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/* compare256_power9.c - Power9 version of compare256
* Copyright (C) 2019 Matheus Castanho <msc@linux.ibm.com>, IBM
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#ifdef POWER9
#include <altivec.h>
#include "zbuild.h"
#include "zmemory.h"
#include "deflate.h"
#include "zendian.h"
/* Older versions of GCC misimplemented semantics for these bit counting builtins.
* https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=3f30f2d1dbb3228b8468b26239fe60c2974ce2ac */
#if defined(__GNUC__) && !defined(__clang__) && (__GNUC__ < 12)
#if BYTE_ORDER == LITTLE_ENDIAN
# define zng_vec_vctzlsbb(vc, len) len = __builtin_vec_vctzlsbb(vc)
#else
# define zng_vec_vctzlsbb(vc, len) len = __builtin_vec_vclzlsbb(vc)
#endif
#else
# define zng_vec_vctzlsbb(vc, len) len = vec_cntlz_lsbb(vc)
#endif
static inline uint32_t compare256_power9_static(const uint8_t *src0, const uint8_t *src1) {
uint32_t len = 0, cmplen;
do {
vector unsigned char vsrc0, vsrc1, vc;
vsrc0 = *((vector unsigned char *)src0);
vsrc1 = *((vector unsigned char *)src1);
/* Compare 16 bytes at a time. Each byte of vc will be either
* all ones or all zeroes, depending on the result of the comparison. */
vc = (vector unsigned char)vec_cmpne(vsrc0, vsrc1);
/* Since the index of matching bytes will contain only zeroes
* on vc (since we used cmpne), counting the number of consecutive
* bytes where LSB == 0 is the same as counting the length of the match. */
zng_vec_vctzlsbb(vc, cmplen);
if (cmplen != 16)
return len + cmplen;
src0 += 16, src1 += 16, len += 16;
} while (len < 256);
return 256;
}
Z_INTERNAL uint32_t compare256_power9(const uint8_t *src0, const uint8_t *src1) {
return compare256_power9_static(src0, src1);
}
#define LONGEST_MATCH longest_match_power9
#define COMPARE256 compare256_power9_static
#include "match_tpl.h"
#define LONGEST_MATCH_SLOW
#define LONGEST_MATCH longest_match_slow_power9
#define COMPARE256 compare256_power9_static
#include "match_tpl.h"
#endif
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