Linux-2.6.12-rc2
[linux-3.10.git] / arch / frv / lib / memcpy.S
1 /* memcpy.S: optimised assembly memcpy
2  *
3  * Copyright (C) 2003 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 License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11
12
13         .text
14         .p2align        4
15
16 ###############################################################################
17 #
18 # void *memcpy(void *to, const char *from, size_t count)
19 #
20 # - NOTE: must not use any stack. exception detection performs function return
21 #         to caller's fixup routine, aborting the remainder of the copy
22 #
23 ###############################################################################
24         .globl          memcpy,__memcpy_end
25         .type           memcpy,@function
26 memcpy:
27         or.p            gr8,gr9,gr4
28         orcc            gr10,gr0,gr0,icc3
29         or.p            gr10,gr4,gr4
30         beqlr           icc3,#0
31
32         # optimise based on best common alignment for to, from & count
33         andicc.p        gr4,#0x0f,gr0,icc0
34         setlos          #8,gr11
35         andicc.p        gr4,#0x07,gr0,icc1
36         beq             icc0,#0,memcpy_16
37         andicc.p        gr4,#0x03,gr0,icc0
38         beq             icc1,#0,memcpy_8
39         andicc.p        gr4,#0x01,gr0,icc1
40         beq             icc0,#0,memcpy_4
41         setlos.p        #1,gr11
42         beq             icc1,#0,memcpy_2
43
44         # do byte by byte copy
45         sub.p           gr8,gr11,gr3
46         sub             gr9,gr11,gr9
47 0:      ldubu.p         @(gr9,gr11),gr4
48         subicc          gr10,#1,gr10,icc0
49         stbu.p          gr4,@(gr3,gr11)
50         bne             icc0,#2,0b
51         bralr
52
53         # do halfword by halfword copy
54 memcpy_2:
55         setlos          #2,gr11
56         sub.p           gr8,gr11,gr3
57         sub             gr9,gr11,gr9
58 0:      lduhu.p         @(gr9,gr11),gr4
59         subicc          gr10,#2,gr10,icc0
60         sthu.p          gr4,@(gr3,gr11)
61         bne             icc0,#2,0b
62         bralr
63
64         # do word by word copy
65 memcpy_4:
66         setlos          #4,gr11
67         sub.p           gr8,gr11,gr3
68         sub             gr9,gr11,gr9
69 0:      ldu.p           @(gr9,gr11),gr4
70         subicc          gr10,#4,gr10,icc0
71         stu.p           gr4,@(gr3,gr11)
72         bne             icc0,#2,0b
73         bralr
74
75         # do double-word by double-word copy
76 memcpy_8:
77         sub.p           gr8,gr11,gr3
78         sub             gr9,gr11,gr9
79 0:      lddu.p          @(gr9,gr11),gr4
80         subicc          gr10,#8,gr10,icc0
81         stdu.p          gr4,@(gr3,gr11)
82         bne             icc0,#2,0b
83         bralr
84
85         # do quad-word by quad-word copy
86 memcpy_16:
87         sub.p           gr8,gr11,gr3
88         sub             gr9,gr11,gr9
89 0:      lddu            @(gr9,gr11),gr4
90         lddu.p          @(gr9,gr11),gr6
91         subicc          gr10,#16,gr10,icc0
92         stdu            gr4,@(gr3,gr11)
93         stdu.p          gr6,@(gr3,gr11)
94         bne             icc0,#2,0b
95         bralr
96 __memcpy_end:
97
98         .size           memcpy, __memcpy_end-memcpy
99
100 ###############################################################################
101 #
102 # copy to/from userspace
103 # - return the number of bytes that could not be copied (0 on complete success)
104 #
105 # long __memcpy_user(void *dst, const void *src, size_t count)
106 #
107 ###############################################################################
108         .globl          __memcpy_user, __memcpy_user_error_lr, __memcpy_user_error_handler
109         .type           __memcpy_user,@function
110 __memcpy_user:
111         movsg           lr,gr7
112         subi.p          sp,#8,sp
113         add             gr8,gr10,gr6            ; calculate expected end address
114         stdi            gr6,@(sp,#0)
115
116         # abuse memcpy to do the dirty work
117         call            memcpy
118 __memcpy_user_error_lr:
119         ldi.p           @(sp,#4),gr7
120         setlos          #0,gr8
121         jmpl.p          @(gr7,gr0)
122         addi            sp,#8,sp
123
124         # deal any exception generated by memcpy
125         # GR8 - memcpy's current dest address
126         # GR11 - memset's step value (index register for store insns)
127 __memcpy_user_error_handler:
128         lddi.p          @(sp,#0),gr4            ; load GR4 with dst+count, GR5 with ret addr
129         add             gr11,gr3,gr7
130         sub.p           gr4,gr7,gr8
131
132         addi            sp,#8,sp
133         jmpl            @(gr5,gr0)
134
135         .size           __memcpy_user, .-__memcpy_user