPACE
namespace VCL_NAMESPACE {
#endif
// Define interface to cpuid instruction.
// input: eax = functionnumber, ecx = 0
// output: eax = output[0], ebx = output[1], ecx = output[2], edx = output[3]
static inline void cpuid (int output[4], int functionnumber) {
#if defined (_MSC_VER) //|| defined (__INTEL_COMPILER) // Microsoft or Intel compiler, intrin.h included
__cpuidex(output, functionnumber, 0); // intrinsic function for CPUID
#elif defined(__GNUC__) || defined(__clang__) || defined (__INTEL_COMPILER) // use inline assembly, Gnu/AT&T syntax
int a, b, c, d;
__asm("cpuid" : "=a"(a),"=b"(b),"=c"(c),"=d"(d) : "a"(functionnumber),"c"(0) : );
output[0] = a;
output[1] = b;
output[2] = c;
output[3] = d;
#else // unknown platform. try inline assembly with masm/intel syntax
__asm {
mov eax, functionnumber
xor ecx, ecx
cpuid;
mov esi, output
mov [esi], eax
mov [esi+4], ebx
mov [esi+8], ecx
mov [esi+12], edx
}
#endif
}
// Define interface to xgetbv instruction
static inline int64_t xgetbv (int ctr) {
#if (defined (_MSC_FULL_VER) && _MSC_FULL_VER >= 160040000) || (defined (__INTEL_COMPILER) && __INTEL_COMPILER >= 1200) // Microsoft or Intel compiler supporting _xgetbv intrinsic
return _xgetbv(ctr); // intrinsic function for XGETBV
#elif defined(__GNUC__) // use inline assembly, Gnu/AT&T syntax
uint32_t a, d;
__asm("xgetbv" : "=a"(a),"=d"(d) : "c"(ctr) : );
return a | (uint64_t(d) << 32);
#else // #elif defined (_WIN32) // other compiler. try inline assembly with masm/intel/MS syntax
uint32_t a, d;
__asm {
mov ecx, ctr
_emit 0x0f
_emit 0x01
_emit 0xd0 ; // xgetbv
mov a, eax
mov d, edx
}
return a | (uint64_t(d) << 32);
#endif
}
/* find supported instruction set
return value:
0 = 80386 instruction set
1 or above = SSE (XMM) supported by CPU (not testing for O.S. support)
2 or above = SSE2
3 or above = SSE3
4 or above = Supplementary SSE3 (SSSE3)
5 or above = SSE4.1
6 or above = SSE4.2
7 or above = AVX supported by CPU and operating system
8 or above = AVX2
9 or above = AVX512F
*/
int instrset_detect(void) {
static int iset = -1; // remember value for next call
if (iset >= 0) {
return iset; // called before
}
iset = 0; // default value
int abcd[4] = {0,0,0,0}; // cpuid results
cpuid(abcd, 0); // call cpuid function 0
if (abcd[0] == 0) return iset; // no further cpuid function supported
cpuid(abcd, 1); // call cpuid function 1 for feature flags
if ((abcd[3] & (1 << 0)) == 0) return iset; // no floating point
if ((abcd[3] & (1 << 23)) == 0) return iset; // no MMX
if ((abcd[3] & (1 << 15)) == 0) return iset; // no conditional move
if ((abcd[3] & (1 << 24)) == 0) return iset; // no FXSAVE
if ((abcd[3] & (1 << 25)) == 0) return iset; // no SSE
iset = 1; // 1: SSE supported
if ((abcd[3] & (1 << 26)) == 0) return iset; // no SSE2
iset = 2; // 2: SSE2 supported
if ((abcd[2] & (1 << 0)) == 0) return iset; // no SSE3
iset = 3; // 3: SSE3 supported
if ((abcd[2] & (1 << 9)) == 0) return iset; // no SSSE3
iset = 4; // 4: SSSE3 supported
if ((abcd[2] & (1 << 19)) == 0) return iset; // no SSE4.1
iset = 5; // 5: SSE4.1 supported
if ((abcd[2] & (1 << 23)) == 0) return iset; // no POPCNT
if ((abcd[2] & (1 << 20)) == 0) return iset; // no SSE4.2
iset = 6; // 6: SSE4.2 supported
if ((abcd[2] & (1 << 27)) == 0) return iset; // no OSXSAVE
if ((xgetbv(0) & 6) != 6) return iset; // AVX not enabled in O.S.
if ((abcd[2] & (1 << 28)) == 0) return iset; // no AVX
iset = 7; // 7: AVX supported
cpuid(abcd, 7); // call cpuid leaf 7 for feature flags
if ((abcd[1] & (1 << 5)) == 0) return iset; // no AVX2
iset = 8; // 8: AVX2 supported
cpuid(abcd, 0xD); // call cpuid leaf 0xD for feature flags
if ((abcd[0] & 0x60) != 0x60) return iset; // no AVX512
iset = 9; // 8: AVX512F supported
return iset;
}
// detect if CPU supports the FMA3 instruction set
bool hasFMA3(void) {
if (instrset_detect() < 7) return false; // must have AVX
int abcd[4]; // cpuid results
cpuid(abcd, 1); // call cpuid function 1
return ((abcd[2] & (1 << 12)) != 0); // ecx bit 12 indicates FMA3
}
// detect if CPU supports the FMA4 instruction set
bool hasFMA4(void) {
if (instrset_detect() < 7) return false; // must have AVX
int abcd[4]; // cpuid results
cpuid(abcd, 0x80000001); // call cpuid function 0x80000001
return ((abcd[2] & (1 << 16)) != 0); // ecx bit 16 indicates FMA4
}
// detect if CPU supports the XOP instruction set
bool hasXOP(void) {
if (instrset_detect() < 7) return false; // must have AVX
int abcd[4]; // cpuid results
cpuid(abcd, 0x80000001); // call cpuid function 0x80000001
return ((abcd[2] & (1 << 11)) != 0); // ecx bit 11 indicates XOP
}
#ifdef VCL_NAMESPACE
}
#endif
|
