diff options
Diffstat (limited to 'libc/string/i386/memchr.c')
| -rw-r--r-- | libc/string/i386/memchr.c | 50 |
1 files changed, 37 insertions, 13 deletions
diff --git a/libc/string/i386/memchr.c b/libc/string/i386/memchr.c index 5c64445e0..c2fc44b4a 100644 --- a/libc/string/i386/memchr.c +++ b/libc/string/i386/memchr.c @@ -33,19 +33,43 @@ #include <string.h> #undef memchr -void *memchr(const void *cs, int c, size_t count) +//#define memchr TESTING +void *memchr(const void *s, int c, size_t count) { - int d0; - register void * __res; - if (!count) - return NULL; - __asm__ __volatile__( - "repne\n\t" - "scasb\n\t" - "je 1f\n\t" - "movl $1,%0\n" - "1:\tdecl %0" - :"=D" (__res), "=&c" (d0) : "a" (c),"0" (cs),"1" (count)); - return __res; + void *edi; + int ecx; + __asm__ __volatile__( + " jecxz 1f\n" + " repne; scasb\n" + " leal -1(%%edi), %%edi\n" + " je 2f\n" + "1:\n" + " xorl %%edi, %%edi\n" /* NULL */ + "2:\n" + : "=&D" (edi), "=&c" (ecx) + : "a" (c), "0" (s), "1" (count) + /* : no clobbers */ + ); + return edi; } +#ifndef memchr libc_hidden_def(memchr) +#else +/* Uncomment TESTING, gcc -D_GNU_SOURCE -m32 -Os memchr.c -o memchr + * and run ./memchr + */ +int main() +{ + static const char str[] = "abc.def"; + printf((char*)memchr(str, '.',-2) - str == 3 ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str, '.',-1) - str == 3 ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str, '.', 0) == NULL ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str, '.', 1) == NULL ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str, '.', 2) == NULL ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str, '.', 3) == NULL ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str, '.', 4) - str == 3 ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str, '.', 5) - str == 3 ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str+3, '.', 0) == NULL ? "ok\n" : "BAD!\n"); + printf((char*)memchr(str+3, '.', 5) - str == 3 ? "ok\n" : "BAD!\n"); +} +#endif |