mirror of
https://github.com/jart/cosmopolitan.git
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82 lines
3.4 KiB
C
82 lines
3.4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dce.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/str/str.h"
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#include "third_party/aarch64/arm_neon.internal.h"
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#include "third_party/intel/immintrin.internal.h"
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#ifndef __aarch64__
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static inline const unsigned char *memchr_pure(const unsigned char *s,
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unsigned char c, size_t n) {
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size_t i;
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for (i = 0; i < n; ++i) {
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if (s[i] == c) {
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return s + i;
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}
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}
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return 0;
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}
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#if defined(__x86_64__) && !defined(__chibicc__)
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static const char *memchr_sse(const char *s, char c, size_t n) {
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const char *e = s + n;
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__m128i t = _mm_set1_epi8(c);
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unsigned m, k = (uintptr_t)s & 15;
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m = _mm_movemask_epi8(
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_mm_cmpeq_epi8(_mm_load_si128((const __m128i *)((uintptr_t)s & -16)), t));
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m >>= k;
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if (m) {
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s += __builtin_ctz(m);
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if (s < e)
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return s;
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return 0;
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}
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for (s += 16 - k; s < e; s += 16) {
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m = _mm_movemask_epi8(
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_mm_cmpeq_epi8(_mm_load_si128((const __m128i *)s), t));
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if (m) {
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s += __builtin_ctz(m);
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if (s < e)
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return s;
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return 0;
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}
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}
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return 0;
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}
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#endif
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/**
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* Returns pointer to first instance of character.
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*
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* @param s is memory to search
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* @param c is search byte which is masked with 255
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* @param n is byte length of p
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* @return is pointer to first instance of c or NULL if not found
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* @asyncsignalsafe
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*/
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void *memchr(const void *s, int c, size_t n) {
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#if defined(__x86_64__) && !defined(__chibicc__)
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return (void *)memchr_sse(s, c, n);
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#else
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return (void *)memchr_pure(s, c, n);
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#endif
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}
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#endif /* __aarch64__ */
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