blob: 20b07b62b77c38bc96bc7a0dc66fef59b98f1f02 [file] [log] [blame]
David Howellsb920de12008-02-08 04:19:31 -08001/* MN10300 Optimised simple memory to memory copy, with support for overlapping
2 * regions
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public Licence
9 * as published by the Free Software Foundation; either version
10 * 2 of the Licence, or (at your option) any later version.
11 */
12#include <asm/cache.h>
13
14 .section .text
15 .balign L1_CACHE_BYTES
16
17###############################################################################
18#
19# void *memmove(void *dst, const void *src, size_t n)
20#
21###############################################################################
22 .globl memmove
23 .type memmove,@function
24memmove:
25 # fall back to memcpy if dst < src to work bottom up
26 cmp d1,d0
27 bcs memmove_memcpy
28
29 # work top down
30 movm [d2,d3],(sp)
31 mov d0,(12,sp)
32 mov d1,(16,sp)
33 mov (20,sp),d2 # count
34 add d0,d2,a0 # dst end
35 add d1,d2,a1 # src end
36 mov d0,e3 # the return value
37
38 cmp +0,d2
39 beq memmove_done # return if zero-length copy
40
41 # see if the three parameters are all four-byte aligned
42 or d0,d1,d3
43 or d2,d3
44 and +3,d3
45 bne memmove_1 # jump if not
46
47 # we want to transfer as much as we can in chunks of 32 bytes
48 add -4,a1
49 cmp +31,d2
50 bls memmove_4_remainder # 4-byte aligned remainder
51
52 add -32,d2
53 mov +32,d3
54
55memmove_4_loop:
56 mov (a1),d0
57 sub_sub +4,a1,+4,a0
58 mov d0,(a0)
59 mov (a1),d1
60 sub_sub +4,a1,+4,a0
61 mov d1,(a0)
62
63 mov (a1),d0
64 sub_sub +4,a1,+4,a0
65 mov d0,(a0)
66 mov (a1),d1
67 sub_sub +4,a1,+4,a0
68 mov d1,(a0)
69
70 mov (a1),d0
71 sub_sub +4,a1,+4,a0
72 mov d0,(a0)
73 mov (a1),d1
74 sub_sub +4,a1,+4,a0
75 mov d1,(a0)
76
77 mov (a1),d0
78 sub_sub +4,a1,+4,a0
79 mov d0,(a0)
80 mov (a1),d1
81 sub_sub +4,a1,+4,a0
82 mov d1,(a0)
83
84 sub d3,d2
85 bcc memmove_4_loop
86
87 add d3,d2
88 beq memmove_4_no_remainder
89
90memmove_4_remainder:
91 # cut 4-7 words down to 0-3
92 cmp +16,d2
93 bcs memmove_4_three_or_fewer_words
94 mov (a1),d0
95 sub_sub +4,a1,+4,a0
96 mov d0,(a0)
97 mov (a1),d1
98 sub_sub +4,a1,+4,a0
99 mov d1,(a0)
100 mov (a1),e0
101 sub_sub +4,a1,+4,a0
102 mov e0,(a0)
103 mov (a1),e1
104 sub_sub +4,a1,+4,a0
105 mov e1,(a0)
106 add -16,d2
107 beq memmove_4_no_remainder
108
109 # copy the remaining 1, 2 or 3 words
110memmove_4_three_or_fewer_words:
111 cmp +8,d2
112 bcs memmove_4_one_word
113 beq memmove_4_two_words
114 mov (a1),d0
115 sub_sub +4,a1,+4,a0
116 mov d0,(a0)
117memmove_4_two_words:
118 mov (a1),d0
119 sub_sub +4,a1,+4,a0
120 mov d0,(a0)
121memmove_4_one_word:
122 mov (a1),d0
123 sub_sub +4,a1,+4,a0
124 mov d0,(a0)
125
126memmove_4_no_remainder:
127 # check we copied the correct amount
128 # TODO: REMOVE CHECK
129 sub e3,a0,d2
130 beq memmove_done
131 break
132 break
133 break
134
135memmove_done:
136 mov e3,a0
137 ret [d2,d3],8
138
139 # handle misaligned copying
140memmove_1:
141 add -1,a1
142 add -1,d2
143 mov +1,d3
144 setlb # setlb requires the next insns
145 # to occupy exactly 4 bytes
146
147 sub d3,d2
148 movbu (a1),d0
149 sub_sub d3,a1,d3,a0
150 movbu d0,(a0)
151 lcc
152
153 mov e3,a0
154 ret [d2,d3],8
155
156memmove_memcpy:
157 jmp memcpy
158
159memmove_end:
160 .size memmove, memmove_end-memmove