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/* slide_hash_armv6.c -- Optimized hash table shifting for ARMv6 with support for SIMD instructions
* Copyright (C) 2023 Cameron Cawley
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#if defined(ARM_SIMD)
#include "acle_intrins.h"
#include "zbuild.h"
#include "deflate.h"
/* SIMD version of hash_chain rebase */
static inline void slide_hash_chain(Pos *table, uint32_t entries, uint16_t wsize) {
Z_REGISTER uint16x2_t v;
uint16x2_t p0, p1, p2, p3;
Z_REGISTER size_t n;
size_t size = entries*sizeof(table[0]);
Assert((size % (sizeof(uint16x2_t) * 4) == 0), "hash table size err");
Assert(sizeof(Pos) == 2, "Wrong Pos size");
v = wsize | (wsize << 16);
n = size / (sizeof(uint16x2_t) * 4);
do {
p0 = *((const uint16x2_t *)(table));
p1 = *((const uint16x2_t *)(table+2));
p2 = *((const uint16x2_t *)(table+4));
p3 = *((const uint16x2_t *)(table+6));
p0 = __uqsub16(p0, v);
p1 = __uqsub16(p1, v);
p2 = __uqsub16(p2, v);
p3 = __uqsub16(p3, v);
*((uint16x2_t *)(table)) = p0;
*((uint16x2_t *)(table+2)) = p1;
*((uint16x2_t *)(table+4)) = p2;
*((uint16x2_t *)(table+6)) = p3;
table += 8;
} while (--n);
}
Z_INTERNAL void slide_hash_armv6(deflate_state *s) {
Assert(s->w_size <= UINT16_MAX, "w_size should fit in uint16_t");
uint16_t wsize = (uint16_t)s->w_size;
slide_hash_chain(s->head, HASH_SIZE, wsize);
slide_hash_chain(s->prev, wsize, wsize);
}
#endif
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