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/* slide_hash_neon.c -- Optimized hash table shifting for ARM with support for NEON instructions
* Copyright (C) 2017-2020 Mika T. Lindqvist
*
* Authors:
* Mika T. Lindqvist <postmaster@raasu.org>
* Jun He <jun.he@arm.com>
*
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#ifdef ARM_NEON
#include "neon_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 uint16x8_t v;
uint16x8x4_t p0, p1;
Z_REGISTER size_t n;
size_t size = entries*sizeof(table[0]);
Assert((size % sizeof(uint16x8_t) * 8 == 0), "hash table size err");
Assert(sizeof(Pos) == 2, "Wrong Pos size");
v = vdupq_n_u16(wsize);
n = size / (sizeof(uint16x8_t) * 8);
do {
p0 = vld1q_u16_x4(table);
p1 = vld1q_u16_x4(table+32);
vqsubq_u16_x4_x1(p0, p0, v);
vqsubq_u16_x4_x1(p1, p1, v);
vst1q_u16_x4(table, p0);
vst1q_u16_x4(table+32, p1);
table += 64;
} while (--n);
}
Z_INTERNAL void slide_hash_neon(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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