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/* Optimized slide_hash for PowerPC processors
* Copyright (C) 2017-2021 Mika T. Lindqvist <postmaster@raasu.org>
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include <altivec.h>
#include "zbuild.h"
#include "deflate.h"
static inline void slide_hash_chain(Pos *table, uint32_t entries, uint16_t wsize) {
const vector unsigned short vmx_wsize = vec_splats(wsize);
Pos *p = table;
do {
/* Do the pointer arithmetic early to hopefully overlap the vector unit */
Pos *q = p;
p += 32;
vector unsigned short value0, value1, value2, value3;
vector unsigned short result0, result1, result2, result3;
value0 = vec_ld(0, q);
value1 = vec_ld(16, q);
value2 = vec_ld(32, q);
value3 = vec_ld(48, q);
result0 = vec_subs(value0, vmx_wsize);
result1 = vec_subs(value1, vmx_wsize);
result2 = vec_subs(value2, vmx_wsize);
result3 = vec_subs(value3, vmx_wsize);
vec_st(result0, 0, q);
vec_st(result1, 16, q);
vec_st(result2, 32, q);
vec_st(result3, 48, q);
entries -= 32;
} while (entries);
}
void Z_INTERNAL SLIDE_PPC(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);
}
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