1/* $OpenBSD: memmove.S,v 1.6 2015/08/31 02:53:56 guenther 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 "SYS.h" 37 38/* 39 * Emulate bcopy() by swapping the first two arguments, and jumping 40 * into memmove(), which handles overlapping regions. 41 */ 42ENTRY(bcopy) 43 pushl %esi 44 pushl %edi 45 movl 12(%esp),%esi 46 movl 16(%esp),%edi 47 jmp docopy 48 49/* 50 * memmove(caddr_t dst, caddr_t src, size_t len); 51 * Copy len bytes, coping with overlapping space. 52 */ 53ENTRY(memmove) 54 pushl %esi 55 pushl %edi 56 movl 12(%esp),%edi 57 movl 16(%esp),%esi 58docopy: 59 movl 20(%esp),%ecx 60 movl %edi,%eax 61 subl %esi,%eax 62 cmpl %ecx,%eax # overlapping? 63 jb 1f 64 jmp docopyf # nope 65/* 66 * memcpy() doesn't worry about overlap and always copies forward 67 */ 68// ENTRY(memcpy) 69 pushl %esi 70 pushl %edi 71 movl 12(%esp),%edi 72 movl 16(%esp),%esi 73 movl 20(%esp),%ecx 74docopyf: 75 movl %edi,%eax # setup return value for memcpy/memmove 76 shrl $2,%ecx # copy by 32-bit words 77 rep 78 movsl 79 movl 20(%esp),%ecx 80 andl $3,%ecx # any bytes left? 81 rep 82 movsb 83 popl %edi 84 popl %esi 85 ret 86 87 _ALIGN_TEXT 881: movl %edi,%eax # setup return value for memmove 89 addl %ecx,%edi # copy backward 90 addl %ecx,%esi 91 std 92 andl $3,%ecx # any fractional bytes? 93 decl %edi 94 decl %esi 95 rep 96 movsb 97 movl 20(%esp),%ecx # copy remainder by 32-bit words 98 shrl $2,%ecx 99 subl $3,%esi 100 subl $3,%edi 101 rep 102 movsl 103 popl %edi 104 popl %esi 105 cld 106 ret 107END_STRONG(memmove) 108END_WEAK(bcopy) 109