#
# Copyright 2013-2021 Software Radio Systems Limited
#
# By using this file, you agree to the terms and conditions set
# forth in the LICENSE file which can be found at the top level of
# the distribution.
#

#if (NOT CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64|^i[3,9]86$")
#   return()
#endif()

include(CheckCSourceRuns)

option(ENABLE_SSE    "Enable compile-time SSE4.1 support." ON)
option(ENABLE_AVX    "Enable compile-time AVX support."    ON)
option(ENABLE_AVX2   "Enable compile-time AVX2 support."   ON)
option(ENABLE_FMA    "Enable compile-time FMA support."    ON)
option(ENABLE_AVX512 "Enable compile-time AVX512 support." ON)

if (ENABLE_SSE)
    #
    # Check compiler for SSE4_1 intrinsics
    #
    if (CMAKE_COMPILER_IS_GNUCC OR (CMAKE_C_COMPILER_ID MATCHES "Clang") OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
        set(CMAKE_REQUIRED_FLAGS "-msse4.1")
        check_c_source_runs("
        #include <emmintrin.h>
        #include <smmintrin.h>

        int main()
        {
        __m128i a = _mm_setzero_si128();
        __m128i b = _mm_minpos_epu16(a);
        return 0;
        }"
        HAVE_SSE)
    endif()

    if (HAVE_SSE)        
        message(STATUS "SSE4.1 is enabled - target CPU must support it")
    endif()
    
    if (ENABLE_AVX)

        #
        # Check compiler for AVX intrinsics
        #
        if (CMAKE_COMPILER_IS_GNUCC OR (CMAKE_C_COMPILER_ID MATCHES "Clang") OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
            set(CMAKE_REQUIRED_FLAGS "-mavx")
            check_c_source_runs("
            #include <immintrin.h>
            int main()
            {
              __m256 a, b, c;
              const float src[8] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
              float dst[8];
              a = _mm256_loadu_ps( src );
              b = _mm256_loadu_ps( src );
              c = _mm256_add_ps( a, b );
              _mm256_storeu_ps( dst, c );
              int i = 0;
              for( i = 0; i < 8; i++ ){
                if( ( src[i] + src[i] ) != dst[i] ){
                  return -1;
                }
              }
              return 0;
            }"
            HAVE_AVX)
        endif()

        if (HAVE_AVX)
            message(STATUS "AVX is enabled - target CPU must support it")
        endif()
    endif()
    
    if (ENABLE_AVX2)

      #
      # Check compiler for AVX intrinsics
      #
      if (CMAKE_COMPILER_IS_GNUCC OR (CMAKE_C_COMPILER_ID MATCHES "Clang") OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
          set(CMAKE_REQUIRED_FLAGS "-mavx2")
          check_c_source_runs("
          #include <immintrin.h>
          int main()
          {
            __m256i a, b, c;
            const int src[8] = { 1, 2, 3, 4, 5, 6, 7, 8 };
            int dst[8];
            a =  _mm256_loadu_si256( (__m256i*)src );
            b =  _mm256_loadu_si256( (__m256i*)src );
            c = _mm256_add_epi32( a, b );
            _mm256_storeu_si256( (__m256i*)dst, c );
            int i = 0;
            for( i = 0; i < 8; i++ ){
              if( ( src[i] + src[i] ) != dst[i] ){
                return -1;
              }
            }
            return 0;
          }"
          HAVE_AVX2)
      endif()

      if (HAVE_AVX2)
          message(STATUS "AVX2 is enabled - target CPU must support it")
      endif()
    endif()

    if (ENABLE_FMA)

        #
        # Check compiler for AVX intrinsics
        #
        if (CMAKE_COMPILER_IS_GNUCC OR (CMAKE_C_COMPILER_ID MATCHES "Clang") OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
            set(CMAKE_REQUIRED_FLAGS "-mfma")
            check_c_source_runs("
            #include <immintrin.h>
            int main()
            {
              __m256 a, b, c, r;
              const float src[8] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
              float dst[8];
              a = _mm256_loadu_ps( src );
              b = _mm256_loadu_ps( src );
              c = _mm256_loadu_ps( src );
              r = _mm256_fmadd_ps( a, b, c );
              _mm256_storeu_ps( dst, r );
              int i = 0;
              for( i = 0; i < 8; i++ ){
                if( ( src[i] * src[i] + src[i] ) != dst[i] ){
                  return -1;
                }
              }
              return 0;
            }"
                    HAVE_FMA)
        endif()

        if (HAVE_FMA)
            message(STATUS "FMA is enabled - target CPU must support it")
        endif()
    endif()

    if (ENABLE_AVX512)

        #
        # Check compiler for AVX intrinsics
        #
        if (CMAKE_COMPILER_IS_GNUCC OR (CMAKE_C_COMPILER_ID MATCHES "Clang") OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
            set(CMAKE_REQUIRED_FLAGS "-mavx512f -mavx512cd -mavx512bw -mavx512dq -DLV_HAVE_AVX512")
            check_c_source_runs("
          #include <immintrin.h>
          int main()
          {
            __m512i a, b, c;
            const int src[16] = { 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8 , 0x9, 0xA, 0xB, 0xC, 0xD, 0xE, 0xF};
            int dst[16];
            a =  _mm512_loadu_si512( (__m512i*)src );
            b =  _mm512_loadu_si512( (__m512i*)src );
            c = _mm512_add_epi32( a, b );
            _mm512_storeu_si512( (__m512i*)dst, c );
            int i = 0;
            for( i = 0; i < 16; i++ ){
              if( ( src[i] + src[i] ) != dst[i] ){
                return -1;
              }
            }
            return 0;
          }"
                    HAVE_AVX512)
        endif()

        if (HAVE_AVX512)
            message(STATUS "AVX512 is enabled - target CPU must support it")
        endif()
    elseif (${GCC_ARCH} MATCHES "native" AND CMAKE_CXX_COMPILER_ID MATCHES "GNU")
        # When GCC flag -march=native and the CPU supports AVX512 (skylake-avx512 architecture), GCC uses AVX512 instructions
        # automatically, independently of the rest of flags.

        # Get the CPU architecture
        execute_process(COMMAND ${CMAKE_C_COMPILER} -march=native -Q --help=target
                OUTPUT_VARIABLE DETECT_SKYLAKE_AVX512)

        # Check if the native architecture matches with skylake-avx512
        if (${DETECT_SKYLAKE_AVX512} MATCHES "march=.*skylake-avx512")
            # Force skylake architecture without AVX512
            set(GCC_ARCH "skylake")
            message(STATUS "This is a skylake-avx512 CPU, as AVX512 was disabled the architecture will be set to skylake")
        endif ()
    endif()


endif()

mark_as_advanced(HAVE_SSE, HAVE_AVX, HAVE_AVX2, HAVE_FMA, HAVE_AVX512)