1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * linux/arch/arm/lib/io-writesb.S
4 *
5 * Copyright (C) 1995-2000 Russell King
6 */
7 #include <linux/linkage.h>
8 #include <asm/assembler.h>
9
10 .macro outword, rd
11 #ifndef __ARMEB__
12 strb \rd, [r0]
13 mov \rd, \rd, lsr #8
14 strb \rd, [r0]
15 mov \rd, \rd, lsr #8
16 strb \rd, [r0]
17 mov \rd, \rd, lsr #8
18 strb \rd, [r0]
19 #else
20 mov lr, \rd, lsr #24
21 strb lr, [r0]
22 mov lr, \rd, lsr #16
23 strb lr, [r0]
24 mov lr, \rd, lsr #8
25 strb lr, [r0]
26 strb \rd, [r0]
27 #endif
28 .endm
29
30 .Loutsb_align: rsb ip, ip, #4
31 cmp ip, r2
32 movgt ip, r2
33 cmp ip, #2
34 ldrb r3, [r1], #1
35 strb r3, [r0]
36 ldrbge r3, [r1], #1
37 strbge r3, [r0]
38 ldrbgt r3, [r1], #1
39 strbgt r3, [r0]
40 subs r2, r2, ip
41 bne .Loutsb_aligned
42
43 ENTRY(__raw_writesb)
44 teq r2, #0 @ do we have to check for the zero len?
45 reteq lr
46 ands ip, r1, #3
47 bne .Loutsb_align
48
49 .Loutsb_aligned:
50 stmfd sp!, {r4, r5, lr}
51
52 subs r2, r2, #16
53 bmi .Loutsb_no_16
54
55 .Loutsb_16_lp: ldmia r1!, {r3, r4, r5, ip}
56 outword r3
57 outword r4
58 outword r5
59 outword ip
60 subs r2, r2, #16
61 bpl .Loutsb_16_lp
62
63 tst r2, #15
64 ldmfdeq sp!, {r4, r5, pc}
65
66 .Loutsb_no_16: tst r2, #8
67 beq .Loutsb_no_8
68
69 ldmia r1!, {r3, r4}
70 outword r3
71 outword r4
72
73 .Loutsb_no_8: tst r2, #4
74 beq .Loutsb_no_4
75
76 ldr r3, [r1], #4
77 outword r3
78
79 .Loutsb_no_4: ands r2, r2, #3
80 ldmfdeq sp!, {r4, r5, pc}
81
82 cmp r2, #2
83 ldrb r3, [r1], #1
84 strb r3, [r0]
85 ldrbge r3, [r1], #1
86 strbge r3, [r0]
87 ldrbgt r3, [r1]
88 strbgt r3, [r0]
89
90 ldmfd sp!, {r4, r5, pc}
91 ENDPROC(__raw_writesb)
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