memcpy.s

MIPS下的boottloader yamon 的源代码

/************************************************************************
 *
 *  memcpy.S
 *
 *  Memory copy
 *
 *
 * ######################################################################
 *
 * Copyright (c) 1999-2000 MIPS Technologies, Inc. All rights reserved. 
 * 
 * Unpublished rights reserved under the Copyright Laws of the United States of 
 * America. 
 * 
 * This document contains information that is proprietary to MIPS Technologies, 
 * Inc. ("MIPS Technologies"). Any copying, modifying or use of this information 
 * (in whole or in part) which is not expressly permitted in writing by MIPS 
 * Technologies or a contractually-authorized third party is strictly 
 * prohibited. At a minimum, this information is protected under unfair 
 * competition laws and the expression of the information contained herein is 
 * protected under federal copyright laws. Violations thereof may result in 
 * criminal penalties and fines. 
 * MIPS Technologies or any contractually-authorized third party reserves the 
 * right to change the information contained in this document to improve 
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 * liability arising out of the application or use of this information. Any 
 * license under patent rights or any other intellectual property rights owned 
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 * or any contractually-authorized third party in a separate license agreement 
 * between the parties. 
 * The information contained in this document constitutes one or more of the 
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 ************************************************************************/


/************************************************************************
 *  Include files
 ************************************************************************/

#include <mips.h>


/************************************************************************
 *  Definitions
 ************************************************************************/

/************************************************************************
 *  Public variables
 ************************************************************************/

/************************************************************************
 *  Static variables
 ************************************************************************/

/************************************************************************
 *  Implementation : Public functions
 ************************************************************************/

/* 
 * This routine could be optimized for MIPS64. The current code only
 * uses MIPS32 instructions.
 */	

#ifdef EB
#  define LWHI	lwl		/* high part is left in big-endian	*/
#  define SWHI	swl		/* high part is left in big-endian	*/
#  define LWLO	lwr		/* low part is right in big-endian	*/
#  define SWLO	swr		/* low part is right in big-endian	*/
#else
#  define LWHI	lwr		/* high part is right in little-endian	*/
#  define SWHI	swr		/* high part is right in little-endian	*/
#  define LWLO	lwl		/* low part is left in big-endian	*/
#  define SWLO	swl		/* low part is left in big-endian	*/
#endif


LEAF( memcpy )

	.set	noreorder
	.set	noat

	slti	AT,a2,8
	bne	AT,zero,last8
	move	v0,a0
	xor	t2,a1,a0
	andi	t2,t2,0x3		# a0/a1 displacement
	bne	t2,zero,shift
	subu	v1,zero,a1
	andi	v1,v1,0x3
	beq	v1,zero,chk8w
	subu	a2,a2,v1
	LWHI	t2,0(a1)
	addu	a1,a1,v1
	SWHI	t2,0(a0)
	addu	a0,a0,v1
chk8w:	andi	t2,a2,0x1f
	beq	a2,t2,chk1w
	subu	a3,a2,t2
	addu	a3,a3,a1
loop8w:	lw	t7,0(a1)
	lw	v1,4(a1)
	lw	t0,8(a1)
	lw	t1,12(a1)
	lw	t3,16(a1)
	lw	t4,20(a1)
	lw	t5,24(a1)
	lw	t6,28(a1)
	sw	t7,0(a0)
	sw	v1,4(a0)
	sw	t0,8(a0)
	sw	t1,12(a0)
	sw	t3,16(a0)
	addiu	a1,a1,32
	sw	t4,20(a0)
	sw	t5,24(a0)
	addiu	a0,a0,32
	bne	a1,a3,loop8w
	sw	t6,-4(a0)
	move	a2,t2
chk1w:	andi	t2,a2,0x3
	beq	a2,t2,last8
	subu	a3,a2,t2
	addu	a3,a3,a1
loop1w:	lw	t3,0(a1)
	addiu	a1,a1,4
	addiu	a0,a0,4
	bne	a1,a3,loop1w
	sw	t3,-4(a0)
	move	a2,t2
last8:	blez	a2,last8e
	addu	a3,a2,a1
last8l:	lb	t2,0(a1)
	addiu	a1,a1,1
	addiu	a0,a0,1
	bne	a1,a3,last8l
	sb	t2,-1(a0)
last8e:	j	ra
	nop
shift:	subu	a3,zero,a0
	andi	a3,a3,0x3
	beq	a3,zero,shift1
	subu	a2,a2,a3	# bytes left
	LWHI	t2,0(a1)
	LWLO	t2,3(a1)
	addu	a1,a1,a3
	SWHI	t2,0(a0)
	addu	a0,a0,a3
shift1:	andi	t2,a2,0x3
	subu	a3,a2,t2
	addu	a3,a3,a1
shifth:	LWHI	t3,0(a1)
	LWLO	t3,3(a1)
	addiu	a1,a1,4
	addiu	a0,a0,4
	bne	a1,a3,shifth
	sw	t3,-4(a0)
	b	last8
	move	a2,t2

	.set	at
	.set	reorder

END( memcpy )


/************************************************************************
 *  Implementation : Static functions
 ************************************************************************/