cosmopolitan/libc/intrin/stpcpy.c
Justine Tunney cc1732bc42
Make AARCH64 harder, better, faster, stronger
- Perform some housekeeping on scalar math function code
- Import ARM's Optimized Routines for SIMD string processing
- Upgrade to latest Chromium zlib and enable more SIMD optimizations
2023-05-15 02:15:34 -07:00

70 lines
2.9 KiB
C
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/str/str.h"
#ifndef __aarch64__
// TODO(jart): ASAN support here is important.
typedef char xmm_u __attribute__((__vector_size__(16), __aligned__(1)));
typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
#ifdef __x86_64__
static inline noasan size_t stpcpy_sse2(char *d, const char *s, size_t i) {
xmm_t v, z = {0};
for (;;) {
v = *(xmm_t *)(s + i);
if (!__builtin_ia32_pmovmskb128(v == z)) {
*(xmm_u *)(d + i) = v;
i += 16;
} else {
break;
}
}
return i;
}
#endif
/**
* Copies bytes from 𝑠 to 𝑑 until a NUL is encountered.
*
* @param 𝑑 is destination memory
* @param 𝑠 is a NUL-terminated string
* @note 𝑑 and 𝑠 can't overlap
* @return pointer to nul byte
* @asyncsignalsafe
*/
char *stpcpy(char *d, const char *s) {
size_t i = 0;
#ifdef __x86_64__
for (; (uintptr_t)(s + i) & 15; ++i) {
if (!(d[i] = s[i])) {
return d + i;
}
}
i = stpcpy_sse2(d, s, i);
#endif
for (;;) {
if (!(d[i] = s[i])) {
return d + i;
}
++i;
}
}
#endif /* __aarch64__ */