| /* $OpenBSD: strcat.S,v 1.8 2005/08/07 11:30:38 espie Exp $ */ |
| /* |
| * Written by J.T. Conklin <jtc@netbsd.org>. |
| * Public domain. |
| */ |
| |
| #include <machine/asm.h> |
| |
| #if defined(APIWARN) |
| #APP |
| .section .gnu.warning.strcat |
| .ascii "warning: strcat() is almost always misused, please use strlcat()" |
| #NO_APP |
| #endif |
| |
| /* |
| * NOTE: I've unrolled the loop eight times: large enough to make a |
| * significant difference, and small enough not to totally trash the |
| * cache. |
| */ |
| |
| ENTRY(strcat) |
| pushl %edi /* save edi */ |
| movl 8(%esp),%edi /* dst address */ |
| movl 12(%esp),%edx /* src address */ |
| pushl %edi /* push destination address */ |
| |
| cld /* set search forward */ |
| xorl %eax,%eax /* set search for null terminator */ |
| movl $-1,%ecx /* set search for lots of characters */ |
| repne /* search! */ |
| scasb |
| |
| leal -1(%edi),%ecx /* correct dst address */ |
| |
| .align 2,0x90 |
| L1: movb (%edx),%al /* unroll loop, but not too much */ |
| movb %al,(%ecx) |
| testb %al,%al |
| jz L2 |
| movb 1(%edx),%al |
| movb %al,1(%ecx) |
| testb %al,%al |
| jz L2 |
| movb 2(%edx),%al |
| movb %al,2(%ecx) |
| testb %al,%al |
| jz L2 |
| movb 3(%edx),%al |
| movb %al,3(%ecx) |
| testb %al,%al |
| jz L2 |
| movb 4(%edx),%al |
| movb %al,4(%ecx) |
| testb %al,%al |
| jz L2 |
| movb 5(%edx),%al |
| movb %al,5(%ecx) |
| testb %al,%al |
| jz L2 |
| movb 6(%edx),%al |
| movb %al,6(%ecx) |
| testb %al,%al |
| jz L2 |
| movb 7(%edx),%al |
| movb %al,7(%ecx) |
| addl $8,%edx |
| addl $8,%ecx |
| testb %al,%al |
| jnz L1 |
| L2: popl %eax /* pop destination address */ |
| popl %edi /* restore edi */ |
| ret |
| END(strcat) |
