opencv

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/*
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 * SSE optimized hash slide
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 *
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 * Copyright (C) 2017 Intel Corporation
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 * Authors:
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 *   Arjan van de Ven   <arjan@linux.intel.com>
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 *   Jim Kukunas        <james.t.kukunas@linux.intel.com>
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 *
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 * For conditions of distribution and use, see copyright notice in zlib.h
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 */
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#include "../../zbuild.h"
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#include "../../deflate.h"
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#include <immintrin.h>
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#include <assert.h>
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static inline void slide_hash_chain(Pos *table0, Pos *table1, uint32_t entries0,
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                                    uint32_t entries1, const __m128i wsize) {
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    uint32_t entries;
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    Pos *table;
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    __m128i value0, value1, result0, result1;
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    int on_chain = 0;
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next_chain:
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    table = (on_chain) ? table1 : table0;
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    entries = (on_chain) ? entries1 : entries0;
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    table += entries;
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    table -= 16;
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    /* ZALLOC allocates this pointer unless the user chose a custom allocator.
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     * Our alloc function is aligned to 64 byte boundaries */
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    do {
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        value0 = _mm_load_si128((__m128i *)table);
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        value1 = _mm_load_si128((__m128i *)(table + 8));
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        result0 = _mm_subs_epu16(value0, wsize);
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        result1 = _mm_subs_epu16(value1, wsize);
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        _mm_store_si128((__m128i *)table, result0);
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        _mm_store_si128((__m128i *)(table + 8), result1);
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        table -= 16;
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        entries -= 16;
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    } while (entries > 0);
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    ++on_chain;
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    if (on_chain > 1) {
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        return;
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    } else {
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        goto next_chain;
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    }
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}
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Z_INTERNAL void slide_hash_sse2(deflate_state *s) {
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    uint16_t wsize = (uint16_t)s->w_size;
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    const __m128i xmm_wsize = _mm_set1_epi16((short)wsize);
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    assert(((uintptr_t)s->head & 15) == 0);
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    assert(((uintptr_t)s->prev & 15) == 0);
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    slide_hash_chain(s->head, s->prev, HASH_SIZE, wsize, xmm_wsize);
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}
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