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#

# Copyright (c) 2006 Martin Decky

# All rights reserved.

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions

# are met:

#

# - Redistributions of source code must retain the above copyright

#   notice, this list of conditions and the following disclaimer.

# - Redistributions in binary form must reproduce the above copyright

#   notice, this list of conditions and the following disclaimer in the

#   documentation and/or other materials provided with the distribution.

# - The name of the author may not be used to endorse or promote products

#   derived from this software without specific prior written permission.

#

# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#

#include "regname.h"

.set noat

.set noreorder

.set nomacro

.text

.global halt

.global memcpy

.global jump_to_kernel

halt:

	b halt

	nop

memcpy:

	addiu	$v0,$a1,3

	li	$v1,-4			# 0xfffffffffffffffc

	and	$v0,$v0,$v1

	beq	$a1,$v0,3f

	move	$t0,$a0

0:

	beq	$a2,$zero,2f

	move	$a3,$zero

1:

	addu	$v0,$a1,$a3

	lbu	$a0,0($v0)

	addu	$v1,$t0,$a3

	addiu	$a3,$a3,1

	bne	$a3,$a2,1b

	sb	$a0,0($v1)

2:

	jr	$ra

	move	$v0,$a1

3:

	addiu	$v0,$a0,3

	and	$v0,$v0,$v1

	bne	$a0,$v0,0b

	srl	$t1,$a2,2

	beq	$t1,$zero,5f

	move	$a3,$zero

	move	$a3,$zero

	move	$a0,$zero

4:

	addu	$v0,$a1,$a0

	lw	$v1,0($v0)

	addiu	$a3,$a3,1

	addu	$v0,$t0,$a0

	sw	$v1,0($v0)

	bne	$a3,$t1,4b

	addiu	$a0,$a0,4

5:

	andi	$a2,$a2,0x3

	beq	$a2,$zero,2b

	nop

	sll	$v0,$a3,2

	addu	$t1,$v0,$t0

	move	$a3,$zero

	addu	$t0,$v0,$a1

6:

	addu	$v0,$t0,$a3

	lbu	$a0,0($v0)

	addu	$v1,$t1,$a3

	addiu	$a3,$a3,1

	bne	$a3,$a2,6b

	sb	$a0,0($v1)

	jr	$ra

	move	$v0,$a1

jump_to_kernel:

	#

	# TODO

	# Make sure that the I-cache, D-cache and memory are mutually coherent

	# before passing control to the copied code.

	#

	j $a0

	nop