1/* $OpenBSD: memmove.S,v 1.8 2022/12/04 08:22:13 tb 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 "DEFS.h" 37 38/* 39 * Emulate bcopy() by swapping the first two arguments, and jumping 40 * into memmove(), which handles overlapping regions. 41 */ 42ENTRY_NB(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#ifdef memcpy_in_asm 65 jmp docopyf # nope 66 67/* 68 * memcpy() doesn't worry about overlap and always copies forward 69 */ 70ENTRY(memcpy) 71 pushl %esi 72 pushl %edi 73 movl 12(%esp),%edi 74 movl 16(%esp),%esi 75 movl 20(%esp),%ecx 76docopyf: 77#endif 78 movl %edi,%eax # setup return value for memcpy/memmove 79 shrl $2,%ecx # copy by 32-bit words 80 rep 81 movsl 82 movl 20(%esp),%ecx 83 andl $3,%ecx # any bytes left? 84 rep 85 movsb 86 popl %edi 87 popl %esi 88 ret 89 90 _ALIGN_TEXT 911: movl %edi,%eax # setup return value for memmove 92 addl %ecx,%edi # copy backward 93 addl %ecx,%esi 94 std 95 andl $3,%ecx # any fractional bytes? 96 decl %edi 97 decl %esi 98 rep 99 movsb 100 movl 20(%esp),%ecx # copy remainder by 32-bit words 101 shrl $2,%ecx 102 subl $3,%esi 103 subl $3,%edi 104 rep 105 movsl 106 popl %edi 107 popl %esi 108 cld 109 ret 110#ifdef memcpy_in_asm 111END_BUILTIN(memcpy) 112#endif 113END_BUILTIN(memmove) 114END_WEAK(bcopy) 115