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memmove.S @ dd1be7c

Last change on this file since dd1be7c was e16e8f2, checked in by Edwin Eefting <edwin@datux.nl>, 3 years ago
bootstuff
Property mode set to `100644`
File size: 2.8 KB

Rev	Line
[e16e8f2]	1	/* ----------------------------------------------------------------------- *
	2	*
	3	* Copyright 2008 H. Peter Anvin - All Rights Reserved
	4	* Copyright 2010 Intel Corporation; author: H. Peter Anvin
	5	*
	6	* Permission is hereby granted, free of charge, to any person
	7	* obtaining a copy of this software and associated documentation
	8	* files (the "Software"), to deal in the Software without
	9	* restriction, including without limitation the rights to use,
	10	* copy, modify, merge, publish, distribute, sublicense, and/or
	11	* sell copies of the Software, and to permit persons to whom
	12	* the Software is furnished to do so, subject to the following
	13	* conditions:
	14	*
	15	* The above copyright notice and this permission notice shall
	16	* be included in all copies or substantial portions of the Software.
	17	*
	18	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	19	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
	20	* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	21	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
	22	* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
	23	* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	24	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	25	* OTHER DEALINGS IN THE SOFTWARE.
	26	*
	27	* ----------------------------------------------------------------------- */
	28
	29	/*
	30	* memmove.S
	31	*
	32	* Reasonably efficient memmove, using aligned transfers at least
	33	* for the destination operand.
	34	*/
	35
	36	.globl memmove
	37	.type memmove,@function
	38	.text
	39	memmove:
	40	movl 0xc(%esp),%ecx
	41	movl 0x8(%esp),%edx
	42	movl 0x4(%esp),%eax
	43
	44	jecxz 4f
	45
	46	pushl %esi
	47	pushl %edi
	48	pushl %eax /* Return value */
	49
	50	movl %eax,%edi
	51	movl %edx,%esi
	52
	53	cmpl %edi,%esi
	54	jb 2f
	55
	56	/* source >= dest, forwards move */
	57
	58	/* Initial alignment */
	59	1:
	60	movl %edi,%edx
	61	shrl $1,%edx
	62	jnc 11f
	63	movsb
	64	decl %ecx
	65	11:
	66	movb %cl,%al
	67	cmpl $2,%ecx
	68	jb 13f
	69
	70	shrl $1,%edx
	71	jnc 12f
	72	movsw
	73	subl $2,%ecx
	74	12:
	75	/* Bulk transfer */
	76	movb %cl,%al
	77	shrl $2,%ecx
	78	rep; movsl
	79
	80	/* Final alignment */
	81	testb $2,%al
	82	jz 14f
	83	movsw
	84	13:
	85	14:
	86	testb $1,%al
	87	jz 15f
	88	movsb
	89	15:
	90	/* Common exit stub */
	91	3:
	92	popl %eax /* Return value */
	93	popl %edi
	94	popl %esi
	95	4:
	96	ret
	97
	98
	99	2:
	100	/* source < dest, backwards move if overlap */
	101	leal -1(%ecx,%esi),%eax
	102	cmpl %eax,%edi
	103	ja 1b /* No overlap, after all... */
	104
	105	std
	106	leal -1(%ecx,%edi),%edi
	107	movl %eax,%esi
	108
	109	/* Initial alignment */
	110	movl %edi,%edx
	111	shrl $1,%edx
	112	jc 21f
	113	movsb
	114	decl %ecx
	115	21:
	116	decl %esi
	117	decl %edi
	118	movb %cl,%al
	119	cmpl $2,%ecx
	120	jb 23f
	121	shrl $1,%edx
	122	jc 22f
	123	movsw
	124	subl $2,%ecx
	125	22:
	126	/* Bulk transfer */
	127	subl $2,%esi
	128	subl $2,%edi
	129	movb %cl,%al
	130	shrl $2,%ecx
	131	rep; movsl
	132
	133	/* Final alignment */
	134	addl $2,%esi
	135	addl $2,%edi
	136	testb $2,%al
	137	jz 24f
	138	movsw
	139	23:
	140	24:
	141	incl %esi
	142	incl %edi
	143	testb $1,%al
	144	jz 25f
	145	movsb
	146	25:
	147	cld
	148	jmp 3b
	149
	150	.size memmove, .-memmove

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