xref: /openbmc/linux/arch/arm/lib/io-readsb.S (revision 132db935)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 *  linux/arch/arm/lib/io-readsb.S
4 *
5 *  Copyright (C) 1995-2000 Russell King
6 */
7#include <linux/linkage.h>
8#include <asm/assembler.h>
9
10.Linsb_align:	rsb	ip, ip, #4
11		cmp	ip, r2
12		movgt	ip, r2
13		cmp	ip, #2
14		ldrb	r3, [r0]
15		strb	r3, [r1], #1
16		ldrbge	r3, [r0]
17		strbge	r3, [r1], #1
18		ldrbgt	r3, [r0]
19		strbgt	r3, [r1], #1
20		subs	r2, r2, ip
21		bne	.Linsb_aligned
22
23ENTRY(__raw_readsb)
24		teq	r2, #0		@ do we have to check for the zero len?
25		reteq	lr
26		ands	ip, r1, #3
27		bne	.Linsb_align
28
29.Linsb_aligned:	stmfd	sp!, {r4 - r6, lr}
30
31		subs	r2, r2, #16
32		bmi	.Linsb_no_16
33
34.Linsb_16_lp:	ldrb	r3, [r0]
35		ldrb	r4, [r0]
36		ldrb	r5, [r0]
37		mov	r3, r3,     put_byte_0
38		ldrb	r6, [r0]
39		orr	r3, r3, r4, put_byte_1
40		ldrb	r4, [r0]
41		orr	r3, r3, r5, put_byte_2
42		ldrb	r5, [r0]
43		orr	r3, r3, r6, put_byte_3
44		ldrb	r6, [r0]
45		mov	r4, r4,     put_byte_0
46		ldrb	ip, [r0]
47		orr	r4, r4, r5, put_byte_1
48		ldrb	r5, [r0]
49		orr	r4, r4, r6, put_byte_2
50		ldrb	r6, [r0]
51		orr	r4, r4, ip, put_byte_3
52		ldrb	ip, [r0]
53		mov	r5, r5,     put_byte_0
54		ldrb	lr, [r0]
55		orr	r5, r5, r6, put_byte_1
56		ldrb	r6, [r0]
57		orr	r5, r5, ip, put_byte_2
58		ldrb	ip, [r0]
59		orr	r5, r5, lr, put_byte_3
60		ldrb	lr, [r0]
61		mov	r6, r6,     put_byte_0
62		orr	r6, r6, ip, put_byte_1
63		ldrb	ip, [r0]
64		orr	r6, r6, lr, put_byte_2
65		orr	r6, r6, ip, put_byte_3
66		stmia	r1!, {r3 - r6}
67
68		subs	r2, r2, #16
69		bpl	.Linsb_16_lp
70
71		tst	r2, #15
72		ldmfdeq	sp!, {r4 - r6, pc}
73
74.Linsb_no_16:	tst	r2, #8
75		beq	.Linsb_no_8
76
77		ldrb	r3, [r0]
78		ldrb	r4, [r0]
79		ldrb	r5, [r0]
80		mov	r3, r3,     put_byte_0
81		ldrb	r6, [r0]
82		orr	r3, r3, r4, put_byte_1
83		ldrb	r4, [r0]
84		orr	r3, r3, r5, put_byte_2
85		ldrb	r5, [r0]
86		orr	r3, r3, r6, put_byte_3
87		ldrb	r6, [r0]
88		mov	r4, r4,     put_byte_0
89		ldrb	ip, [r0]
90		orr	r4, r4, r5, put_byte_1
91		orr	r4, r4, r6, put_byte_2
92		orr	r4, r4, ip, put_byte_3
93		stmia	r1!, {r3, r4}
94
95.Linsb_no_8:	tst	r2, #4
96		beq	.Linsb_no_4
97
98		ldrb	r3, [r0]
99		ldrb	r4, [r0]
100		ldrb	r5, [r0]
101		ldrb	r6, [r0]
102		mov	r3, r3,     put_byte_0
103		orr	r3, r3, r4, put_byte_1
104		orr	r3, r3, r5, put_byte_2
105		orr	r3, r3, r6, put_byte_3
106		str	r3, [r1], #4
107
108.Linsb_no_4:	ands	r2, r2, #3
109		ldmfdeq	sp!, {r4 - r6, pc}
110
111		cmp	r2, #2
112		ldrb	r3, [r0]
113		strb	r3, [r1], #1
114		ldrbge	r3, [r0]
115		strbge	r3, [r1], #1
116		ldrbgt	r3, [r0]
117		strbgt	r3, [r1]
118
119		ldmfd	sp!, {r4 - r6, pc}
120ENDPROC(__raw_readsb)
121