mirror of
https://github.com/jart/cosmopolitan.git
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99 lines
3.9 KiB
C
99 lines
3.9 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net 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/assert.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/str/str.h"
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static inline const unsigned char *rawmemchr_pure(const unsigned char *s,
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unsigned char c) {
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for (;; ++s) {
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if (*s == c) {
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return s;
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}
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}
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}
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#if defined(__x86_64__) && !defined(__chibicc__)
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typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
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dontasan static inline const char *rawmemchr_sse(const char *s,
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unsigned char c) {
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unsigned k;
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unsigned m;
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xmm_t v, *p;
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xmm_t n = {c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c};
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k = (uintptr_t)s & 15;
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p = (const xmm_t *)((uintptr_t)s & -16);
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v = *p;
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m = __builtin_ia32_pmovmskb128(v == n);
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m >>= k;
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m <<= k;
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while (!m) {
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v = *++p;
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m = __builtin_ia32_pmovmskb128(v == n);
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}
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m = __builtin_ctzll(m);
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return (const char *)p + m;
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}
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#endif
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static inline dontasan uint64_t UncheckedAlignedRead64(unsigned char *p) {
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return (uint64_t)p[7] << 070 | (uint64_t)p[6] << 060 | (uint64_t)p[5] << 050 |
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(uint64_t)p[4] << 040 | (uint64_t)p[3] << 030 | (uint64_t)p[2] << 020 |
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(uint64_t)p[1] << 010 | (uint64_t)p[0] << 000;
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}
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/**
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* Returns pointer to first instance of character.
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*
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* @param m is memory to search
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* @param c is search byte which is masked with 255
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* @return is pointer to first instance of c
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*/
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void *rawmemchr(const void *s, int c) {
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#if defined(__x86_64__) && !defined(__chibicc__)
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const void *r;
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if (X86_HAVE(SSE)) {
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if (IsAsan()) __asan_verify(s, 1);
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r = rawmemchr_sse(s, c);
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} else {
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r = rawmemchr_pure(s, c);
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}
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return (void *)r;
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#else
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uint64_t v, w;
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const unsigned char *p;
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p = s;
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c &= 255;
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v = 0x0101010101010101ul * c;
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for (; (uintptr_t)p & 7; ++p) {
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if (*p == c) return p;
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}
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for (;; p += 8) {
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w = UncheckedAlignedRead64(p);
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if ((w = ~(w ^ v) & ((w ^ v) - 0x0101010101010101) & 0x8080808080808080)) {
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p += (unsigned)__builtin_ctzll(w) >> 3;
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break;
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}
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}
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assert(*p == c);
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return p;
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#endif
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}
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