1/* $OpenBSD: memmove.S,v 1.7 2014/11/29 18:51:23 tedu Exp $ */ 2 3/*- 4 * Copyright (c) 1993, 1994, 1995 Charles M. Hannum. All rights reserved. 5 * Copyright (c) 1990 The Regents of the University of California. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * William Jolitz. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36#include <machine/param.h> 37#include <machine/asm.h> 38 39/* 40 * Emulate bcopy() by swapping the first two arguments, and jumping 41 * into memmove(), which handles overlapping regions. 42 */ 43ENTRY(bcopy) 44 pushl %esi 45 pushl %edi 46 movl 12(%esp),%esi 47 movl 16(%esp),%edi 48 jmp docopy 49 50/* 51 * memmove(caddr_t dst, caddr_t src, size_t len); 52 * Copy len bytes, coping with overlapping space. 53 */ 54ENTRY(memmove) 55 pushl %esi 56 pushl %edi 57 movl 12(%esp),%edi 58 movl 16(%esp),%esi 59docopy: 60 movl 20(%esp),%ecx 61 movl %edi,%eax 62 subl %esi,%eax 63 cmpl %ecx,%eax # overlapping? 64 jb 1f 65 jmp docopyf # nope 66/* 67 * memcpy() doesn't worry about overlap and always copies forward 68 */ 69ENTRY(memcpy) 70 pushl %esi 71 pushl %edi 72 movl 12(%esp),%edi 73 movl 16(%esp),%esi 74 movl 20(%esp),%ecx 75docopyf: 76 movl %edi,%eax # setup return value for memcpy/memmove 77 shrl $2,%ecx # copy by 32-bit words 78 rep 79 movsl 80 movl 20(%esp),%ecx 81 andl $3,%ecx # any bytes left? 82 rep 83 movsb 84 popl %edi 85 popl %esi 86 ret 87 88 _ALIGN_TEXT 891: movl %edi,%eax # setup return value for memmove 90 addl %ecx,%edi # copy backward 91 addl %ecx,%esi 92 std 93 andl $3,%ecx # any fractional bytes? 94 decl %edi 95 decl %esi 96 rep 97 movsb 98 movl 20(%esp),%ecx # copy remainder by 32-bit words 99 shrl $2,%ecx 100 subl $3,%esi 101 subl $3,%edi 102 rep 103 movsl 104 popl %edi 105 popl %esi 106 cld 107 ret 108 109