/**
 *  @brief SIMD-accelerated MaxSim (ColBERT late-interaction) for Ice Lake.
 *  @file include/numkong/maxsim/icelake.h
 *  @author Ash Vardanian
 *  @date February 28, 2026
 *
 *  @sa include/numkong/maxsim.h
 *
 *  Uses AVX-512 VNNI (VPDPBUSD) for coarse i8 screening. The coarse argmax kernel and reduce helper
 *  are shared with genoa.h — genoa.h imports them from this file for its bf16 compute path.
 *
 *  VPDPBUSD computes 4 groups of (u8 × i8) → i32 per 128-bit lane, processing 64 i8 pairs
 *  per ZMM register operation. Bias correction via XOR with 0x80 converts signed queries
 *  to unsigned, then subtracts 128 * sum(document_i8) after the depth loop.
 *
 *  4x4 register tiling: 4 queries × 4 documents = 16 ZMM accumulators per depth loop.
 *  Each document load is amortized across 4 VPDPBUSDs, and each query load across 4 documents.
 *
 *      Intrinsic            Instruction  Icelake   Genoa
 *      _mm512_dpbusd_epi32  VPDPBUSD     5cy @ p0  4cy @ p01
 */
#ifndef NK_MAXSIM_ICELAKE_H
#define NK_MAXSIM_ICELAKE_H

#if NK_TARGET_X86_
#if NK_TARGET_ICELAKE

#include "numkong/types.h"
#include "numkong/maxsim/serial.h"   // `nk_maxsim_packed_header_t`
#include "numkong/dot.h"             // `nk_dot_f32`, `nk_dot_f16`
#include "numkong/cast/haswell.h"    // `nk_f16_to_f32_haswell`
#include "numkong/spatial/haswell.h" // `nk_f32_sqrt_haswell`

#if defined(__cplusplus)
extern "C" {
#endif

#if defined(__clang__)
#pragma clang attribute push(                                                                        \
    __attribute__((target("avx2,avx512f,avx512vl,avx512bw,avx512dq,avx512vnni,f16c,fma,bmi,bmi2"))), \
    apply_to = function)
#elif defined(__GNUC__)
#pragma GCC push_options
#pragma GCC target("avx2", "avx512f", "avx512vl", "avx512bw", "avx512dq", "avx512vnni", "f16c", "fma", "bmi", "bmi2")
#endif

#pragma region Single Precision Floats

NK_PUBLIC nk_size_t nk_maxsim_packed_size_f32_icelake(nk_size_t vector_count, nk_size_t depth) {
    return nk_maxsim_packed_size_(vector_count, depth, sizeof(nk_f32_t), 64);
}

NK_PUBLIC void nk_maxsim_pack_f32_icelake( //
    nk_f32_t const *vectors, nk_size_t vector_count, nk_size_t depth, nk_size_t stride_in_bytes, void *packed) {

    nk_size_t const element_bytes = sizeof(nk_f32_t);
    nk_size_t depth_i8_padded = nk_maxsim_packed_header_setup_(packed, vector_count, depth, 64, element_bytes);

    nk_maxsim_packed_header_t const *header = (nk_maxsim_packed_header_t const *)packed;
    nk_i8_t *quantized_i8 = (nk_i8_t *)((char *)packed + header->offset_i8_data);
    nk_maxsim_vector_metadata_t *metadata = (nk_maxsim_vector_metadata_t *)((char *)packed + header->offset_metadata);
    char *originals = (char *)packed + header->offset_original_data;
    nk_size_t const original_stride = header->original_stride_bytes;

    for (nk_size_t vector_index = 0; vector_index < vector_count; vector_index++) {
        char const *source_row = (char const *)vectors + vector_index * stride_in_bytes;
        nk_f32_t norm_sq;
        nk_maxsim_quantize_vector_(source_row, element_bytes, depth, depth_i8_padded, 127.0f, nk_f32_to_f32_,
                                   &quantized_i8[vector_index * depth_i8_padded], &metadata[vector_index], &norm_sq);
        metadata[vector_index].inverse_norm_f32 = norm_sq > 0.0f ? (1.0f / nk_f32_sqrt_haswell(norm_sq)) : 0.0f;
        char *destination_original = originals + vector_index * original_stride;
        nk_copy_bytes_(destination_original, source_row, depth * element_bytes);
        for (nk_size_t byte_index = depth * element_bytes; byte_index < original_stride; byte_index++)
            destination_original[byte_index] = 0;
    }
}

#pragma endregion

#pragma region Half Precision Floats

NK_PUBLIC nk_size_t nk_maxsim_packed_size_f16_icelake(nk_size_t vector_count, nk_size_t depth) {
    return nk_maxsim_packed_size_(vector_count, depth, sizeof(nk_f16_t), 64);
}

NK_PUBLIC void nk_maxsim_pack_f16_icelake( //
    nk_f16_t const *vectors, nk_size_t vector_count, nk_size_t depth, nk_size_t stride_in_bytes, void *packed) {

    nk_size_t const element_bytes = sizeof(nk_f16_t);
    nk_size_t depth_i8_padded = nk_maxsim_packed_header_setup_(packed, vector_count, depth, 64, element_bytes);

    nk_maxsim_packed_header_t const *header = (nk_maxsim_packed_header_t const *)packed;
    nk_i8_t *quantized_i8 = (nk_i8_t *)((char *)packed + header->offset_i8_data);
    nk_maxsim_vector_metadata_t *metadata = (nk_maxsim_vector_metadata_t *)((char *)packed + header->offset_metadata);
    char *originals = (char *)packed + header->offset_original_data;
    nk_size_t const original_stride = header->original_stride_bytes;

    for (nk_size_t vector_index = 0; vector_index < vector_count; vector_index++) {
        char const *source_row = (char const *)vectors + vector_index * stride_in_bytes;
        nk_f32_t norm_sq;
        nk_maxsim_quantize_vector_(source_row, element_bytes, depth, depth_i8_padded, 127.0f,
                                   (nk_maxsim_to_f32_t)nk_f16_to_f32_haswell,
                                   &quantized_i8[vector_index * depth_i8_padded], &metadata[vector_index], &norm_sq);
        metadata[vector_index].inverse_norm_f32 = norm_sq > 0.0f ? (1.0f / nk_f32_sqrt_haswell(norm_sq)) : 0.0f;
        char *destination_original = originals + vector_index * original_stride;
        nk_copy_bytes_(destination_original, source_row, depth * element_bytes);
        for (nk_size_t byte_index = depth * element_bytes; byte_index < original_stride; byte_index++)
            destination_original[byte_index] = 0;
    }
}

#pragma endregion

#pragma region Coarse Argmax

/** @brief Reduces 4 ZMM i32x16 accumulators to a single __m128i with 4 horizontal sums. */
NK_INTERNAL __m128i nk_maxsim_reduce_i32x16x4_icelake_(         //
    __m512i accumulator_a_i32x16, __m512i accumulator_b_i32x16, //
    __m512i accumulator_c_i32x16, __m512i accumulator_d_i32x16) {
    // Step 1: 16 → 8 (extract high 256-bit half and add to low half)
    __m256i sum_a_i32x8 = _mm256_add_epi32(_mm512_castsi512_si256(accumulator_a_i32x16),
                                           _mm512_extracti32x8_epi32(accumulator_a_i32x16, 1));
    __m256i sum_b_i32x8 = _mm256_add_epi32(_mm512_castsi512_si256(accumulator_b_i32x16),
                                           _mm512_extracti32x8_epi32(accumulator_b_i32x16, 1));
    __m256i sum_c_i32x8 = _mm256_add_epi32(_mm512_castsi512_si256(accumulator_c_i32x16),
                                           _mm512_extracti32x8_epi32(accumulator_c_i32x16, 1));
    __m256i sum_d_i32x8 = _mm256_add_epi32(_mm512_castsi512_si256(accumulator_d_i32x16),
                                           _mm512_extracti32x8_epi32(accumulator_d_i32x16, 1));
    // Step 2: 8 → 4 (extract high 128-bit half and add to low half)
    __m128i sum_a_i32x4 = _mm_add_epi32(_mm256_castsi256_si128(sum_a_i32x8), _mm256_extracti128_si256(sum_a_i32x8, 1));
    __m128i sum_b_i32x4 = _mm_add_epi32(_mm256_castsi256_si128(sum_b_i32x8), _mm256_extracti128_si256(sum_b_i32x8, 1));
    __m128i sum_c_i32x4 = _mm_add_epi32(_mm256_castsi256_si128(sum_c_i32x8), _mm256_extracti128_si256(sum_c_i32x8, 1));
    __m128i sum_d_i32x4 = _mm_add_epi32(_mm256_castsi256_si128(sum_d_i32x8), _mm256_extracti128_si256(sum_d_i32x8, 1));
    // Step 3: 4x4 transpose + reduce → [sum_a, sum_b, sum_c, sum_d]
    __m128i transpose_ab_low_i32x4 = _mm_unpacklo_epi32(sum_a_i32x4, sum_b_i32x4);
    __m128i transpose_cd_low_i32x4 = _mm_unpacklo_epi32(sum_c_i32x4, sum_d_i32x4);
    __m128i transpose_ab_high_i32x4 = _mm_unpackhi_epi32(sum_a_i32x4, sum_b_i32x4);
    __m128i transpose_cd_high_i32x4 = _mm_unpackhi_epi32(sum_c_i32x4, sum_d_i32x4);
    __m128i sum_lane_0_i32x4 = _mm_unpacklo_epi64(transpose_ab_low_i32x4, transpose_cd_low_i32x4);
    __m128i sum_lane_1_i32x4 = _mm_unpackhi_epi64(transpose_ab_low_i32x4, transpose_cd_low_i32x4);
    __m128i sum_lane_2_i32x4 = _mm_unpacklo_epi64(transpose_ab_high_i32x4, transpose_cd_high_i32x4);
    __m128i sum_lane_3_i32x4 = _mm_unpackhi_epi64(transpose_ab_high_i32x4, transpose_cd_high_i32x4);
    return _mm_add_epi32(_mm_add_epi32(sum_lane_0_i32x4, sum_lane_1_i32x4),
                         _mm_add_epi32(sum_lane_2_i32x4, sum_lane_3_i32x4));
}

/**
 *  @brief Factored coarse i8 argmax kernel for Ice Lake / Genoa.
 *  Uses AVX-512 VNNI VPDPBUSD with XOR-0x80 bias and 128*sum_quantized correction.
 */
NK_INTERNAL void nk_maxsim_coarse_argmax_icelake_(        //
    nk_i8_t const *query_i8, nk_i8_t const *document_i8,  //
    nk_maxsim_vector_metadata_t const *document_metadata, //
    nk_size_t query_count, nk_size_t document_count,      //
    nk_size_t depth_i8_padded, nk_u32_t *best_document_indices) {

    __m512i const xor_mask_u8x64 = _mm512_set1_epi8((char)0x80);

    // Primary path: 4-query grouping
    nk_size_t query_block_start_index = 0;
    for (; query_block_start_index + 4 <= query_count; query_block_start_index += 4) {
        __m128i running_max_i32x4 = _mm_set1_epi32(NK_I32_MIN);
        __m128i running_argmax_i32x4 = _mm_setzero_si128();

        // 4x4 document blocking
        nk_size_t document_block_start_index = 0;
        for (; document_block_start_index + 4 <= document_count; document_block_start_index += 4) {
            __m512i accumulator_tiles_i32x16[4][4];
            for (nk_size_t query_tile_index = 0; query_tile_index < 4; query_tile_index++)
                for (nk_size_t document_tile_index = 0; document_tile_index < 4; document_tile_index++)
                    accumulator_tiles_i32x16[query_tile_index][document_tile_index] = _mm512_setzero_si512();

            for (nk_size_t depth_index = 0; depth_index < depth_i8_padded; depth_index += 64) {
                __m512i query_biased_u8x64_0 = _mm512_xor_si512(
                    _mm512_loadu_si512(
                        (__m512i const *)(query_i8 + (query_block_start_index + 0) * depth_i8_padded + depth_index)),
                    xor_mask_u8x64);
                __m512i query_biased_u8x64_1 = _mm512_xor_si512(
                    _mm512_loadu_si512(
                        (__m512i const *)(query_i8 + (query_block_start_index + 1) * depth_i8_padded + depth_index)),
                    xor_mask_u8x64);
                __m512i query_biased_u8x64_2 = _mm512_xor_si512(
                    _mm512_loadu_si512(
                        (__m512i const *)(query_i8 + (query_block_start_index + 2) * depth_i8_padded + depth_index)),
                    xor_mask_u8x64);
                __m512i query_biased_u8x64_3 = _mm512_xor_si512(
                    _mm512_loadu_si512(
                        (__m512i const *)(query_i8 + (query_block_start_index + 3) * depth_i8_padded + depth_index)),
                    xor_mask_u8x64);

                __m512i document_i8x64;

                document_i8x64 = _mm512_loadu_si512(
                    (__m512i const *)(document_i8 + (document_block_start_index + 0) * depth_i8_padded + depth_index));
                accumulator_tiles_i32x16[0][0] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[0][0],
                                                                     query_biased_u8x64_0, document_i8x64);
                accumulator_tiles_i32x16[1][0] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[1][0],
                                                                     query_biased_u8x64_1, document_i8x64);
                accumulator_tiles_i32x16[2][0] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[2][0],
                                                                     query_biased_u8x64_2, document_i8x64);
                accumulator_tiles_i32x16[3][0] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[3][0],
                                                                     query_biased_u8x64_3, document_i8x64);

                document_i8x64 = _mm512_loadu_si512(
                    (__m512i const *)(document_i8 + (document_block_start_index + 1) * depth_i8_padded + depth_index));
                accumulator_tiles_i32x16[0][1] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[0][1],
                                                                     query_biased_u8x64_0, document_i8x64);
                accumulator_tiles_i32x16[1][1] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[1][1],
                                                                     query_biased_u8x64_1, document_i8x64);
                accumulator_tiles_i32x16[2][1] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[2][1],
                                                                     query_biased_u8x64_2, document_i8x64);
                accumulator_tiles_i32x16[3][1] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[3][1],
                                                                     query_biased_u8x64_3, document_i8x64);

                document_i8x64 = _mm512_loadu_si512(
                    (__m512i const *)(document_i8 + (document_block_start_index + 2) * depth_i8_padded + depth_index));
                accumulator_tiles_i32x16[0][2] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[0][2],
                                                                     query_biased_u8x64_0, document_i8x64);
                accumulator_tiles_i32x16[1][2] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[1][2],
                                                                     query_biased_u8x64_1, document_i8x64);
                accumulator_tiles_i32x16[2][2] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[2][2],
                                                                     query_biased_u8x64_2, document_i8x64);
                accumulator_tiles_i32x16[3][2] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[3][2],
                                                                     query_biased_u8x64_3, document_i8x64);

                document_i8x64 = _mm512_loadu_si512(
                    (__m512i const *)(document_i8 + (document_block_start_index + 3) * depth_i8_padded + depth_index));
                accumulator_tiles_i32x16[0][3] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[0][3],
                                                                     query_biased_u8x64_0, document_i8x64);
                accumulator_tiles_i32x16[1][3] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[1][3],
                                                                     query_biased_u8x64_1, document_i8x64);
                accumulator_tiles_i32x16[2][3] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[2][3],
                                                                     query_biased_u8x64_2, document_i8x64);
                accumulator_tiles_i32x16[3][3] = _mm512_dpbusd_epi32(accumulator_tiles_i32x16[3][3],
                                                                     query_biased_u8x64_3, document_i8x64);
            }

            __m128i query_0_coarse_dots_i32x4 = nk_maxsim_reduce_i32x16x4_icelake_(
                accumulator_tiles_i32x16[0][0], accumulator_tiles_i32x16[0][1], accumulator_tiles_i32x16[0][2],
                accumulator_tiles_i32x16[0][3]);
            __m128i query_1_coarse_dots_i32x4 = nk_maxsim_reduce_i32x16x4_icelake_(
                accumulator_tiles_i32x16[1][0], accumulator_tiles_i32x16[1][1], accumulator_tiles_i32x16[1][2],
                accumulator_tiles_i32x16[1][3]);
            __m128i query_2_coarse_dots_i32x4 = nk_maxsim_reduce_i32x16x4_icelake_(
                accumulator_tiles_i32x16[2][0], accumulator_tiles_i32x16[2][1], accumulator_tiles_i32x16[2][2],
                accumulator_tiles_i32x16[2][3]);
            __m128i query_3_coarse_dots_i32x4 = nk_maxsim_reduce_i32x16x4_icelake_(
                accumulator_tiles_i32x16[3][0], accumulator_tiles_i32x16[3][1], accumulator_tiles_i32x16[3][2],
                accumulator_tiles_i32x16[3][3]);

            __m128i bias_correction_i32x4 = _mm_set_epi32(
                128 * document_metadata[document_block_start_index + 3].sum_i8_i32,
                128 * document_metadata[document_block_start_index + 2].sum_i8_i32,
                128 * document_metadata[document_block_start_index + 1].sum_i8_i32,
                128 * document_metadata[document_block_start_index + 0].sum_i8_i32);
            query_0_coarse_dots_i32x4 = _mm_sub_epi32(query_0_coarse_dots_i32x4, bias_correction_i32x4);
            query_1_coarse_dots_i32x4 = _mm_sub_epi32(query_1_coarse_dots_i32x4, bias_correction_i32x4);
            query_2_coarse_dots_i32x4 = _mm_sub_epi32(query_2_coarse_dots_i32x4, bias_correction_i32x4);
            query_3_coarse_dots_i32x4 = _mm_sub_epi32(query_3_coarse_dots_i32x4, bias_correction_i32x4);

            // 4x4 transpose: [query][doc] → [doc][query] for vectorized argmax
            __m128i transpose_queries_01_low_i32x4 = _mm_unpacklo_epi32(query_0_coarse_dots_i32x4,
                                                                        query_1_coarse_dots_i32x4);
            __m128i transpose_queries_23_low_i32x4 = _mm_unpacklo_epi32(query_2_coarse_dots_i32x4,
                                                                        query_3_coarse_dots_i32x4);
            __m128i transpose_queries_01_high_i32x4 = _mm_unpackhi_epi32(query_0_coarse_dots_i32x4,
                                                                         query_1_coarse_dots_i32x4);
            __m128i transpose_queries_23_high_i32x4 = _mm_unpackhi_epi32(query_2_coarse_dots_i32x4,
                                                                         query_3_coarse_dots_i32x4);
            __m128i document_0_dots_i32x4 = _mm_unpacklo_epi64(transpose_queries_01_low_i32x4,
                                                               transpose_queries_23_low_i32x4);
            __m128i document_1_dots_i32x4 = _mm_unpackhi_epi64(transpose_queries_01_low_i32x4,
                                                               transpose_queries_23_low_i32x4);
            __m128i document_2_dots_i32x4 = _mm_unpacklo_epi64(transpose_queries_01_high_i32x4,
                                                               transpose_queries_23_high_i32x4);
            __m128i document_3_dots_i32x4 = _mm_unpackhi_epi64(transpose_queries_01_high_i32x4,
                                                               transpose_queries_23_high_i32x4);

            __m128i comparison_mask_i32x4, document_index_i32x4;

            comparison_mask_i32x4 = _mm_cmpgt_epi32(document_0_dots_i32x4, running_max_i32x4);
            document_index_i32x4 = _mm_set1_epi32((int)(document_block_start_index + 0));
            running_max_i32x4 = _mm_blendv_epi8(running_max_i32x4, document_0_dots_i32x4, comparison_mask_i32x4);
            running_argmax_i32x4 = _mm_blendv_epi8(running_argmax_i32x4, document_index_i32x4, comparison_mask_i32x4);

            comparison_mask_i32x4 = _mm_cmpgt_epi32(document_1_dots_i32x4, running_max_i32x4);
            document_index_i32x4 = _mm_set1_epi32((int)(document_block_start_index + 1));
            running_max_i32x4 = _mm_blendv_epi8(running_max_i32x4, document_1_dots_i32x4, comparison_mask_i32x4);
            running_argmax_i32x4 = _mm_blendv_epi8(running_argmax_i32x4, document_index_i32x4, comparison_mask_i32x4);

            comparison_mask_i32x4 = _mm_cmpgt_epi32(document_2_dots_i32x4, running_max_i32x4);
            document_index_i32x4 = _mm_set1_epi32((int)(document_block_start_index + 2));
            running_max_i32x4 = _mm_blendv_epi8(running_max_i32x4, document_2_dots_i32x4, comparison_mask_i32x4);
            running_argmax_i32x4 = _mm_blendv_epi8(running_argmax_i32x4, document_index_i32x4, comparison_mask_i32x4);

            comparison_mask_i32x4 = _mm_cmpgt_epi32(document_3_dots_i32x4, running_max_i32x4);
            document_index_i32x4 = _mm_set1_epi32((int)(document_block_start_index + 3));
            running_max_i32x4 = _mm_blendv_epi8(running_max_i32x4, document_3_dots_i32x4, comparison_mask_i32x4);
            running_argmax_i32x4 = _mm_blendv_epi8(running_argmax_i32x4, document_index_i32x4, comparison_mask_i32x4);
        }

        // Document tail: 4Q×1D
        for (nk_size_t document_index = document_block_start_index; document_index < document_count; document_index++) {
            nk_i8_t const *document_i8_row = document_i8 + document_index * depth_i8_padded;

            __m512i accumulator_i32x16_0 = _mm512_setzero_si512();
            __m512i accumulator_i32x16_1 = _mm512_setzero_si512();
            __m512i accumulator_i32x16_2 = _mm512_setzero_si512();
            __m512i accumulator_i32x16_3 = _mm512_setzero_si512();

            for (nk_size_t depth_index = 0; depth_index < depth_i8_padded; depth_index += 64) {
                __m512i document_i8x64 = _mm512_loadu_si512((__m512i const *)(document_i8_row + depth_index));

                accumulator_i32x16_0 = _mm512_dpbusd_epi32(
                    accumulator_i32x16_0,
                    _mm512_xor_si512(
                        _mm512_loadu_si512((
                            __m512i const *)(query_i8 + (query_block_start_index + 0) * depth_i8_padded + depth_index)),
                        xor_mask_u8x64),
                    document_i8x64);
                accumulator_i32x16_1 = _mm512_dpbusd_epi32(
                    accumulator_i32x16_1,
                    _mm512_xor_si512(
                        _mm512_loadu_si512((
                            __m512i const *)(query_i8 + (query_block_start_index + 1) * depth_i8_padded + depth_index)),
                        xor_mask_u8x64),
                    document_i8x64);
                accumulator_i32x16_2 = _mm512_dpbusd_epi32(
                    accumulator_i32x16_2,
                    _mm512_xor_si512(
                        _mm512_loadu_si512((
                            __m512i const *)(query_i8 + (query_block_start_index + 2) * depth_i8_padded + depth_index)),
                        xor_mask_u8x64),
                    document_i8x64);
                accumulator_i32x16_3 = _mm512_dpbusd_epi32(
                    accumulator_i32x16_3,
                    _mm512_xor_si512(
                        _mm512_loadu_si512((
                            __m512i const *)(query_i8 + (query_block_start_index + 3) * depth_i8_padded + depth_index)),
                        xor_mask_u8x64),
                    document_i8x64);
            }

            nk_i32_t bias_correction_i32 = 128 * document_metadata[document_index].sum_i8_i32;
            __m128i coarse_dots_i32x4 = _mm_set_epi32(
                _mm512_reduce_add_epi32(accumulator_i32x16_3) - bias_correction_i32,
                _mm512_reduce_add_epi32(accumulator_i32x16_2) - bias_correction_i32,
                _mm512_reduce_add_epi32(accumulator_i32x16_1) - bias_correction_i32,
                _mm512_reduce_add_epi32(accumulator_i32x16_0) - bias_correction_i32);

            __m128i comparison_mask_i32x4 = _mm_cmpgt_epi32(coarse_dots_i32x4, running_max_i32x4);
            __m128i document_index_i32x4 = _mm_set1_epi32((int)document_index);
            running_max_i32x4 = _mm_blendv_epi8(running_max_i32x4, coarse_dots_i32x4, comparison_mask_i32x4);
            running_argmax_i32x4 = _mm_blendv_epi8(running_argmax_i32x4, document_index_i32x4, comparison_mask_i32x4);
        }

        best_document_indices[query_block_start_index + 0] = (nk_u32_t)_mm_extract_epi32(running_argmax_i32x4, 0);
        best_document_indices[query_block_start_index + 1] = (nk_u32_t)_mm_extract_epi32(running_argmax_i32x4, 1);
        best_document_indices[query_block_start_index + 2] = (nk_u32_t)_mm_extract_epi32(running_argmax_i32x4, 2);
        best_document_indices[query_block_start_index + 3] = (nk_u32_t)_mm_extract_epi32(running_argmax_i32x4, 3);
    }

    // Query tail: 1Q×1D
    for (nk_size_t query_index = query_block_start_index; query_index < query_count; query_index++) {
        nk_i8_t const *query_i8_row = query_i8 + query_index * depth_i8_padded;
        nk_i32_t running_max_i32 = NK_I32_MIN;
        nk_u32_t running_argmax_u32 = 0;

        for (nk_size_t document_index = 0; document_index < document_count; document_index++) {
            nk_i8_t const *document_i8_row = document_i8 + document_index * depth_i8_padded;
            __m512i accumulator_i32x16 = _mm512_setzero_si512();

            for (nk_size_t depth_index = 0; depth_index < depth_i8_padded; depth_index += 64) {
                __m512i document_i8x64 = _mm512_loadu_si512((__m512i const *)(document_i8_row + depth_index));
                __m512i query_biased_u8x64 = _mm512_xor_si512(
                    _mm512_loadu_si512((__m512i const *)(query_i8_row + depth_index)), xor_mask_u8x64);
                accumulator_i32x16 = _mm512_dpbusd_epi32(accumulator_i32x16, query_biased_u8x64, document_i8x64);
            }

            nk_i32_t coarse_dot_i32 = _mm512_reduce_add_epi32(accumulator_i32x16) -
                                      128 * document_metadata[document_index].sum_i8_i32;

            if (coarse_dot_i32 > running_max_i32) {
                running_max_i32 = coarse_dot_i32;
                running_argmax_u32 = (nk_u32_t)document_index;
            }
        }

        best_document_indices[query_index] = running_argmax_u32;
    }
}

#pragma endregion

#pragma region Compute Functions

NK_PUBLIC void nk_maxsim_packed_f32_icelake( //
    void const *query_packed, void const *document_packed, nk_size_t query_count, nk_size_t document_count,
    nk_size_t depth, nk_f64_t *result) {

    nk_maxsim_packed_regions_t regions = nk_maxsim_extract_packed_regions_(query_packed, document_packed);
    nk_f64_t total_angular_distance = 0.0;

    for (nk_size_t chunk_start = 0; chunk_start < query_count; chunk_start += 256) {
        nk_size_t chunk_size = query_count - chunk_start < 256 ? query_count - chunk_start : 256;
        nk_u32_t best_document_indices[256];

        nk_maxsim_coarse_argmax_icelake_(regions.query_quantized + chunk_start * regions.depth_i8_padded,
                                         regions.document_quantized, regions.document_metadata, chunk_size,
                                         document_count, regions.depth_i8_padded, best_document_indices);

        for (nk_size_t query_index = 0; query_index < chunk_size; query_index++) {
            nk_u32_t best_document_index = best_document_indices[query_index];
            nk_f64_t dot_result;
            nk_dot_f32(
                (nk_f32_t const *)(regions.query_originals +
                                   (chunk_start + query_index) * regions.query_original_stride),
                (nk_f32_t const *)(regions.document_originals + best_document_index * regions.document_original_stride),
                depth, &dot_result);
            nk_f64_t cosine = dot_result *
                              (nk_f64_t)regions.query_metadata[chunk_start + query_index].inverse_norm_f32 *
                              (nk_f64_t)regions.document_metadata[best_document_index].inverse_norm_f32;
            nk_f64_t angular = 1.0 - cosine;
            if (angular < 0.0) angular = 0.0;
            total_angular_distance += angular;
        }
    }

    *result = total_angular_distance;
}

NK_PUBLIC void nk_maxsim_packed_f16_icelake( //
    void const *query_packed, void const *document_packed, nk_size_t query_count, nk_size_t document_count,
    nk_size_t depth, nk_f32_t *result) {

    nk_maxsim_packed_regions_t regions = nk_maxsim_extract_packed_regions_(query_packed, document_packed);
    nk_f64_t total_angular_distance = 0.0;

    for (nk_size_t chunk_start = 0; chunk_start < query_count; chunk_start += 256) {
        nk_size_t chunk_size = query_count - chunk_start < 256 ? query_count - chunk_start : 256;
        nk_u32_t best_document_indices[256];

        nk_maxsim_coarse_argmax_icelake_(regions.query_quantized + chunk_start * regions.depth_i8_padded,
                                         regions.document_quantized, regions.document_metadata, chunk_size,
                                         document_count, regions.depth_i8_padded, best_document_indices);

        for (nk_size_t query_index = 0; query_index < chunk_size; query_index++) {
            nk_u32_t best_document_index = best_document_indices[query_index];
            nk_f32_t dot_result;
            nk_dot_f16(
                (nk_f16_t const *)(regions.query_originals +
                                   (chunk_start + query_index) * regions.query_original_stride),
                (nk_f16_t const *)(regions.document_originals + best_document_index * regions.document_original_stride),
                depth, &dot_result);
            nk_f32_t cosine = dot_result * regions.query_metadata[chunk_start + query_index].inverse_norm_f32 *
                              regions.document_metadata[best_document_index].inverse_norm_f32;
            nk_f32_t angular = 1.0f - cosine;
            if (angular < 0.0f) angular = 0.0f;
            total_angular_distance += (nk_f64_t)angular;
        }
    }

    *result = (nk_f32_t)total_angular_distance;
}

#pragma endregion

#if defined(__clang__)
#pragma clang attribute pop
#elif defined(__GNUC__)
#pragma GCC pop_options
#endif

#if defined(__cplusplus)
} // extern "C"
#endif

#endif // NK_TARGET_ICELAKE
#endif // NK_TARGET_X86_
#endif // NK_MAXSIM_ICELAKE_H
