/*

 * Copyright Supranational LLC

 * Licensed under the Apache License, Version 2.0, see LICENSE for details.

 * SPDX-License-Identifier: Apache-2.0

 */

#if (defined(__GNUC__) || defined(__clang__) || defined(__SUNPRO_C)) && !defined(_WIN32)

__attribute__((visibility("hidden")))

#endif

int __blst_platform_cap = 0;

#if defined(__x86_64__) || defined(__x86_64) || (defined(_M_X64) && !defined(_M_ARM64EC))

# if defined(__GNUC__) || defined(__clang__) || defined(__SUNPRO_C)

static void __cpuidex(int info[4], int func, int sub)

{

    int eax, ebx, ecx, edx;

    __asm__("cpuid" : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx)

                    : "a"(func), "c"(sub));

    info[0] = eax;

    info[1] = ebx;

    info[2] = ecx;

    info[3] = edx;

}

# else

#  include <intrin.h>

# endif

# if defined(__GNUC__) || defined(__clang__)

__attribute__((constructor))

# endif

static int __blst_cpuid(void)

{

    int info[4], cap = 0;

    __cpuidex(info, 0, 0);

    if (info[0] > 6) {

        __cpuidex(info, 7, 0);

        cap |= (info[1]>>19) & 1; /* ADX */

        cap |= (info[1]>>28) & 2; /* SHA */

    }

    __blst_platform_cap = cap;

    return 0;

}

# if defined(_MSC_VER) && !defined(__clang__) && !defined(__BLST_DLL_MAIN__)

#  pragma section(".CRT$XCU",read)

__declspec(allocate(".CRT$XCU")) static int (*p)(void) = __blst_cpuid;

# elif defined(__SUNPRO_C)

#  pragma init(__blst_cpuid)

# endif

#elif defined(__aarch64__) || defined(__aarch64) || defined(_M_ARM64) || defined(_M_ARM64EC)

# if defined(__linux__) && (defined(__GNUC__) || defined(__clang__))

extern unsigned long getauxval(unsigned long type) __attribute__ ((weak));

__attribute__((constructor))

static int __blst_cpuid(void)

{

    int cap = 0;

    if (getauxval) {

        unsigned long hwcap_ce = getauxval(16);

        cap = (hwcap_ce>>6) & 1; /* SHA256 */

    }

    __blst_platform_cap = cap;

    return 0;

}

# elif defined(__APPLE__) && (defined(__GNUC__) || defined(__clang__))

__attribute__((constructor))

static int __blst_cpuid()

{

    __blst_platform_cap = 1; /* SHA256 */

    return 0;

}

# elif defined(__FreeBSD__) && __FreeBSD__ >= 12

#  include <sys/auxv.h>

__attribute__((constructor))

static int __blst_cpuid()

{

    unsigned long cap;

    if (elf_aux_info(AT_HWCAP, &cap, sizeof(cap)) == 0)

        __blst_platform_cap = (cap & HWCAP_SHA2) != 0;

    return 0;

}

# elif defined(_WIN64)

int IsProcessorFeaturePresent(int);

#  if defined(__GNUC__) || defined(__clang__)

__attribute__((constructor))

#  endif

static int __blst_cpuid(void)

{

    __blst_platform_cap = IsProcessorFeaturePresent(30); /* AES, SHA1, SHA2 */

    return 0;

}

#  if defined(_MSC_VER) && !defined(__clang__) && !defined(__BLST_DLL_MAIN__)

#   pragma section(".CRT$XCU",read)

__declspec(allocate(".CRT$XCU")) static int (*p)(void) = __blst_cpuid;

#  endif

# endif

#endif

#if defined(_WIN64) && defined(__BLST_DLL_MAIN__)

# define IsProcessorFeaturePresent mask_IsProcessorFeaturePresent

# define WIN32_LEAN_AND_MEAN

# include <windows.h>

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD dwReason, LPVOID lpvReserved)

{

    if (dwReason == DLL_PROCESS_ATTACH) {

        DisableThreadLibraryCalls(hinstDLL);

        __blst_cpuid();

    }

    return TRUE;

    (void)lpvReserved;

}

# if defined(_MSC_VER)

/*

 * Even though we don't have memcpy/memset anywhere, MSVC compiler

 * generates calls to them as it recognizes corresponding patterns.

 */

#pragma function(memcpy)

void *memcpy(unsigned char *dst, const unsigned char *src, size_t n)

{

    void *ret = dst;

    while(n--)

        *dst++ = *src++;

    return ret;

}

#pragma function(memset)

void *memset(unsigned char *dst, int c, size_t n)

{

    void *ret = dst;

    while(n--)

        *dst++ = (unsigned char)c;

    return ret;

}

# endif

#endif