src/nnue/layers/simd.h

/*
  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
  Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)

  Stockfish is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Stockfish is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef STOCKFISH_SIMD_H_INCLUDED
#define STOCKFISH_SIMD_H_INCLUDED

#if defined(USE_AVX2)
# include <immintrin.h>

#elif defined(USE_SSE41)
# include <smmintrin.h>

#elif defined(USE_SSSE3)
# include <tmmintrin.h>

#elif defined(USE_SSE2)
# include <emmintrin.h>

#elif defined(USE_MMX)
# include <mmintrin.h>

#elif defined(USE_NEON)
# include <arm_neon.h>
#endif

// The inline asm is only safe for GCC, where it is necessary to get good codegen.
// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101693
// Clang does fine without it.
// Play around here: https://godbolt.org/z/7EWqrYq51
#if (defined(__GNUC__) && !defined(__clang__) && !defined(__INTEL_COMPILER))
#define USE_INLINE_ASM
#endif

// Use either the AVX512 or AVX-VNNI version of the VNNI instructions.
#if defined(USE_AVXVNNI)
#define VNNI_PREFIX "%{vex%} "
#else
#define VNNI_PREFIX ""
#endif

namespace Stockfish::Simd {

#if defined (USE_AVX512)

    [[maybe_unused]] static int m512_hadd(__m512i sum, int bias) {
      return _mm512_reduce_add_epi32(sum) + bias;
    }

    /*
      Parameters:
        sum0 = [zmm0.i128[0], zmm0.i128[1], zmm0.i128[2], zmm0.i128[3]]
        sum1 = [zmm1.i128[0], zmm1.i128[1], zmm1.i128[2], zmm1.i128[3]]
        sum2 = [zmm2.i128[0], zmm2.i128[1], zmm2.i128[2], zmm2.i128[3]]
        sum3 = [zmm3.i128[0], zmm3.i128[1], zmm3.i128[2], zmm3.i128[3]]

      Returns:
        ret = [
          reduce_add_epi32(zmm0.i128[0]), reduce_add_epi32(zmm1.i128[0]), reduce_add_epi32(zmm2.i128[0]), reduce_add_epi32(zmm3.i128[0]),
          reduce_add_epi32(zmm0.i128[1]), reduce_add_epi32(zmm1.i128[1]), reduce_add_epi32(zmm2.i128[1]), reduce_add_epi32(zmm3.i128[1]),
          reduce_add_epi32(zmm0.i128[2]), reduce_add_epi32(zmm1.i128[2]), reduce_add_epi32(zmm2.i128[2]), reduce_add_epi32(zmm3.i128[2]),
          reduce_add_epi32(zmm0.i128[3]), reduce_add_epi32(zmm1.i128[3]), reduce_add_epi32(zmm2.i128[3]), reduce_add_epi32(zmm3.i128[3])
        ]
    */
    [[maybe_unused]] static __m512i m512_hadd128x16_interleave(
        __m512i sum0, __m512i sum1, __m512i sum2, __m512i sum3) {

      __m512i sum01a = _mm512_unpacklo_epi32(sum0, sum1);
      __m512i sum01b = _mm512_unpackhi_epi32(sum0, sum1);

      __m512i sum23a = _mm512_unpacklo_epi32(sum2, sum3);
      __m512i sum23b = _mm512_unpackhi_epi32(sum2, sum3);

      __m512i sum01 = _mm512_add_epi32(sum01a, sum01b);
      __m512i sum23 = _mm512_add_epi32(sum23a, sum23b);

      __m512i sum0123a = _mm512_unpacklo_epi64(sum01, sum23);
      __m512i sum0123b = _mm512_unpackhi_epi64(sum01, sum23);

      return _mm512_add_epi32(sum0123a, sum0123b);
    }

    [[maybe_unused]] static __m128i m512_haddx4(
        __m512i sum0, __m512i sum1, __m512i sum2, __m512i sum3,
        __m128i bias) {

      __m512i sum = m512_hadd128x16_interleave(sum0, sum1, sum2, sum3);

      __m256i sum256lo = _mm512_castsi512_si256(sum);
      __m256i sum256hi = _mm512_extracti64x4_epi64(sum, 1);

      sum256lo = _mm256_add_epi32(sum256lo, sum256hi);

      __m128i sum128lo = _mm256_castsi256_si128(sum256lo);
      __m128i sum128hi = _mm256_extracti128_si256(sum256lo, 1);

      return _mm_add_epi32(_mm_add_epi32(sum128lo, sum128hi), bias);
    }

    [[maybe_unused]] static void m512_add_dpbusd_epi32(
        __m512i& acc,
        __m512i a,
        __m512i b) {

# if defined (USE_VNNI)
#   if defined (USE_INLINE_ASM)
      asm(
        "vpdpbusd %[b], %[a], %[acc]\n\t"
        : [acc]"+v"(acc)
        : [a]"v"(a), [b]"vm"(b)
      );
#   else
      acc = _mm512_dpbusd_epi32(acc, a, b);
#   endif
# else
#   if defined (USE_INLINE_ASM)
      __m512i tmp = _mm512_maddubs_epi16(a, b);
      asm(
          "vpmaddwd    %[tmp], %[ones], %[tmp]\n\t"
          "vpaddd      %[acc], %[tmp], %[acc]\n\t"
          : [acc]"+v"(acc), [tmp]"+&v"(tmp)
          : [ones]"v"(_mm512_set1_epi16(1))
      );
#   else
      __m512i product0 = _mm512_maddubs_epi16(a, b);
      product0 = _mm512_madd_epi16(product0, _mm512_set1_epi16(1));
      acc = _mm512_add_epi32(acc, product0);
#   endif
# endif
    }

    [[maybe_unused]] static void m512_add_dpbusd_epi32x2(
        __m512i& acc,
        __m512i a0, __m512i b0,
        __m512i a1, __m512i b1) {

# if defined (USE_VNNI)
#   if defined (USE_INLINE_ASM)
      asm(
        "vpdpbusd %[b0], %[a0], %[acc]\n\t"
        "vpdpbusd %[b1], %[a1], %[acc]\n\t"
        : [acc]"+v"(acc)
        : [a0]"v"(a0), [b0]"vm"(b0), [a1]"v"(a1), [b1]"vm"(b1)
      );
#   else
      acc = _mm512_dpbusd_epi32(acc, a0, b0);
      acc = _mm512_dpbusd_epi32(acc, a1, b1);
#   endif
# else
#   if defined (USE_INLINE_ASM)
      __m512i tmp0 = _mm512_maddubs_epi16(a0, b0);
      __m512i tmp1 = _mm512_maddubs_epi16(a1, b1);
      asm(
          "vpaddsw     %[tmp0], %[tmp1], %[tmp0]\n\t"
          "vpmaddwd    %[tmp0], %[ones], %[tmp0]\n\t"
          "vpaddd      %[acc], %[tmp0], %[acc]\n\t"
          : [acc]"+v"(acc), [tmp0]"+&v"(tmp0)
          : [tmp1]"v"(tmp1), [ones]"v"(_mm512_set1_epi16(1))
      );
#   else
      __m512i product0 = _mm512_maddubs_epi16(a0, b0);
      __m512i product1 = _mm512_maddubs_epi16(a1, b1);
      product0 = _mm512_adds_epi16(product0, product1);
      product0 = _mm512_madd_epi16(product0, _mm512_set1_epi16(1));
      acc = _mm512_add_epi32(acc, product0);
#   endif
# endif
    }

#endif

#if defined (USE_AVX2)

    [[maybe_unused]] static int m256_hadd(__m256i sum, int bias) {
      __m128i sum128 = _mm_add_epi32(_mm256_castsi256_si128(sum), _mm256_extracti128_si256(sum, 1));
      sum128 = _mm_add_epi32(sum128, _mm_shuffle_epi32(sum128, _MM_PERM_BADC));
      sum128 = _mm_add_epi32(sum128, _mm_shuffle_epi32(sum128, _MM_PERM_CDAB));
      return _mm_cvtsi128_si32(sum128) + bias;
    }

    [[maybe_unused]] static __m128i m256_haddx4(
        __m256i sum0, __m256i sum1, __m256i sum2, __m256i sum3,
        __m128i bias) {

      sum0 = _mm256_hadd_epi32(sum0, sum1);
      sum2 = _mm256_hadd_epi32(sum2, sum3);

      sum0 = _mm256_hadd_epi32(sum0, sum2);

      __m128i sum128lo = _mm256_castsi256_si128(sum0);
      __m128i sum128hi = _mm256_extracti128_si256(sum0, 1);

      return _mm_add_epi32(_mm_add_epi32(sum128lo, sum128hi), bias);
    }

    [[maybe_unused]] static void m256_add_dpbusd_epi32(
        __m256i& acc,
        __m256i a,
        __m256i b) {

# if defined (USE_VNNI)
#   if defined (USE_INLINE_ASM)
      asm(
        VNNI_PREFIX "vpdpbusd %[b], %[a], %[acc]\n\t"
        : [acc]"+v"(acc)
        : [a]"v"(a), [b]"vm"(b)
      );
#   else
      acc = _mm256_dpbusd_epi32(acc, a, b);
#   endif
# else
#   if defined (USE_INLINE_ASM)
      __m256i tmp = _mm256_maddubs_epi16(a, b);
      asm(
          "vpmaddwd    %[tmp], %[ones], %[tmp]\n\t"
          "vpaddd      %[acc], %[tmp], %[acc]\n\t"
          : [acc]"+v"(acc), [tmp]"+&v"(tmp)
          : [ones]"v"(_mm256_set1_epi16(1))
      );
#   else
      __m256i product0 = _mm256_maddubs_epi16(a, b);
      product0 = _mm256_madd_epi16(product0, _mm256_set1_epi16(1));
      acc = _mm256_add_epi32(acc, product0);
#   endif
# endif
    }

    [[maybe_unused]] static void m256_add_dpbusd_epi32x2(
        __m256i& acc,
        __m256i a0, __m256i b0,
        __m256i a1, __m256i b1) {

# if defined (USE_VNNI)
#   if defined (USE_INLINE_ASM)
      asm(
        VNNI_PREFIX "vpdpbusd %[b0], %[a0], %[acc]\n\t"
        VNNI_PREFIX "vpdpbusd %[b1], %[a1], %[acc]\n\t"
        : [acc]"+v"(acc)
        : [a0]"v"(a0), [b0]"vm"(b0), [a1]"v"(a1), [b1]"vm"(b1)
      );
#   else
      acc = _mm256_dpbusd_epi32(acc, a0, b0);
      acc = _mm256_dpbusd_epi32(acc, a1, b1);
#   endif
# else
#   if defined (USE_INLINE_ASM)
      __m256i tmp0 = _mm256_maddubs_epi16(a0, b0);
      __m256i tmp1 = _mm256_maddubs_epi16(a1, b1);
      asm(
          "vpaddsw     %[tmp0], %[tmp1], %[tmp0]\n\t"
          "vpmaddwd    %[tmp0], %[ones], %[tmp0]\n\t"
          "vpaddd      %[acc], %[tmp0], %[acc]\n\t"
          : [acc]"+v"(acc), [tmp0]"+&v"(tmp0)
          : [tmp1]"v"(tmp1), [ones]"v"(_mm256_set1_epi16(1))
      );
#   else
      __m256i product0 = _mm256_maddubs_epi16(a0, b0);
      __m256i product1 = _mm256_maddubs_epi16(a1, b1);
      product0 = _mm256_adds_epi16(product0, product1);
      product0 = _mm256_madd_epi16(product0, _mm256_set1_epi16(1));
      acc = _mm256_add_epi32(acc, product0);
#   endif
# endif
    }

#endif

#if defined (USE_SSSE3)

    [[maybe_unused]] static int m128_hadd(__m128i sum, int bias) {
      sum = _mm_add_epi32(sum, _mm_shuffle_epi32(sum, 0x4E)); //_MM_PERM_BADC
      sum = _mm_add_epi32(sum, _mm_shuffle_epi32(sum, 0xB1)); //_MM_PERM_CDAB
      return _mm_cvtsi128_si32(sum) + bias;
    }

    [[maybe_unused]] static __m128i m128_haddx4(
        __m128i sum0, __m128i sum1, __m128i sum2, __m128i sum3,
        __m128i bias) {

      sum0 = _mm_hadd_epi32(sum0, sum1);
      sum2 = _mm_hadd_epi32(sum2, sum3);
      sum0 = _mm_hadd_epi32(sum0, sum2);
      return _mm_add_epi32(sum0, bias);
    }

    [[maybe_unused]] static void m128_add_dpbusd_epi32(
        __m128i& acc,
        __m128i a,
        __m128i b) {

#   if defined (USE_INLINE_ASM)
      __m128i tmp = _mm_maddubs_epi16(a, b);
      asm(
          "pmaddwd    %[ones], %[tmp]\n\t"
          "paddd      %[tmp], %[acc]\n\t"
          : [acc]"+v"(acc), [tmp]"+&v"(tmp)
          : [ones]"v"(_mm_set1_epi16(1))
      );
#   else
      __m128i product0 = _mm_maddubs_epi16(a, b);
      product0 = _mm_madd_epi16(product0, _mm_set1_epi16(1));
      acc = _mm_add_epi32(acc, product0);
#   endif
    }

    [[maybe_unused]] static void m128_add_dpbusd_epi32x2(
        __m128i& acc,
        __m128i a0, __m128i b0,
        __m128i a1, __m128i b1) {

#   if defined (USE_INLINE_ASM)
      __m128i tmp0 = _mm_maddubs_epi16(a0, b0);
      __m128i tmp1 = _mm_maddubs_epi16(a1, b1);
      asm(
          "paddsw     %[tmp1], %[tmp0]\n\t"
          "pmaddwd    %[ones], %[tmp0]\n\t"
          "paddd      %[tmp0], %[acc]\n\t"
          : [acc]"+v"(acc), [tmp0]"+&v"(tmp0)
          : [tmp1]"v"(tmp1), [ones]"v"(_mm_set1_epi16(1))
      );
#   else
      __m128i product0 = _mm_maddubs_epi16(a0, b0);
      __m128i product1 = _mm_maddubs_epi16(a1, b1);
      product0 = _mm_adds_epi16(product0, product1);
      product0 = _mm_madd_epi16(product0, _mm_set1_epi16(1));
      acc = _mm_add_epi32(acc, product0);
#   endif
    }

#endif

#if defined (USE_NEON)

    [[maybe_unused]] static int neon_m128_reduce_add_epi32(int32x4_t s) {
#   if USE_NEON >= 8
      return vaddvq_s32(s);
#   else
      return s[0] + s[1] + s[2] + s[3];
#   endif
    }

    [[maybe_unused]] static int neon_m128_hadd(int32x4_t sum, int bias) {
      return neon_m128_reduce_add_epi32(sum) + bias;
    }

    [[maybe_unused]] static int32x4_t neon_m128_haddx4(
        int32x4_t sum0, int32x4_t sum1, int32x4_t sum2, int32x4_t sum3,
        int32x4_t bias) {

      int32x4_t hsums {
        neon_m128_reduce_add_epi32(sum0),
        neon_m128_reduce_add_epi32(sum1),
        neon_m128_reduce_add_epi32(sum2),
        neon_m128_reduce_add_epi32(sum3)
      };
      return vaddq_s32(hsums, bias);
    }

    [[maybe_unused]] static void neon_m128_add_dpbusd_epi32x2(
        int32x4_t& acc,
        int8x8_t a0, int8x8_t b0,
        int8x8_t a1, int8x8_t b1) {

      int16x8_t product = vmull_s8(a0, b0);
      product = vmlal_s8(product, a1, b1);
      acc = vpadalq_s16(acc, product);
    }

#endif

}

#endif // STOCKFISH_SIMD_H_INCLUDED