/******************************************************************************
 * Project:  GDAL
 * Purpose:  AVX2 emulation with SSE2 + a few SSE4.1 emulation
 * Author:   Even Rouault <even dot rouault at spatialys dot com>
 *
 ******************************************************************************
 * Copyright (c) 2016, Even Rouault <even dot rouault at spatialys dot com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#ifndef GDAL_AVX2_EMULATION_H_INCLUDED
#define GDAL_AVX2_EMULATION_H_INCLUDED

#include <emmintrin.h>

#ifdef __SSE4_1__
#include <smmintrin.h>

#define GDALmm_min_epu16 _mm_min_epu16
#define GDALmm_max_epu16 _mm_max_epu16
#define GDALmm_mullo_epi32 _mm_mullo_epi32
#define GDALmm_cvtepu8_epi16 _mm_cvtepu8_epi16
#define GDALmm_cvtepu16_epi32 _mm_cvtepu16_epi32
#define GDALmm_cvtepu16_epi64 _mm_cvtepu16_epi64
#define GDALmm_cvtepu32_epi64 _mm_cvtepu32_epi64

#else
// Emulation of SSE4.1 _mm_min_epu16 and _mm_max_epu16 with SSE2 only

static inline __m128i GDALAVX2Emul_mm_cmple_epu16(__m128i x, __m128i y)
{
    return _mm_cmpeq_epi16(_mm_subs_epu16(x, y), _mm_setzero_si128());
}

static inline __m128i GDALAVX2Emul_mm_ternary(__m128i mask, __m128i then_reg,
                                              __m128i else_reg)
{
    return _mm_or_si128(_mm_and_si128(mask, then_reg),
                        _mm_andnot_si128(mask, else_reg));
}

static inline __m128i GDALmm_min_epu16(__m128i x, __m128i y)
{
    const __m128i mask = GDALAVX2Emul_mm_cmple_epu16(x, y);
    return GDALAVX2Emul_mm_ternary(mask, x, y);
}

static inline __m128i GDALmm_max_epu16(__m128i x, __m128i y)
{
    const __m128i mask = GDALAVX2Emul_mm_cmple_epu16(x, y);
    return GDALAVX2Emul_mm_ternary(mask, y, x);
}

static inline __m128i GDALmm_mullo_epi32(__m128i x, __m128i y)
{
    const __m128i mul02 = _mm_shuffle_epi32(_mm_mul_epu32(x, y), 2 << 2);
    const __m128i mul13 = _mm_shuffle_epi32(
        _mm_mul_epu32(_mm_srli_si128(x, 4), _mm_srli_si128(y, 4)), 2 << 2);
    return _mm_unpacklo_epi32(mul02, mul13);
    ;
}

static inline __m128i GDALmm_cvtepu8_epi16(__m128i x)
{
    return _mm_unpacklo_epi8(x, _mm_setzero_si128());
}

static inline __m128i GDALmm_cvtepu16_epi32(__m128i x)
{
    return _mm_unpacklo_epi16(x, _mm_setzero_si128());
}

static inline __m128i GDALmm_cvtepu16_epi64(__m128i x)
{
    return _mm_unpacklo_epi32(_mm_unpacklo_epi16(x, _mm_setzero_si128()),
                              _mm_setzero_si128());
}

static inline __m128i GDALmm_cvtepu32_epi64(__m128i x)
{
    return _mm_unpacklo_epi32(x, _mm_setzero_si128());
}

#endif  // __SSE4_1__

#ifdef __AVX2__

#include <immintrin.h>

typedef __m256i GDALm256i;

#define GDALmm256_set1_epi8 _mm256_set1_epi8
#define GDALmm256_set1_epi16 _mm256_set1_epi16
#define GDALmm256_set1_epi32 _mm256_set1_epi32
#define GDALmm256_setzero_si256 _mm256_setzero_si256
#define GDALmm256_load_si256 _mm256_load_si256
#define GDALmm256_store_si256 _mm256_store_si256
#define GDALmm256_storeu_si256 _mm256_storeu_si256
#define GDALmm256_cmpeq_epi8 _mm256_cmpeq_epi8
#define GDALmm256_sad_epu8 _mm256_sad_epu8
#define GDALmm256_add_epi32 _mm256_add_epi32
#define GDALmm256_andnot_si256 _mm256_andnot_si256
#define GDALmm256_and_si256 _mm256_and_si256
#define GDALmm256_or_si256 _mm256_or_si256
#define GDALmm256_min_epu8 _mm256_min_epu8
#define GDALmm256_max_epu8 _mm256_max_epu8
#define GDALmm256_extracti128_si256 _mm256_extracti128_si256
#define GDALmm256_cvtepu8_epi16 _mm256_cvtepu8_epi16
#define GDALmm256_madd_epi16 _mm256_madd_epi16
#define GDALmm256_min_epu16 _mm256_min_epu16
#define GDALmm256_max_epu16 _mm256_max_epu16
#define GDALmm256_cvtepu16_epi32 _mm256_cvtepu16_epi32
#define GDALmm256_cvtepu16_epi64 _mm256_cvtepu16_epi64
#define GDALmm256_cvtepu32_epi64 _mm256_cvtepu32_epi64
#define GDALmm256_mullo_epi32 _mm256_mullo_epi32
#define GDALmm256_add_epi64 _mm256_add_epi64
#define GDALmm256_add_epi16 _mm256_add_epi16
#define GDALmm256_sub_epi16 _mm256_sub_epi16
#define GDALmm256_min_epi16 _mm256_min_epi16
#define GDALmm256_max_epi16 _mm256_max_epi16
#define GDALmm256_srli_epi16 _mm256_srli_epi16
#define GDALmm256_srli_epi32 _mm256_srli_epi32
#define GDALmm256_srli_epi64 _mm256_srli_epi64
#define GDALmm256_set1_epi64x _mm256_set1_epi64x

#else

typedef struct
{
    __m128i low;
    __m128i high;
} GDALm256i;

static inline GDALm256i GDALmm256_set1_epi8(char c)
{
    GDALm256i reg;
    reg.low = _mm_set1_epi8(c);
    reg.high = _mm_set1_epi8(c);
    return reg;
}

static inline GDALm256i GDALmm256_set1_epi16(short s)
{
    GDALm256i reg;
    reg.low = _mm_set1_epi16(s);
    reg.high = _mm_set1_epi16(s);
    return reg;
}

static inline GDALm256i GDALmm256_set1_epi32(int i)
{
    GDALm256i reg;
    reg.low = _mm_set1_epi32(i);
    reg.high = _mm_set1_epi32(i);
    return reg;
}

static inline GDALm256i GDALmm256_set1_epi64x(long long i)
{
    GDALm256i reg;
    reg.low = _mm_set1_epi64x(i);
    reg.high = _mm_set1_epi64x(i);
    return reg;
}

static inline GDALm256i GDALmm256_setzero_si256()
{
    GDALm256i reg;
    reg.low = _mm_setzero_si128();
    reg.high = _mm_setzero_si128();
    return reg;
}

static inline GDALm256i GDALmm256_load_si256(GDALm256i const *p)
{
    GDALm256i reg;
    reg.low = _mm_load_si128(reinterpret_cast<__m128i const *>(p));
    reg.high = _mm_load_si128(reinterpret_cast<__m128i const *>(
        reinterpret_cast<const char *>(p) + 16));
    return reg;
}

static inline void GDALmm256_store_si256(GDALm256i *p, GDALm256i reg)
{
    _mm_store_si128(reinterpret_cast<__m128i *>(p), reg.low);
    _mm_store_si128(
        reinterpret_cast<__m128i *>(reinterpret_cast<char *>(p) + 16),
        reg.high);
}

static inline void GDALmm256_storeu_si256(GDALm256i *p, GDALm256i reg)
{
    _mm_storeu_si128(reinterpret_cast<__m128i *>(p), reg.low);
    _mm_storeu_si128(
        reinterpret_cast<__m128i *>(reinterpret_cast<char *>(p) + 16),
        reg.high);
}

#define DEFINE_BINARY_MM256(mm256name, mm128name)                              \
    static inline GDALm256i mm256name(GDALm256i r1, GDALm256i r2)              \
    {                                                                          \
        GDALm256i reg;                                                         \
        reg.low = mm128name(r1.low, r2.low);                                   \
        reg.high = mm128name(r1.high, r2.high);                                \
        return reg;                                                            \
    }

DEFINE_BINARY_MM256(GDALmm256_cmpeq_epi8, _mm_cmpeq_epi8)
DEFINE_BINARY_MM256(GDALmm256_sad_epu8, _mm_sad_epu8)
DEFINE_BINARY_MM256(GDALmm256_add_epi32, _mm_add_epi32)
DEFINE_BINARY_MM256(GDALmm256_andnot_si256, _mm_andnot_si128)
DEFINE_BINARY_MM256(GDALmm256_and_si256, _mm_and_si128)
DEFINE_BINARY_MM256(GDALmm256_or_si256, _mm_or_si128)
DEFINE_BINARY_MM256(GDALmm256_min_epu8, _mm_min_epu8)
DEFINE_BINARY_MM256(GDALmm256_max_epu8, _mm_max_epu8)
DEFINE_BINARY_MM256(GDALmm256_madd_epi16, _mm_madd_epi16)
DEFINE_BINARY_MM256(GDALmm256_min_epu16, GDALmm_min_epu16)
DEFINE_BINARY_MM256(GDALmm256_max_epu16, GDALmm_max_epu16)
DEFINE_BINARY_MM256(GDALmm256_mullo_epi32, GDALmm_mullo_epi32)
DEFINE_BINARY_MM256(GDALmm256_add_epi64, _mm_add_epi64)
DEFINE_BINARY_MM256(GDALmm256_add_epi16, _mm_add_epi16)
DEFINE_BINARY_MM256(GDALmm256_sub_epi16, _mm_sub_epi16)
DEFINE_BINARY_MM256(GDALmm256_min_epi16, _mm_min_epi16)
DEFINE_BINARY_MM256(GDALmm256_max_epi16, _mm_max_epi16)

static inline __m128i GDALmm256_extracti128_si256(GDALm256i reg, int index)
{
    return (index == 0) ? reg.low : reg.high;
}

#define DEFINE_CVTE_MM256(mm256name, mm128name)                                \
    static inline GDALm256i mm256name(__m128i x)                               \
    {                                                                          \
        GDALm256i reg;                                                         \
        reg.low = mm128name(x);                                                \
        reg.high = mm128name(_mm_srli_si128(x, 8));                            \
        return reg;                                                            \
    }

DEFINE_CVTE_MM256(GDALmm256_cvtepu8_epi16, GDALmm_cvtepu8_epi16)
DEFINE_CVTE_MM256(GDALmm256_cvtepu16_epi32, GDALmm_cvtepu16_epi32)
DEFINE_CVTE_MM256(GDALmm256_cvtepu16_epi64, GDALmm_cvtepu16_epi64)
DEFINE_CVTE_MM256(GDALmm256_cvtepu32_epi64, GDALmm_cvtepu32_epi64)

static inline GDALm256i GDALmm256_srli_epi16(GDALm256i reg, int imm)
{
    GDALm256i ret;
    ret.low = _mm_srli_epi16(reg.low, imm);
    ret.high = _mm_srli_epi16(reg.high, imm);
    return ret;
}

static inline GDALm256i GDALmm256_srli_epi32(GDALm256i reg, int imm)
{
    GDALm256i ret;
    ret.low = _mm_srli_epi32(reg.low, imm);
    ret.high = _mm_srli_epi32(reg.high, imm);
    return ret;
}

static inline GDALm256i GDALmm256_srli_epi64(GDALm256i reg, int imm)
{
    GDALm256i ret;
    ret.low = _mm_srli_epi64(reg.low, imm);
    ret.high = _mm_srli_epi64(reg.high, imm);
    return ret;
}

#endif

#endif /* GDAL_AVX2_EMULATION_H_INCLUDED */
