1/* ----------------------------------------------------------------------- * 2 * 3 * Copyright 2008 H. Peter Anvin - All Rights Reserved 4 * 5 * Permission is hereby granted, free of charge, to any person 6 * obtaining a copy of this software and associated documentation 7 * files (the "Software"), to deal in the Software without 8 * restriction, including without limitation the rights to use, 9 * copy, modify, merge, publish, distribute, sublicense, and/or 10 * sell copies of the Software, and to permit persons to whom 11 * the Software is furnished to do so, subject to the following 12 * conditions: 13 * 14 * The above copyright notice and this permission notice shall 15 * be included in all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 24 * OTHER DEALINGS IN THE SOFTWARE. 25 * 26 * ----------------------------------------------------------------------- */ 27 28/* 29 * memcpy.S 30 * 31 * Reasonably efficient memcpy, using aligned transfers at least 32 * for the destination operand. 33 */ 34 35 .text 36 .globl memcpy 37 .type memcpy, @function 38memcpy: 39 jecxz 1f 40 41 pushl %esi 42 pushl %edi 43 pushl %eax /* Return value */ 44 45 movl %eax,%edi 46 movl %edx,%esi 47 48 /* Initial alignment */ 49 movl %edi,%edx 50 shrl $1,%edx 51 jnc 11f 52 movsb 53 decl %ecx 5411: 55 movb %cl,%al 56 cmpl $2,%ecx 57 jb 13f 58 59 shrl $1,%edx 60 jnc 12f 61 movsw 62 subl $2,%ecx 6312: 64 /* Bulk transfer */ 65 movb %cl,%al 66 shrl $2,%ecx 67 rep; movsl 68 69 /* Final alignment */ 70 testb $2,%al 71 jz 14f 72 movsw 7313: 7414: 75 testb $1,%al 76 jz 15f 77 movsb 7815: 79 80 popl %eax /* Return value */ 81 popl %edi 82 popl %esi 831: 84 ret 85 86 .size memcpy, .-memcpy 87