arch/i386/lib/strstr.c

   1 #include <linux/string.h>
   2
   3 char * strstr(const char * cs,const char * ct)
   4 {
   5 int     d0, d1;
   6 register char * __res;
   7 __asm__ __volatile__(
   8         "movl %6,%%edi\n\t"
   9         "repne\n\t"
  10         "scasb\n\t"
  11         "notl %%ecx\n\t"
  12         "decl %%ecx\n\t"        /* NOTE! This also sets Z if searchstring='' */
  13         "movl %%ecx,%%edx\n"
  14         "1:\tmovl %6,%%edi\n\t"
  15         "movl %%esi,%%eax\n\t"
  16         "movl %%edx,%%ecx\n\t"
  17         "repe\n\t"
  18         "cmpsb\n\t"
  19         "je 2f\n\t"             /* also works for empty string, see above */
  20         "xchgl %%eax,%%esi\n\t"
  21         "incl %%esi\n\t"
  22         "cmpb $0,-1(%%eax)\n\t"
  23         "jne 1b\n\t"
  24         "xorl %%eax,%%eax\n\t"
  25         "2:"
  26         :"=a" (__res), "=&c" (d0), "=&S" (d1)
  27         :"0" (0), "1" (0xffffffff), "2" (cs), "g" (ct)
  28         :"dx", "di");
  29 return __res;
  30 }
  31