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David Howellsb920de12008-02-08 04:19:31 -08001/* MN10300 Optimised simple memory to memory copy
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11#include <asm/cache.h>
12
13 .section .text
14 .balign L1_CACHE_BYTES
15
16###############################################################################
17#
18# void *memcpy(void *dst, const void *src, size_t n)
19#
20###############################################################################
21 .globl memcpy
22 .type memcpy,@function
23memcpy:
24 movm [d2,d3],(sp)
25 mov d0,(12,sp)
26 mov d1,(16,sp)
27 mov (20,sp),d2 # count
28 mov d0,a0 # dst
29 mov d1,a1 # src
30 mov d0,e3 # the return value
31
32 cmp +0,d2
33 beq memcpy_done # return if zero-length copy
34
35 # see if the three parameters are all four-byte aligned
36 or d0,d1,d3
37 or d2,d3
38 and +3,d3
39 bne memcpy_1 # jump if not
40
41 # we want to transfer as much as we can in chunks of 32 bytes
42 cmp +31,d2
43 bls memcpy_4_remainder # 4-byte aligned remainder
44
45 movm [exreg1],(sp)
46 add -32,d2
47 mov +32,d3
48
49memcpy_4_loop:
50 mov (a1+),d0
51 mov (a1+),d1
52 mov (a1+),e0
53 mov (a1+),e1
54 mov (a1+),e4
55 mov (a1+),e5
56 mov (a1+),e6
57 mov (a1+),e7
58 mov d0,(a0+)
59 mov d1,(a0+)
60 mov e0,(a0+)
61 mov e1,(a0+)
62 mov e4,(a0+)
63 mov e5,(a0+)
64 mov e6,(a0+)
65 mov e7,(a0+)
66
67 sub d3,d2
68 bcc memcpy_4_loop
69
70 movm (sp),[exreg1]
71 add d3,d2
72 beq memcpy_4_no_remainder
73
74memcpy_4_remainder:
75 # cut 4-7 words down to 0-3
76 cmp +16,d2
77 bcs memcpy_4_three_or_fewer_words
78 mov (a1+),d0
79 mov (a1+),d1
80 mov (a1+),e0
81 mov (a1+),e1
82 mov d0,(a0+)
83 mov d1,(a0+)
84 mov e0,(a0+)
85 mov e1,(a0+)
86 add -16,d2
87 beq memcpy_4_no_remainder
88
89 # copy the remaining 1, 2 or 3 words
90memcpy_4_three_or_fewer_words:
91 cmp +8,d2
92 bcs memcpy_4_one_word
93 beq memcpy_4_two_words
94 mov (a1+),d0
95 mov d0,(a0+)
96memcpy_4_two_words:
97 mov (a1+),d0
98 mov d0,(a0+)
99memcpy_4_one_word:
100 mov (a1+),d0
101 mov d0,(a0+)
102
103memcpy_4_no_remainder:
104 # check we copied the correct amount
105 # TODO: REMOVE CHECK
106 sub e3,a0,d2
107 mov (20,sp),d1
108 cmp d2,d1
109 beq memcpy_done
110 break
111 break
112 break
113
114memcpy_done:
115 mov e3,a0
116 ret [d2,d3],8
117
118 # handle misaligned copying
119memcpy_1:
120 add -1,d2
121 mov +1,d3
122 setlb # setlb requires the next insns
123 # to occupy exactly 4 bytes
124
125 sub d3,d2
126 movbu (a1),d0
127 movbu d0,(a0)
128 add_add d3,a1,d3,a0
129 lcc
130
131 mov e3,a0
132 ret [d2,d3],8
133
134memcpy_end:
135 .size memcpy, memcpy_end-memcpy