mirror of
https://github.com/jart/cosmopolitan.git
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6e6fc38935
Commit bc6c183 introduced a bunch of discrepancies between what files
look like in the repo and what clang-format says they should look like.
However, there were already a few discrepancies prior to that. Most of
these discrepancies seemed to be unintentional, but a few of them were
load-bearing (e.g., a #include that violated header ordering needing
something to have been #defined by a 'later' #include.)
I opted to take what I hope is a relatively smooth-brained approach: I
reverted the .clang-format change, ran clang-format on the whole repo,
reapplied the .clang-format change, reran clang-format again, and then
reverted the commit that contained the first run. Thus the full effect
of this PR should only be to apply the changed formatting rules to the
repo, and from skimming the results, this seems to be the case.
My work can be checked by applying the short, manual commits, and then
rerunning the command listed in the autogenerated commits (those whose
messages I have prefixed auto:) and seeing if your results agree.
It might be that the other diffs should be fixed at some point but I'm
leaving that aside for now.
fd '\.c(c|pp)?$' --print0| xargs -0 clang-format -i
210 lines
8.8 KiB
C
210 lines
8.8 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 2020 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/intrin/likely.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/str/str.h"
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#define PMOVMSKB(x) __builtin_ia32_pmovmskb128(x)
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typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(1)));
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#if defined(__x86_64__) && !defined(__chibicc__)
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static dontinline antiquity int memcmp_sse(const unsigned char *p,
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const unsigned char *q, size_t n) {
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unsigned u;
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if (n > 32) {
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while (n > 16 + 16) {
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if (!(u = PMOVMSKB(*(xmm_t *)p == *(xmm_t *)q) ^ 0xffff)) {
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n -= 16;
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p += 16;
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q += 16;
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} else {
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u = __builtin_ctzl(u);
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return p[u] - q[u];
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}
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}
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}
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if (!(u = PMOVMSKB(*(xmm_t *)p == *(xmm_t *)q) ^ 0xffff)) {
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if (!(u = PMOVMSKB(*(xmm_t *)(p + n - 16) == *(xmm_t *)(q + n - 16)) ^
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0xffff)) {
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return 0;
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} else {
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u = __builtin_ctzl(u);
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return p[n - 16 + u] - q[n - 16 + u];
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}
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} else {
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u = __builtin_ctzl(u);
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return p[u] - q[u];
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}
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}
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_Microarchitecture("avx") static int memcmp_avx(const unsigned char *p,
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const unsigned char *q,
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size_t n) {
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uint64_t w;
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unsigned u;
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if (n > 32) {
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while (n >= 16 + 64) {
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w = (uint64_t)PMOVMSKB(((xmm_t *)p)[0] == ((xmm_t *)q)[0]) << 000 |
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(uint64_t)PMOVMSKB(((xmm_t *)p)[1] == ((xmm_t *)q)[1]) << 020 |
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(uint64_t)PMOVMSKB(((xmm_t *)p)[2] == ((xmm_t *)q)[2]) << 040 |
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(uint64_t)PMOVMSKB(((xmm_t *)p)[3] == ((xmm_t *)q)[3]) << 060;
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if (w == -1) {
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n -= 64;
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p += 64;
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q += 64;
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} else {
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w = __builtin_ctzll(w ^ -1);
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return p[w] - q[w];
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}
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}
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while (n > 16 + 16) {
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if (!(u = PMOVMSKB(*(xmm_t *)p == *(xmm_t *)q) ^ 0xffff)) {
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n -= 16;
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p += 16;
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q += 16;
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} else {
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u = __builtin_ctzl(u);
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return p[u] - q[u];
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}
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}
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}
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if (!(u = PMOVMSKB(*(xmm_t *)p == *(xmm_t *)q) ^ 0xffff)) {
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if (!(u = PMOVMSKB(*(xmm_t *)(p + n - 16) == *(xmm_t *)(q + n - 16)) ^
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0xffff)) {
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return 0;
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} else {
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u = __builtin_ctzl(u);
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return p[n - 16 + u] - q[n - 16 + u];
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}
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} else {
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u = __builtin_ctzl(u);
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return p[u] - q[u];
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}
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}
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#endif /* __x86_64__ */
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/**
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* Compares memory byte by byte.
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*
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* memcmp n=0 2 nanoseconds
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* memcmp n=1 2 ns/byte 357 mb/s
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* memcmp n=2 1 ns/byte 530 mb/s
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* memcmp n=3 1 ns/byte 631 mb/s
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* 𝗺𝗲𝗺𝗰𝗺𝗽 n=4 1 ns/byte 849 mb/s
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* memcmp n=5 816 ps/byte 1,195 mb/s
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* memcmp n=6 888 ps/byte 1,098 mb/s
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* memcmp n=7 829 ps/byte 1,176 mb/s
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* 𝗺𝗲𝗺𝗰𝗺𝗽 n=8 773 ps/byte 1,261 mb/s
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* memcmp n=9 629 ps/byte 1,551 mb/s
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* memcmp n=15 540 ps/byte 1,805 mb/s
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* 𝗺𝗲𝗺𝗰𝗺𝗽 n=16 211 ps/byte 4,623 mb/s
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* memcmp n=17 268 ps/byte 3,633 mb/s
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* memcmp n=31 277 ps/byte 3,524 mb/s
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* memcmp n=32 153 ps/byte 6,351 mb/s
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* memcmp n=33 179 ps/byte 5,431 mb/s
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* memcmp n=79 148 ps/byte 6,576 mb/s
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* 𝗺𝗲𝗺𝗰𝗺𝗽 n=80 81 ps/byte 11 GB/s
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* memcmp n=128 76 ps/byte 12 GB/s
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* memcmp n=256 60 ps/byte 15 GB/s
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* memcmp n=16384 51 ps/byte 18 GB/s
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* memcmp n=32768 51 ps/byte 18 GB/s
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* memcmp n=131072 52 ps/byte 18 GB/s
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*
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* @return an integer that's (1) equal to zero if `a` is equal to `b`,
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* (2) less than zero if `a` is less than `b`, or (3) greater than
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* zero if `a` is greater than `b`
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* @asyncsignalsafe
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*/
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int memcmp(const void *a, const void *b, size_t n) {
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int c;
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#if defined(__x86_64__) && !defined(__chibicc__)
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unsigned u;
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uint32_t k, i, j;
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uint64_t w, x, y;
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#endif
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const unsigned char *p, *q;
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if ((p = a) == (q = b) || !n)
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return 0;
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if ((c = *p - *q))
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return c;
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#if defined(__x86_64__) && !defined(__chibicc__)
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if (!IsTiny()) {
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if (n <= 16) {
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if (n >= 8) {
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if (!(w = (x = ((uint64_t)p[0] << 000 | (uint64_t)p[1] << 010 |
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(uint64_t)p[2] << 020 | (uint64_t)p[3] << 030 |
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(uint64_t)p[4] << 040 | (uint64_t)p[5] << 050 |
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(uint64_t)p[6] << 060 | (uint64_t)p[7] << 070)) ^
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(y = ((uint64_t)q[0] << 000 | (uint64_t)q[1] << 010 |
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(uint64_t)q[2] << 020 | (uint64_t)q[3] << 030 |
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(uint64_t)q[4] << 040 | (uint64_t)q[5] << 050 |
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(uint64_t)q[6] << 060 | (uint64_t)q[7] << 070)))) {
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p += n - 8;
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q += n - 8;
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if (!(w = (x = ((uint64_t)p[0] << 000 | (uint64_t)p[1] << 010 |
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(uint64_t)p[2] << 020 | (uint64_t)p[3] << 030 |
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(uint64_t)p[4] << 040 | (uint64_t)p[5] << 050 |
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(uint64_t)p[6] << 060 | (uint64_t)p[7] << 070)) ^
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(y = ((uint64_t)q[0] << 000 | (uint64_t)q[1] << 010 |
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(uint64_t)q[2] << 020 | (uint64_t)q[3] << 030 |
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(uint64_t)q[4] << 040 | (uint64_t)q[5] << 050 |
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(uint64_t)q[6] << 060 | (uint64_t)q[7] << 070)))) {
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return 0;
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}
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}
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u = __builtin_ctzll(w);
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u = u & -8;
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return ((x >> u) & 255) - ((y >> u) & 255);
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} else if (n >= 4) {
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if (!(k = (i = ((uint32_t)p[0] << 000 | (uint32_t)p[1] << 010 |
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(uint32_t)p[2] << 020 | (uint32_t)p[3] << 030)) ^
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(j = ((uint32_t)q[0] << 000 | (uint32_t)q[1] << 010 |
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(uint32_t)q[2] << 020 | (uint32_t)q[3] << 030)))) {
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p += n - 4;
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q += n - 4;
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if (!(k = (i = ((uint32_t)p[0] << 000 | (uint32_t)p[1] << 010 |
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(uint32_t)p[2] << 020 | (uint32_t)p[3] << 030)) ^
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(j = ((uint32_t)q[0] << 000 | (uint32_t)q[1] << 010 |
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(uint32_t)q[2] << 020 | (uint32_t)q[3] << 030)))) {
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return 0;
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}
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}
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u = __builtin_ctzl(k);
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u = u & -8;
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return ((i >> u) & 255) - ((j >> u) & 255);
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}
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} else if (LIKELY(X86_HAVE(AVX))) {
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return memcmp_avx(p, q, n);
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} else {
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return memcmp_sse(p, q, n);
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}
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}
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#endif /* __x86_64__ */
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for (; n; ++p, ++q, --n) {
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if ((c = *p - *q)) {
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return c;
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}
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}
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return 0;
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}
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