/* From

https://github.com/endorno/pytorch/blob/master/torch/lib/TH/generic/simd/simd.h

Highly modified.

Copyright (c) 2016-     Facebook, Inc            (Adam Paszke)

Copyright (c) 2014-     Facebook, Inc            (Soumith Chintala)

Copyright (c) 2011-2014 Idiap Research Institute (Ronan Collobert)

Copyright (c) 2012-2014 Deepmind Technologies    (Koray Kavukcuoglu)

Copyright (c) 2011-2012 NEC Laboratories America (Koray Kavukcuoglu)

Copyright (c) 2011-2013 NYU                      (Clement Farabet)

Copyright (c) 2006-2010 NEC Laboratories America (Ronan Collobert, Leon Bottou,

Iain Melvin, Jason Weston) Copyright (c) 2006      Idiap Research Institute

(Samy Bengio) Copyright (c) 2001-2004 Idiap Research Institute (Ronan Collobert,

Samy Bengio, Johnny Mariethoz)

All rights reserved.

Redistribution and use in source and binary forms, with or without

modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright

   notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright

   notice, this list of conditions and the following disclaimer in the

   documentation and/or other materials provided with the distribution.

3. Neither the names of Facebook, Deepmind Technologies, NYU, NEC Laboratories

America and IDIAP Research Institute nor the names of its contributors may be

   used to endorse or promote products derived from this software without

   specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

POSSIBILITY OF SUCH DAMAGE.

*/

#ifndef SIMDJSON_INTERNAL_ISADETECTION_H

#define SIMDJSON_INTERNAL_ISADETECTION_H

#include "simdjson/internal/instruction_set.h"

#include <cstdint>

#include <cstdlib>

#if defined(_MSC_VER)

#include <intrin.h>

#elif defined(HAVE_GCC_GET_CPUID) && defined(USE_GCC_GET_CPUID)

#include <cpuid.h>

#endif

#if defined(__loongarch__) && defined(__linux__)

  #include <sys/auxv.h>

#endif

namespace simdjson {

namespace internal {

#if defined(__PPC64__)

static inline uint32_t detect_supported_architectures() {

  return instruction_set::ALTIVEC;

}

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

static inline uint32_t detect_supported_architectures() {

  return instruction_set::NEON;

}

#elif defined(__x86_64__) || defined(_M_AMD64) // x64

namespace {

// Can be found on Intel ISA Reference for CPUID

constexpr uint32_t cpuid_avx2_bit = 1 << 5;         ///< @private Bit 5 of EBX for EAX=0x7

constexpr uint32_t cpuid_bmi1_bit = 1 << 3;         ///< @private bit 3 of EBX for EAX=0x7

constexpr uint32_t cpuid_bmi2_bit = 1 << 8;         ///< @private bit 8 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512f_bit = 1 << 16;     ///< @private bit 16 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512dq_bit = 1 << 17;    ///< @private bit 17 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512ifma_bit = 1 << 21;  ///< @private bit 21 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512pf_bit = 1 << 26;    ///< @private bit 26 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512er_bit = 1 << 27;    ///< @private bit 27 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512cd_bit = 1 << 28;    ///< @private bit 28 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512bw_bit = 1 << 30;    ///< @private bit 30 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512vl_bit = 1U << 31;    ///< @private bit 31 of EBX for EAX=0x7

constexpr uint32_t cpuid_avx512vbmi2_bit = 1 << 6;  ///< @private bit 6 of ECX for EAX=0x7

constexpr uint64_t cpuid_avx256_saved = uint64_t(1) << 2; ///< @private bit 2 = AVX

constexpr uint64_t cpuid_avx512_saved = uint64_t(7) << 5; ///< @private bits 5,6,7 = opmask, ZMM_hi256, hi16_ZMM

constexpr uint32_t cpuid_sse42_bit = 1 << 20;       ///< @private bit 20 of ECX for EAX=0x1

constexpr uint32_t cpuid_osxsave = (uint32_t(1) << 26) | (uint32_t(1) << 27); ///< @private bits 26+27 of ECX for EAX=0x1

constexpr uint32_t cpuid_pclmulqdq_bit = 1 << 1;    ///< @private bit  1 of ECX for EAX=0x1

}

static inline void cpuid(uint32_t *eax, uint32_t *ebx, uint32_t *ecx,

                         uint32_t *edx) {

#if defined(_MSC_VER)

  int cpu_info[4];

  __cpuidex(cpu_info, *eax, *ecx);

  *eax = cpu_info[0];

  *ebx = cpu_info[1];

  *ecx = cpu_info[2];

  *edx = cpu_info[3];

#elif defined(HAVE_GCC_GET_CPUID) && defined(USE_GCC_GET_CPUID)

  uint32_t level = *eax;

  __get_cpuid(level, eax, ebx, ecx, edx);

#else

  uint32_t a = *eax, b, c = *ecx, d;

  asm volatile("cpuid\n\t" : "+a"(a), "=b"(b), "+c"(c), "=d"(d));

  *eax = a;

  *ebx = b;

  *ecx = c;

  *edx = d;

#endif

}

static inline uint64_t xgetbv() {

#if defined(_MSC_VER)

  return _xgetbv(0);

#else

  uint32_t xcr0_lo, xcr0_hi;

  asm volatile("xgetbv\n\t" : "=a" (xcr0_lo), "=d" (xcr0_hi) : "c" (0));

  return xcr0_lo | (uint64_t(xcr0_hi) << 32);

#endif

}

static inline uint32_t detect_supported_architectures() {

  uint32_t eax, ebx, ecx, edx;

  uint32_t host_isa = 0x0;

  // EBX for EAX=0x1

  eax = 0x1;

  ecx = 0x0;

  cpuid(&eax, &ebx, &ecx, &edx);

  if (ecx & cpuid_sse42_bit) {

    host_isa |= instruction_set::SSE42;

  } else {

    return host_isa; // everything after is redundant

  }

  if (ecx & cpuid_pclmulqdq_bit) {

    host_isa |= instruction_set::PCLMULQDQ;

  }

  if ((ecx & cpuid_osxsave) != cpuid_osxsave) {

    return host_isa;

  }

  // xgetbv for checking if the OS saves registers

  uint64_t xcr0 = xgetbv();

  if ((xcr0 & cpuid_avx256_saved) == 0) {

    return host_isa;

  }

  // ECX for EAX=0x7

  eax = 0x7;

  ecx = 0x0;

  cpuid(&eax, &ebx, &ecx, &edx);

  if (ebx & cpuid_avx2_bit) {

    host_isa |= instruction_set::AVX2;

  }

  if (ebx & cpuid_bmi1_bit) {

    host_isa |= instruction_set::BMI1;

  }

  if (ebx & cpuid_bmi2_bit) {

    host_isa |= instruction_set::BMI2;

  }

  if (!((xcr0 & cpuid_avx512_saved) == cpuid_avx512_saved)) {

     return host_isa;

  }

  if (ebx & cpuid_avx512f_bit) {

    host_isa |= instruction_set::AVX512F;

  }

  if (ebx & cpuid_avx512dq_bit) {

    host_isa |= instruction_set::AVX512DQ;

  }

  if (ebx & cpuid_avx512ifma_bit) {

    host_isa |= instruction_set::AVX512IFMA;

  }

  if (ebx & cpuid_avx512pf_bit) {

    host_isa |= instruction_set::AVX512PF;

  }

  if (ebx & cpuid_avx512er_bit) {

    host_isa |= instruction_set::AVX512ER;

  }

  if (ebx & cpuid_avx512cd_bit) {

    host_isa |= instruction_set::AVX512CD;

  }

  if (ebx & cpuid_avx512bw_bit) {

    host_isa |= instruction_set::AVX512BW;

  }

  if (ebx & cpuid_avx512vl_bit) {

    host_isa |= instruction_set::AVX512VL;

  }

  if (ecx & cpuid_avx512vbmi2_bit) {

    host_isa |= instruction_set::AVX512VBMI2;

  }

  return host_isa;

}

#elif defined(__loongarch__)

static inline uint32_t detect_supported_architectures() {

  uint32_t host_isa = instruction_set::DEFAULT;

  #if defined(__linux__)

  uint64_t hwcap = 0;

  hwcap = getauxval(AT_HWCAP);

  if (hwcap & HWCAP_LOONGARCH_LSX) {

    host_isa |= instruction_set::LSX;

  }

  if (hwcap & HWCAP_LOONGARCH_LASX) {

    host_isa |= instruction_set::LASX;

  }

  #endif

  return host_isa;

}

#elif SIMDJSON_IS_RISCV64

static inline uint32_t detect_supported_architectures() {

  uint32_t host_isa = instruction_set::DEFAULT;

#if SIMDJSON_IS_RVV_VLS

  host_isa |= instruction_set::RVV_VLS;

#endif

  return host_isa;

}

#else // fallback

static inline uint32_t detect_supported_architectures() {

  return instruction_set::DEFAULT;

}

#endif // end SIMD extension detection code

} // namespace internal

} // namespace simdjson

#endif // SIMDJSON_INTERNAL_ISADETECTION_H