mirror of
https://github.com/torvalds/linux.git
synced 2024-12-09 04:31:39 +00:00
32 lines
674 B
C
32 lines
674 B
C
|
#include <linux/string.h>
|
||
|
|
||
|
char * strstr(const char * cs,const char * ct)
|
||
|
{
|
||
|
int d0, d1;
|
||
|
register char * __res;
|
||
|
__asm__ __volatile__(
|
||
|
"movl %6,%%edi\n\t"
|
||
|
"repne\n\t"
|
||
|
"scasb\n\t"
|
||
|
"notl %%ecx\n\t"
|
||
|
"decl %%ecx\n\t" /* NOTE! This also sets Z if searchstring='' */
|
||
|
"movl %%ecx,%%edx\n"
|
||
|
"1:\tmovl %6,%%edi\n\t"
|
||
|
"movl %%esi,%%eax\n\t"
|
||
|
"movl %%edx,%%ecx\n\t"
|
||
|
"repe\n\t"
|
||
|
"cmpsb\n\t"
|
||
|
"je 2f\n\t" /* also works for empty string, see above */
|
||
|
"xchgl %%eax,%%esi\n\t"
|
||
|
"incl %%esi\n\t"
|
||
|
"cmpb $0,-1(%%eax)\n\t"
|
||
|
"jne 1b\n\t"
|
||
|
"xorl %%eax,%%eax\n\t"
|
||
|
"2:"
|
||
|
:"=a" (__res), "=&c" (d0), "=&S" (d1)
|
||
|
:"0" (0), "1" (0xffffffff), "2" (cs), "g" (ct)
|
||
|
:"dx", "di");
|
||
|
return __res;
|
||
|
}
|
||
|
|