root/arch/x86/lib/strstr_32.c

DEFINITIONS

1. strstr

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/string.h>
   3 #include <linux/export.h>
   4 
   5 char *strstr(const char *cs, const char *ct)
   6 {
   7 int     d0, d1;
   8 register char *__res;
   9 __asm__ __volatile__(
  10         "movl %6,%%edi\n\t"
  11         "repne\n\t"
  12         "scasb\n\t"
  13         "notl %%ecx\n\t"
  14         "decl %%ecx\n\t"        /* NOTE! This also sets Z if searchstring='' */
  15         "movl %%ecx,%%edx\n"
  16         "1:\tmovl %6,%%edi\n\t"
  17         "movl %%esi,%%eax\n\t"
  18         "movl %%edx,%%ecx\n\t"
  19         "repe\n\t"
  20         "cmpsb\n\t"
  21         "je 2f\n\t"             /* also works for empty string, see above */
  22         "xchgl %%eax,%%esi\n\t"
  23         "incl %%esi\n\t"
  24         "cmpb $0,-1(%%eax)\n\t"
  25         "jne 1b\n\t"
  26         "xorl %%eax,%%eax\n\t"
  27         "2:"
  28         : "=a" (__res), "=&c" (d0), "=&S" (d1)
  29         : "0" (0), "1" (0xffffffff), "2" (cs), "g" (ct)
  30         : "dx", "di");
  31 return __res;
  32 }
  33 EXPORT_SYMBOL(strstr);