arch/generic/chunk_permute_table.h

/* chunk_permute_table.h - shared AVX/SSE4 permutation table for use with chunkmemset family of functions.
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

#ifndef CHUNK_PERMUTE_TABLE_H_
#define CHUNK_PERMUTE_TABLE_H_

#include "zbuild.h"

/* Need entries for all numbers not an even modulus for 1, 2, 4, 8, 16 & 32 */
static const ALIGNED_(32) uint8_t permute_table[26*32] = {
    0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, /* dist 3 */
    0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, /* dist 5 */
    0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, /* dist 6 */
    0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, /* dist 7 */
    0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 1, 2, 3, 4, /* dist 9 */
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, /* dist 10 */
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, /* dist 11 */
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 0, 1, 2, 3, 4, 5, 6, 7, /* dist 12 */
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 0, 1, 2, 3, 4, 5, /* dist 13 */
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 0, 1, 2, 3, /* dist 14 */
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0, 1, /* dist 15 */

    /* Beyond dists of 15 means we have to permute from a vector > len(m128i). Because AVX couldn't permute
     * beyond 128 bit lanes until AVX512 for sub 4-byte sequences, we have to do some math here for an eventual
     * blend with a comparison. That means we need to wrap the indices with yet another derived table. For simplicity,
     * we'll use absolute indexing here to derive a blend vector. This is actually a lot simpler with ARM's TBL, but,
     * this is what we're dealt.
     */

    16, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* dist 17 */
    16, 17, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, /* dist 18 */
    16, 17, 18, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, /* dist 19 */
    16, 17, 18, 19, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, /* dist 20 */
    16, 17, 18, 19, 20, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, /* dist 21 */
    16, 17, 18, 19, 20, 21, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, /* dist 22 */
    16, 17, 18, 19, 20, 21, 22, 0, 1, 2, 3, 4, 5, 6, 7, 8, /* dist 23 */
    16, 17, 18, 19, 20, 21, 22, 23, 0, 1, 2, 3, 4, 5, 6, 7, /* dist 24 */
    16, 17, 18, 19, 20, 21, 22, 23, 24, 0, 1, 2, 3, 4, 5, 6, /* dist 25 */
    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 1, 2, 3, 4, 5, /* dist 26 */
    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 0, 1, 2, 3, 4, /* dist 27 */
    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 0, 1, 2, 3, /* dist 28 */
    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 0, 1, 2, /* dist 29 */
    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 0, 1, /* dist 30 */
    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 0, /* dist 31 */
};

typedef struct lut_rem_pair_s {
    uint16_t idx;
    uint16_t remval;
} lut_rem_pair;

#endif