64 lines
2.7 KiB
C
64 lines
2.7 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 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/intrin/pcmpeqb.h"
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#include "libc/intrin/pmovmskb.h"
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#include "libc/limits.h"
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#include "libc/nexgen32e/bsf.h"
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#include "libc/str/str.h"
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/**
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* Copies bytes from 𝑠 to 𝑑 until a NUL is encountered.
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*
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* @param 𝑑 is destination memory
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* @param 𝑠 is a NUL-terminated string
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* @note 𝑑 and 𝑠 can't overlap
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* @return original dest
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* @see memccpy()
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* @asyncsignalsafe
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*/
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char *strcpy(char *d, const char *s) {
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size_t i;
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uint8_t v1[16], v2[16], vz[16];
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i = 0;
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while (((uintptr_t)(s + i) & 15)) {
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if (!(d[i] = s[i])) {
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return d;
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}
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++i;
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}
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for (;;) {
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memset(vz, 0, 16);
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memcpy(v1, s + i, 16);
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pcmpeqb(v2, v1, vz);
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if (!pmovmskb(v2)) {
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memcpy(d + i, v1, 16);
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i += 16;
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} else {
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break;
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}
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}
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for (;;) {
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if (!(d[i] = s[i])) {
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return d;
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}
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++i;
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}
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}
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