Aaru.Checksums.Native/fletcher32_ssse3.c

/*
 * This file is part of the Aaru Data Preservation Suite.
 * Copyright (c) 2019-2025 Natalia Portillo.
 * Copyright 2017 The Chromium Authors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *    * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *    * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#if defined(__x86_64__) || defined(__amd64) || defined(_M_AMD64) || defined(_M_X64) || defined(__I386__) || \
    defined(__i386__) || defined(__THW_INTEL) || defined(_M_IX86)

#include <stdint.h>
#include <tmmintrin.h>

#include "library.h"
#include "fletcher32.h"

/**
 * @brief Calculate Fletcher-32 checksum for a given data using SSSE3 instructions.
 *
 * This function calculates the Fletcher-32 checksum for a block of data using SSSE3 vector instructions.
 *
 * @param sum1 Pointer to the variable where the first 16-bit checksum value is stored.
 * @param sum2 Pointer to the variable where the second 16-bit checksum value is stored.
 * @param data Pointer to the data buffer.
 * @param len Length of the data buffer in bytes.
 */
AARU_EXPORT TARGET_WITH_SSSE3 void AARU_CALL fletcher32_ssse3(uint16_t *sum1, uint16_t *sum2, const uint8_t *data,
                                                              long len)
{
    uint32_t s1 = *sum1;
    uint32_t s2 = *sum2;

    /*
     * Process the data in blocks.
     */
    const unsigned BLOCK_SIZE = 1 << 5;
    if(len >= BLOCK_SIZE)
    {
        long blocks = len / BLOCK_SIZE;
        len -= blocks * BLOCK_SIZE;
        while(blocks)
        {
            unsigned n = NMAX / BLOCK_SIZE; /* The NMAX constraint. */
            if(n > blocks) n = (unsigned)blocks;
            blocks -= n;
            const __m128i tap1 = _mm_setr_epi8(32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17);
            const __m128i tap2 = _mm_setr_epi8(16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1);
            const __m128i zero = _mm_setr_epi8(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
            const __m128i ones = _mm_set_epi16(1, 1, 1, 1, 1, 1, 1, 1);
            /*
             * Process n blocks of data. At most NMAX data bytes can be
             * processed before s2 must be reduced modulo BASE.
             */
            __m128i       v_ps = _mm_set_epi32(0, 0, 0, s1 * n);
            __m128i       v_s2 = _mm_set_epi32(0, 0, 0, s2);
            __m128i       v_s1 = _mm_set_epi32(0, 0, 0, 0);
            do {
                /*
                 * Load 32 input bytes.
                 */
                const __m128i bytes1 = _mm_loadu_si128((__m128i *)(data));
                const __m128i bytes2 = _mm_loadu_si128((__m128i *)(data + 16));
                /*
                 * Add previous block byte sum to v_ps.
                 */
                v_ps                 = _mm_add_epi32(v_ps, v_s1);
                /*
                 * Horizontally add the bytes for s1, multiply-adds the
                 * bytes by [ 32, 31, 30, ... ] for s2.
                 */
                v_s1                 = _mm_add_epi32(v_s1, _mm_sad_epu8(bytes1, zero));
                const __m128i mad1   = _mm_maddubs_epi16(bytes1, tap1);
                v_s2                 = _mm_add_epi32(v_s2, _mm_madd_epi16(mad1, ones));
                v_s1                 = _mm_add_epi32(v_s1, _mm_sad_epu8(bytes2, zero));
                const __m128i mad2   = _mm_maddubs_epi16(bytes2, tap2);
                v_s2                 = _mm_add_epi32(v_s2, _mm_madd_epi16(mad2, ones));
                data += BLOCK_SIZE;
            } while(--n);
            v_s2 = _mm_add_epi32(v_s2, _mm_slli_epi32(v_ps, 5));
            /*
             * Sum epi32 ints v_s1(s2) and accumulate in s1(s2).
             */
#define S23O1 _MM_SHUFFLE(2, 3, 0, 1) /* A B C D -> B A D C */
#define S1O32 _MM_SHUFFLE(1, 0, 3, 2) /* A B C D -> C D A B */
            v_s1 = _mm_add_epi32(v_s1, _mm_shuffle_epi32(v_s1, S23O1));
            v_s1 = _mm_add_epi32(v_s1, _mm_shuffle_epi32(v_s1, S1O32));
            s1 += _mm_cvtsi128_si32(v_s1);
            v_s2 = _mm_add_epi32(v_s2, _mm_shuffle_epi32(v_s2, S23O1));
            v_s2 = _mm_add_epi32(v_s2, _mm_shuffle_epi32(v_s2, S1O32));
            s2   = _mm_cvtsi128_si32(v_s2);
#undef S23O1
#undef S1O32
            /*
             * Reduce.
             */
            s1 %= FLETCHER32_MODULE;
            s2 %= FLETCHER32_MODULE;
        }
    }

    /*
     * Handle leftover data.
     */
    if(len)
    {
        if(len >= 16)
        {
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            s2 += (s1 += *data++);
            len -= 16;
        }
        while(len--) { s2 += (s1 += *data++); }
        if(s1 >= FLETCHER32_MODULE) s1 -= FLETCHER32_MODULE;
        s2 %= FLETCHER32_MODULE;
    }

    /*
     * Return the recombined sums.
     */
    *sum1 = s1 & 0xFFFF;
    *sum2 = s2 & 0xFFFF;
}

#endif