cpu.cpp

// cpu.cpp - written and placed in the public domain by Wei Dai

#include "pch.h"

#ifndef CRYPTOPP_IMPORTS

#include "cpu.h"
#include "misc.h"
#include <algorithm>

#ifdef __GNUC__
#include <signal.h>
#include <setjmp.h>
#endif

#ifdef CRYPTOPP_MSVC6PP_OR_LATER
#include <emmintrin.h>
#endif

NAMESPACE_BEGIN(CryptoPP)

#ifdef CRYPTOPP_X86_ASM_AVAILABLE

#ifndef _MSC_VER
typedef void (*SigHandler)(int);

static jmp_buf s_jmpNoCPUID;
static void SigIllHandlerCPUID(int)
{
        longjmp(s_jmpNoCPUID, 1);
}
#endif

bool CpuId(word32 input, word32 *output)
{
#ifdef _MSC_VER
    __try
        {
                __asm
                {
                        mov eax, input
                        cpuid
                        mov edi, output
                        mov [edi], eax
                        mov [edi+4], ebx
                        mov [edi+8], ecx
                        mov [edi+12], edx
                }
        }
    __except (1)
        {
                return false;
    }
        return true;
#else
        SigHandler oldHandler = signal(SIGILL, SigIllHandlerCPUID);
        if (oldHandler == SIG_ERR)
                return false;

        bool result = true;
        if (setjmp(s_jmpNoCPUID))
                result = false;
        else
        {
                __asm__
                (
                        // save ebx in case -fPIC is being used
#if CRYPTOPP_BOOL_X86
                        "push %%ebx; cpuid; mov %%ebx, %%edi; pop %%ebx"
#else
                        "pushq %%rbx; cpuid; mov %%ebx, %%edi; popq %%rbx"
#endif
                        : "=a" (output[0]), "=D" (output[1]), "=c" (output[2]), "=d" (output[3])
                        : "a" (input)
                );
        }

        signal(SIGILL, oldHandler);
        return result;
#endif
}

#ifndef _MSC_VER
static jmp_buf s_jmpNoSSE2;
static void SigIllHandlerSSE2(int)
{
        longjmp(s_jmpNoSSE2, 1);
}
#endif

#elif _MSC_VER >= 1400 && CRYPTOPP_BOOL_X64

bool CpuId(word32 input, word32 *output)
{
        __cpuid((int *)output, input);
        return true;
}

#endif

#ifdef CRYPTOPP_CPUID_AVAILABLE

static bool TrySSE2()
{
#if CRYPTOPP_BOOL_X64
        return true;
#elif defined(_MSC_VER)
    __try
        {
#if CRYPTOPP_BOOL_SSE2_ASM_AVAILABLE
        AS2(por xmm0, xmm0)        // executing SSE2 instruction
#elif CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
                __mm128i x = _mm_setzero_si128();
                return _mm_cvtsi128_si32(x) == 0;
#endif
        }
    __except (1)
        {
                return false;
    }
        return true;
#elif defined(__GNUC__)
        SigHandler oldHandler = signal(SIGILL, SigIllHandlerSSE2);
        if (oldHandler == SIG_ERR)
                return false;

        bool result = true;
        if (setjmp(s_jmpNoSSE2))
                result = false;
        else
        {
#if CRYPTOPP_BOOL_SSE2_ASM_AVAILABLE
                __asm __volatile ("por %xmm0, %xmm0");
#elif CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
                __mm128i x = _mm_setzero_si128();
                result = _mm_cvtsi128_si32(x) == 0;
#endif
        }

        signal(SIGILL, oldHandler);
        return result;
#else
        return false;
#endif
}

bool g_x86DetectionDone = false;
bool g_hasSSE2 = false, g_hasSSSE3 = false, g_hasMMX = false, g_isP4 = false;
word32 g_cacheLineSize = CRYPTOPP_L1_CACHE_LINE_SIZE;

void DetectX86Features()
{
        word32 cpuid[4], cpuid1[4];
        if (!CpuId(0, cpuid))
                return;
        if (!CpuId(1, cpuid1))
                return;

        g_hasMMX = (cpuid1[3] & (1 << 23)) != 0;
        if ((cpuid1[3] & (1 << 26)) != 0)
                g_hasSSE2 = TrySSE2();
        g_hasSSSE3 = g_hasSSE2 && (cpuid1[2] & (1<<9));

        std::swap(cpuid[2], cpuid[3]);
        if (memcmp(cpuid+1, "GenuineIntel", 12) == 0)
        {
                g_isP4 = ((cpuid1[0] >> 8) & 0xf) == 0xf;
                g_cacheLineSize = 8 * GETBYTE(cpuid1[1], 1);
        }
        else if (memcmp(cpuid+1, "AuthenticAMD", 12) == 0)
        {
                CpuId(0x80000005, cpuid);
                g_cacheLineSize = GETBYTE(cpuid[2], 0);
        }

        if (!g_cacheLineSize)
                g_cacheLineSize = CRYPTOPP_L1_CACHE_LINE_SIZE;

        g_x86DetectionDone = true;
}

#endif

NAMESPACE_END

#endif

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