opencv

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/* adler32_sse42.c -- compute the Adler-32 checksum of a data stream
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 * Copyright (C) 1995-2011 Mark Adler
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 * Authors:
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 *   Adam Stylinski <kungfujesus06@gmail.com>
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 *   Brian Bockelman <bockelman@gmail.com>
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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 "../../adler32_p.h"
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#include "../../adler32_fold.h"
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#include "adler32_ssse3_p.h"
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#include <immintrin.h>
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#ifdef X86_SSE42
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Z_INTERNAL uint32_t adler32_fold_copy_sse42(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len) {
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    uint32_t adler0, adler1;
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    adler1 = (adler >> 16) & 0xffff;
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    adler0 = adler & 0xffff;
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rem_peel:
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    if (len < 16) {
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       return adler32_copy_len_16(adler0, src, dst, len, adler1);
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    }
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    __m128i vbuf, vbuf_0;
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    __m128i vs1_0, vs3, vs1, vs2, vs2_0, v_sad_sum1, v_short_sum2, v_short_sum2_0,
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            v_sad_sum2, vsum2, vsum2_0;
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    __m128i zero = _mm_setzero_si128();
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    const __m128i dot2v = _mm_setr_epi8(32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17);
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    const __m128i dot2v_0 = _mm_setr_epi8(16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1);
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    const __m128i dot3v = _mm_set1_epi16(1);
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    size_t k;
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    while (len >= 16) {
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        k = MIN(len, NMAX);
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        k -= k % 16;
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        len -= k;
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        vs1 = _mm_cvtsi32_si128(adler0);
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        vs2 = _mm_cvtsi32_si128(adler1);
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        vs3 = _mm_setzero_si128();
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        vs2_0 = _mm_setzero_si128();
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        vs1_0 = vs1;
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        while (k >= 32) {
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            /*
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               vs1 = adler + sum(c[i])
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               vs2 = sum2 + 16 vs1 + sum( (16-i+1) c[i] )
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            */
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            vbuf = _mm_loadu_si128((__m128i*)src);
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            vbuf_0 = _mm_loadu_si128((__m128i*)(src + 16));
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            src += 32;
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            k -= 32;
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            v_sad_sum1 = _mm_sad_epu8(vbuf, zero);
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            v_sad_sum2 = _mm_sad_epu8(vbuf_0, zero);
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            _mm_storeu_si128((__m128i*)dst, vbuf);
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            _mm_storeu_si128((__m128i*)(dst + 16), vbuf_0);
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            dst += 32;
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            v_short_sum2 = _mm_maddubs_epi16(vbuf, dot2v);
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            v_short_sum2_0 = _mm_maddubs_epi16(vbuf_0, dot2v_0);
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            vs1 = _mm_add_epi32(v_sad_sum1, vs1);
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            vs3 = _mm_add_epi32(vs1_0, vs3);
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            vsum2 = _mm_madd_epi16(v_short_sum2, dot3v);
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            vsum2_0 = _mm_madd_epi16(v_short_sum2_0, dot3v);
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            vs1 = _mm_add_epi32(v_sad_sum2, vs1);
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            vs2 = _mm_add_epi32(vsum2, vs2);
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            vs2_0 = _mm_add_epi32(vsum2_0, vs2_0);
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            vs1_0 = vs1;
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        }
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        vs2 = _mm_add_epi32(vs2_0, vs2);
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        vs3 = _mm_slli_epi32(vs3, 5);
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        vs2 = _mm_add_epi32(vs3, vs2);
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        vs3 = _mm_setzero_si128();
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        while (k >= 16) {
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            /*
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               vs1 = adler + sum(c[i])
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               vs2 = sum2 + 16 vs1 + sum( (16-i+1) c[i] )
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            */
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            vbuf = _mm_loadu_si128((__m128i*)src);
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            src += 16;
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            k -= 16;
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            v_sad_sum1 = _mm_sad_epu8(vbuf, zero);
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            v_short_sum2 = _mm_maddubs_epi16(vbuf, dot2v_0);
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            vs1 = _mm_add_epi32(v_sad_sum1, vs1);
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            vs3 = _mm_add_epi32(vs1_0, vs3);
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            vsum2 = _mm_madd_epi16(v_short_sum2, dot3v);
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            vs2 = _mm_add_epi32(vsum2, vs2);
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            vs1_0 = vs1;
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            _mm_storeu_si128((__m128i*)dst, vbuf);
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            dst += 16;
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        }
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        vs3 = _mm_slli_epi32(vs3, 4);
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        vs2 = _mm_add_epi32(vs2, vs3);
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        adler0 = partial_hsum(vs1) % BASE;
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        adler1 = hsum(vs2) % BASE;
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    }
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    /* If this is true, there's fewer than 16 elements remaining */
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    if (len) {
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        goto rem_peel;
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    }
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    return adler0 | (adler1 << 16);
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}
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#endif
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