| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/string.h> |
| #include <linux/export.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; |
| } |
| EXPORT_SYMBOL(strstr); |
