1/* 2 * Written by J.T. Conklin <jtc@netbsd.org>. 3 * Public domain. 4 */ 5 6#include <machine/asm.h> 7 8#if defined(LIBC_SCCS) 9 RCSID("$NetBSD: strcat.S,v 1.8 1995/04/28 22:58:09 jtc Exp $") 10#endif 11 12/* 13 * NOTE: I've unrolled the loop eight times: large enough to make a 14 * significant difference, and small enough not to totally trash the 15 * cache. 16 */ 17 18ENTRY(strcat) 19 pushl %edi /* save edi */ 20 movl 8(%esp),%edi /* dst address */ 21 movl 12(%esp),%edx /* src address */ 22 pushl %edi /* push destination address */ 23 24 cld /* set search forward */ 25 xorl %eax,%eax /* set search for null terminator */ 26 movl $-1,%ecx /* set search for lots of characters */ 27 repne /* search! */ 28 scasb 29 30 leal -1(%edi),%ecx /* correct dst address */ 31 32 .align 2,0x90 33L1: movb (%edx),%al /* unroll loop, but not too much */ 34 movb %al,(%ecx) 35 testb %al,%al 36 jz L2 37 movb 1(%edx),%al 38 movb %al,1(%ecx) 39 testb %al,%al 40 jz L2 41 movb 2(%edx),%al 42 movb %al,2(%ecx) 43 testb %al,%al 44 jz L2 45 movb 3(%edx),%al 46 movb %al,3(%ecx) 47 testb %al,%al 48 jz L2 49 movb 4(%edx),%al 50 movb %al,4(%ecx) 51 testb %al,%al 52 jz L2 53 movb 5(%edx),%al 54 movb %al,5(%ecx) 55 testb %al,%al 56 jz L2 57 movb 6(%edx),%al 58 movb %al,6(%ecx) 59 testb %al,%al 60 jz L2 61 movb 7(%edx),%al 62 movb %al,7(%ecx) 63 addl $8,%edx 64 addl $8,%ecx 65 testb %al,%al 66 jnz L1 67L2: popl %eax /* pop destination address */ 68 popl %edi /* restore edi */ 69 ret 70