mirror of
https://github.com/jart/cosmopolitan.git
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2ab9e9f7fd
- Introduce portable sched_getcpu() api - Support GCC's __target_clones__ feature - Make fma() go faster on x86 in default mode - Remove some asan checks from core libraries - WinMain() now ensures $HOME and $USER are defined
81 lines
3.3 KiB
C
81 lines
3.3 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/limits.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/str/str.h"
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#ifndef __aarch64__
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typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(1)));
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static inline const unsigned char *memrchr_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 = 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 inline const unsigned char *memrchr_sse(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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unsigned m;
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xmm_t v, t = {c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c};
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for (i = n; i >= 16;) {
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v = *(const xmm_t *)(s + (i -= 16));
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m = __builtin_ia32_pmovmskb128(v == t);
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if (m) {
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m = __builtin_clzl(m) ^ (sizeof(long) * CHAR_BIT - 1);
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return s + i + m;
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}
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}
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while (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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#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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__vex void *memrchr(const void *s, int c, size_t n) {
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#if defined(__x86_64__) && !defined(__chibicc__)
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const void *r;
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r = memrchr_sse(s, c, n);
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return (void *)r;
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#else
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return (void *)memrchr_pure(s, c, n);
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#endif
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}
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#endif /* __aarch64__ */
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