summaryrefslogtreecommitdiffstats
path: root/arch/mn10300/lib/memcpy.S
blob: 25fb9bb2604f521690d6b317a7db370e646fef97 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
/* MN10300 Optimised simple memory to memory copy
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#include <asm/cache.h>

        .section .text
        .balign	L1_CACHE_BYTES

###############################################################################
#
# void *memcpy(void *dst, const void *src, size_t n)
#
###############################################################################
	.globl	memcpy
        .type	memcpy,@function
memcpy:
	movm	[d2,d3],(sp)
	mov	d0,(12,sp)
	mov	d1,(16,sp)
	mov	(20,sp),d2			# count
	mov	d0,a0				# dst
	mov	d1,a1				# src
	mov	d0,e3				# the return value

	cmp	+0,d2
	beq	memcpy_done			# return if zero-length copy

	# see if the three parameters are all four-byte aligned
	or	d0,d1,d3
	or	d2,d3
	and	+3,d3
	bne	memcpy_1			# jump if not

	# we want to transfer as much as we can in chunks of 32 bytes
	cmp	+31,d2
	bls	memcpy_4_remainder		# 4-byte aligned remainder

	movm	[exreg1],(sp)
	add	-32,d2
	mov	+32,d3

memcpy_4_loop:
	mov	(a1+),d0
	mov	(a1+),d1
	mov	(a1+),e0
	mov	(a1+),e1
	mov	(a1+),e4
	mov	(a1+),e5
	mov	(a1+),e6
	mov	(a1+),e7
	mov	d0,(a0+)
	mov	d1,(a0+)
	mov	e0,(a0+)
	mov	e1,(a0+)
	mov	e4,(a0+)
	mov	e5,(a0+)
	mov	e6,(a0+)
	mov	e7,(a0+)

	sub	d3,d2
	bcc	memcpy_4_loop

	movm	(sp),[exreg1]
	add	d3,d2
	beq	memcpy_4_no_remainder

memcpy_4_remainder:
	# cut 4-7 words down to 0-3
	cmp	+16,d2
	bcs	memcpy_4_three_or_fewer_words
	mov	(a1+),d0
	mov	(a1+),d1
	mov	(a1+),e0
	mov	(a1+),e1
	mov	d0,(a0+)
	mov	d1,(a0+)
	mov	e0,(a0+)
	mov	e1,(a0+)
	add	-16,d2
	beq	memcpy_4_no_remainder

	# copy the remaining 1, 2 or 3 words
memcpy_4_three_or_fewer_words:
	cmp	+8,d2
	bcs	memcpy_4_one_word
	beq	memcpy_4_two_words
	mov	(a1+),d0
	mov	d0,(a0+)
memcpy_4_two_words:
	mov	(a1+),d0
	mov	d0,(a0+)
memcpy_4_one_word:
	mov	(a1+),d0
	mov	d0,(a0+)

memcpy_4_no_remainder:
	# check we copied the correct amount
	# TODO: REMOVE CHECK
	sub	e3,a0,d2
	mov	(20,sp),d1
	cmp	d2,d1
	beq	memcpy_done
	break
	break
	break

memcpy_done:
	mov	e3,a0
	ret	[d2,d3],8

	# handle misaligned copying
memcpy_1:
	add	-1,d2
	mov	+1,d3
	setlb					# setlb requires the next insns
						# to occupy exactly 4 bytes

	sub	d3,d2
	movbu	(a1),d0
	movbu	d0,(a0)
	add_add	d3,a1,d3,a0
	lcc

	mov	e3,a0
	ret	[d2,d3],8

memcpy_end:
	.size	memcpy, memcpy_end-memcpy