mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-07-01 08:48:29 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Make memcmp() and memchr() go fast again

Browse source 
Readahead within the specified size is legal, even if it overlaps a page
boundary; it's the fault of the caller if that causes a segfault.
This commit is contained in:
Justine Tunney 2023-11-29 05:17:21 -08:00
parent 70155df7a9
commit ff955aaa01
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
4 changed files with 137 additions and 49 deletions
Download patch file Download diff file Expand all files Collapse all files

14
libc/intrin/memchr.c
View file

@ -17,11 +17,12 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/dce.h"
#include "libc/intrin/asan.internal.h"
#include "libc/nexgen32e/x86feature.h"
#include "libc/str/str.h"
#ifndef __aarch64__
typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(1)));
static inline const unsigned char *memchr_pure(const unsigned char *s,
unsigned char c, size_t n) {
@ -69,15 +70,8 @@ static inline const unsigned char *memchr_sse(const unsigned char *s,
void *memchr(const void *s, int c, size_t n) {
#if defined(__x86_64__) && !defined(__chibicc__)
const void *r;
const unsigned char *p = (const unsigned char *)s;
while (n && ((intptr_t)p & 15)) {
if (*p == (unsigned char)c) {
return (void *)p;
}
++p;
--n;
}
r = memchr_sse(p, c, n);
if (IsAsan()) __asan_verify(s, n);
r = memchr_sse(s, c, n);
return (void *)r;
#else
return (void *)memchr_pure(s, c, n);