1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/arch/arm/lib/io-writesw-armv4.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 strh \rd, [r0]
13 mov \rd, \rd, lsr #16
14 strh \rd, [r0]
15#else
16 mov lr, \rd, lsr #16
17 strh lr, [r0]
18 strh \rd, [r0]
19#endif
20 .endm
21
22.Loutsw_align: movs ip, r1, lsl #31
23 bne .Loutsw_noalign
24
25 ldrh r3, [r1], #2
26 sub r2, r2, #1
27 strh r3, [r0]
28
29ENTRY(__raw_writesw)
30 teq r2, #0
31 reteq lr
32 ands r3, r1, #3
33 bne .Loutsw_align
34
35 stmfd sp!, {r4, r5, lr}
36
37 subs r2, r2, #8
38 bmi .Lno_outsw_8
39
40.Loutsw_8_lp: ldmia r1!, {r3, r4, r5, ip}
41 subs r2, r2, #8
42 outword r3
43 outword r4
44 outword r5
45 outword ip
46 bpl .Loutsw_8_lp
47
48.Lno_outsw_8: tst r2, #4
49 beq .Lno_outsw_4
50
51 ldmia r1!, {r3, ip}
52 outword r3
53 outword ip
54
55.Lno_outsw_4: movs r2, r2, lsl #31
56 bcc .Lno_outsw_2
57
58 ldr r3, [r1], #4
59 outword r3
60
61.Lno_outsw_2: ldrhne r3, [r1]
62 strhne r3, [r0]
63
64 ldmfd sp!, {r4, r5, pc}
65
66#ifdef __ARMEB__
67#define pull_hbyte0 lsl #8
68#define push_hbyte1 lsr #24
69#else
70#define pull_hbyte0 lsr #24
71#define push_hbyte1 lsl #8
72#endif
73
74.Loutsw_noalign:
75 ARM( ldr r3, [r1, -r3]! )
76 THUMB( rsb r3, r3, #0 )
77 THUMB( ldr r3, [r1, r3] )
78 THUMB( sub r1, r3 )
79 subcs r2, r2, #1
80 bcs 2f
81 subs r2, r2, #2
82 bmi 3f
83
841: mov ip, r3, lsr #8
85 strh ip, [r0]
862: mov ip, r3, pull_hbyte0
87 ldr r3, [r1, #4]!
88 subs r2, r2, #2
89 orr ip, ip, r3, push_hbyte1
90 strh ip, [r0]
91 bpl 1b
92
93 tst r2, #1
943: movne ip, r3, lsr #8
95 strhne ip, [r0]
96 ret lr
97ENDPROC(__raw_writesw)
98

source code of linux/arch/arm/lib/io-writesw-armv4.S