main.cpp
#include <stdio.h> #include "../../commonfiles/miscdefs.h" #include <memory.h> // This structure is used to save cpuid instruction results. It must // match the structure that's defined in AvxCpuid_.asm. typedef struct { Uint32 EAX; Uint32 EBX; Uint32 ECX; Uint32 EDX; } CpuidRegs; // This structure contains status flags for cpuid reportable features // used in this book. typedef struct { // General information Uint32 MaxEAX; // Maximum EAX value supported by cpuid char VendorId[13]; // Processor vendor id string // Processor feature flags. Set to 'true' if feature extension // or instruction group is available for use. bool SSE; bool SSE2; bool SSE3; bool SSSE3; bool SSE4_1; bool SSE4_2; bool AVX; bool AVX2; bool F16C; bool FMA; bool POPCNT; bool BMI1; bool BMI2; bool LZCNT; bool MOVBE; // OS enabled feature information bool OSXSAVE; // True if XSAVE feature set is enabled by the OS bool SSE_STATE; // True if XMM state is enabled by the OS bool AVX_STATE; // True if YMM state is enabled by the OS } CpuidFeatures; extern "C" Uint32 Cpuid(Uint32 r_eax, Uint32 r_ecx, CpuidRegs* out); extern "C" void Xgetbv(Uint32 r_ecx, Uint32* r_eax, Uint32* r_edx); // This function will not work on older CPUs, especially // those introduced before 2006. It has been tested using // only Windows 7 (SP1) and Windows 8.1. void GetCpuidFeatures(CpuidFeatures* cf) { CpuidRegs r_out; memset(cf, 0, sizeof(CpuidFeatures)); // Get MaxEAX and VendorID Cpuid(0, 0, &r_out); cf->MaxEAX = r_out.EAX; *(Uint32 *)(cf->VendorId + 0) = r_out.EBX; *(Uint32 *)(cf->VendorId + 4) = r_out.EDX; *(Uint32 *)(cf->VendorId + 8) = r_out.ECX; cf->VendorId[12] = '\0'; // Quit if processor is too old if (cf->MaxEAX < 10) return; // Get CPUID.01H feature flags Cpuid(1, 0, &r_out); Uint32 cpuid01_ecx = r_out.ECX; Uint32 cpuid01_edx = r_out.EDX; // Get CPUID (EAX = 07H, ECX = 00H) feature flags Cpuid(7, 0, &r_out); Uint32 cpuid07_ebx = r_out.EBX; // CPUID.01H:EDX.SSE[bit 25] cf->SSE = (cpuid01_edx & (0x1 << 25)) ? true : false; // CPUID.01H:EDX.SSE2[bit 26] if (cf->SSE) cf->SSE2 = (cpuid01_edx & (0x1 << 26)) ? true : false; // CPUID.01H:ECX.SSE3[bit 0] if (cf->SSE2) cf->SSE3 = (cpuid01_ecx & (0x1 << 0)) ? true : false; // CPUID.01H:ECX.SSSE3[bit 9] if (cf->SSE3) cf->SSSE3 = (cpuid01_ecx & (0x1 << 9)) ? true : false; // CPUID.01H:ECX.SSE4.1[bit 19] if (cf->SSSE3) cf->SSE4_1 = (cpuid01_ecx & (0x1 << 19)) ? true : false; // CPUID.01H:ECX.SSE4.2[bit 20] if (cf->SSE4_1) cf->SSE4_2 = (cpuid01_ecx & (0x1 << 20)) ? true : false; // CPUID.01H:ECX.POPCNT[bit 23] if (cf->SSE4_2) cf->POPCNT = (cpuid01_ecx & (0x1 << 23)) ? true : false; // CPUID.01H:ECX.OSXSAVE[bit 27] cf->OSXSAVE = (cpuid01_ecx & (0x1 << 27)) ? true : false; // Test OSXSAVE status to verify XGETBV is enabled if (cf->OSXSAVE) { // Use XGETBV to obtain following information // XSAVE uses SSE state if (XCR0[1] == 1) is true // XSAVE uses AVX state if (XCR0[2] == 1) is true Uint32 xgetbv_eax, xgetbv_edx; Xgetbv(0, &xgetbv_eax, &xgetbv_edx); cf->SSE_STATE = (xgetbv_eax & (0x1 << 1)) ? true : false; cf->AVX_STATE = (xgetbv_eax & (0x1 << 2)) ? true : false; // Is SSE and AVX state information supported by the OS? if (cf->SSE_STATE && cf->AVX_STATE) { // CPUID.01H:ECX.AVX[bit 28] = 1 cf->AVX = (cpuid01_ecx & (0x1 << 28)) ? true : false; if (cf->AVX) { // CPUID.01H:ECX.F16C[bit 29] cf->F16C = (cpuid01_ecx & (0x1 << 29)) ? true : false; // CPUID.01H:ECX.FMA[bit 12] cf->FMA = (cpuid01_ecx & (0x1 << 12)) ? true : false; // CPUID.(EAX = 07H, ECX = 00H):EBX.AVX2[bit 5] cf->AVX2 = (cpuid07_ebx & (0x1 << 5)) ? true : false; } } } // CPUID.(EAX = 07H, ECX = 00H):EBX.BMI1[bit 3] cf->BMI1 = (cpuid07_ebx & (0x1 << 3)) ? true : false; // CPUID.(EAX = 07H, ECX = 00H):EBX.BMI2[bit 8] cf->BMI2 = (cpuid07_ebx & (0x1 << 8)) ? true : false; // CPUID.80000001H:ECX.LZCNT[bit 5] Cpuid(0x80000001, 0, &r_out); cf->LZCNT = (r_out.ECX & (0x1 << 5)) ? true : false; // Get MOVBE // CPUID.01H:ECX.MOVBE[bit 22] cf->MOVBE = cpuid01_ecx & (0x1 << 22) ? true : false; } int main(int argc, char* argv[]) { CpuidFeatures cf; GetCpuidFeatures(&cf); printf("Results for AvxCpuid\n"); printf("MaxEAX: %d\n", cf.MaxEAX); printf("VendorId: %s\n", cf.VendorId); printf("SSE: %d\n", cf.SSE); printf("SSE2: %d\n", cf.SSE2); printf("SSE3: %d\n", cf.SSE3); printf("SSSE3: %d\n", cf.SSSE3); printf("SSE4_1: %d\n", cf.SSE4_1); printf("SSE4_2: %d\n", cf.SSE4_2); printf("POPCNT: %d\n", cf.POPCNT); printf("AVX: %d\n", cf.AVX); printf("F16C: %d\n", cf.F16C); printf("FMA: %d\n", cf.FMA); printf("AVX2: %d\n", cf.AVX2); printf("BMI1 %d\n", cf.BMI1); printf("BMI2 %d\n", cf.BMI2); printf("LZCNT %d\n", cf.LZCNT); printf("MOVBE %d\n", cf.MOVBE); printf("\n"); printf("OSXSAVE %d\n", cf.OSXSAVE); printf("SSE_STATE %d\n", cf.SSE_STATE); printf("AVX_STATE %d\n", cf.AVX_STATE); return 0; }
avxcpuid.asm
; Name: avxcpuid.asm ; ; Build: g++ -c -m32 main.cpp -o main.o ; nasm -f elf32 -o avxcpuid.o avxcpuid.asm ; g++ -m32 -o avxcpuid avxcpuid.o main.o ; ; Source: Modern x86 Assembly Language Programming p. 439 global Cpuid global Xgetbv ; This structure must match the structure that's defined ; in AvxCpuid.cpp struc CpuidRegs .RegEAX: resd 1 .RegEBX: resd 1 .RegECX: resd 1 .RegEDX: resd 1 endstruc section .text ; extern "C" Uint32 Cpuid(Uint32 r_eax, Uint32 r_ecx, CpuidRegs* r_out); ; ; Description: The following function uses the CPUID instruction to ; query processor identification and feature information. ; ; Returns: eax == 0 Unsupported CPUID leaf ; eax != 0 Supported CPUID leaf ; ; The return code is valid only if r_eax <= MaxEAX. Cpuid: push ebp mov ebp,esp push ebx push esi ; Load eax and ecx with provided values, then use cpuid mov eax,[ebp+8] mov ecx,[ebp+12] cpuid ; Save results mov esi,[ebp+16] mov [esi+CpuidRegs.RegEAX],eax mov [esi+CpuidRegs.RegEBX],ebx mov [esi+CpuidRegs.RegECX],ecx mov [esi+CpuidRegs.RegEDX],edx ; Test for unsupported CPUID leaf or eax,ebx or ecx,edx or eax,ecx ;eax = return code pop esi pop ebx pop ebp ret ; extern "C" void Xgetbv(Uint32 r_ecx, Uint32* r_eax, Uint32* r_edx); ; ; Description: The following function uses the XGETBV instruction to ; obtain the contents of the extended control register ; that's specified by r_ecx. ; ; Notes: A processor exception will occur if r_ecx is invalid ; or if the XSAVE feature set is disabled. Xgetbv: push ebp mov ebp,esp mov ecx,[ebp+8] ;ecx = extended control reg xgetbv mov ecx,[ebp+12] mov [ecx],eax ;save result (low dword) mov ecx,[ebp+16] mov [ecx],edx ;save result (high dword) pop ebp ret
build
g++ -c -m32 main.cpp -o main.o nasm -f elf32 -o avxcpuid.o avxcpuid.asm g++ -m32 -o avxcpuid avxcpuid.o main.o