summaryrefslogtreecommitdiff
path: root/arch/arc/lib/strchr-700.S
blob: 55fcc9fb00edfae1dc2b0b0e746559cd128c09a8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
/*
 * Copyright (C) 2004, 2007-2010, 2011-2014 Synopsys, Inc. All rights reserved.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

/*
 * ARC700 has a relatively long pipeline and branch prediction, so we want
 * to avoid branches that are hard to predict.  On the other hand, the
 * presence of the norm instruction makes it easier to operate on whole
 * words branch-free.
 */

.global strchr
.align 4
strchr:
	extb_s	%r1, %r1
	asl	%r5, %r1, 8
	bmsk	%r2, %r0, 1
	or	%r5, %r5, %r1
	mov_s	%r3, 0x01010101
	breq.d	%r2, %r0, .Laligned
	asl	%r4, %r5, 16
	sub_s	%r0, %r0, %r2
	asl	%r7, %r2, 3
	ld_s	%r2, [%r0]
#ifdef __LITTLE_ENDIAN__
	asl	%r7, %r3, %r7
#else /* __BIG_ENDIAN__ */
	lsr	%r7, %r3, %r7
#endif /* _ENDIAN__ */
	or	%r5, %r5, %r4
	ror	%r4, %r3
	sub	%r12, %r2, %r7
	bic_s	%r12, %r12, %r2
	and	%r12, %r12, %r4
	brne.d	%r12, 0, .Lfound0_ua
	xor	%r6, %r2, %r5
	ld.a	%r2, [%r0, 4]
	sub	%r12, %r6, %r7
	bic	%r12, %r12, %r6
#ifdef __LITTLE_ENDIAN__
	and	%r7, %r12, %r4
	/* For speed, we want this branch to be unaligned. */
	breq	%r7, 0, .Loop
	/* Likewise this one */
	b	.Lfound_char
#else /* __BIG_ENDIAN__ */
	and	%r12, %r12, %r4
	/* For speed, we want this branch to be unaligned. */
	breq	%r12, 0, .Loop
	lsr_s	%r12, %r12, 7
	bic 	%r2, %r7, %r6
	b.d	.Lfound_char_b
	and_s	%r2, %r2, %r12
#endif /* _ENDIAN__ */
	/* We require this code address to be unaligned for speed...  */
.Laligned:
	ld_s	%r2, [%r0]
	or	%r5, %r5, %r4
	ror	%r4, %r3
	/* ... so that this code address is aligned, for itself and ...  */
.Loop:
	sub	%r12, %r2, %r3
	bic_s	%r12, %r12, %r2
	and	%r12, %r12, %r4
	brne.d	%r12, 0, .Lfound0
	xor	%r6, %r2, %r5
	ld.a	%r2, [%r0, 4]
	sub	%r12, %r6, %r3
	bic	%r12, %r12, %r6
	and	%r7, %r12, %r4
	breq	%r7, 0, .Loop
	/*
	 *... so that this branch is unaligned.
	 * Found searched-for character.
	 * r0 has already advanced to next word.
	 */
#ifdef __LITTLE_ENDIAN__
	/*
	 * We only need the information about the first matching byte
	 * (i.e. the least significant matching byte) to be exact,
	 * hence there is no problem with carry effects.
	 */
.Lfound_char:
	sub	%r3, %r7, 1
	bic	%r3, %r3, %r7
	norm	%r2, %r3
	sub_s	%r0, %r0, 1
	asr_s	%r2, %r2, 3
	j.d	[%blink]
	sub_s	%r0, %r0, %r2

	.balign	4
.Lfound0_ua:
	mov	%r3, %r7
.Lfound0:
	sub	%r3, %r6, %r3
	bic	%r3, %r3, %r6
	and	%r2, %r3, %r4
	or_s	%r12, %r12, %r2
	sub_s	%r3, %r12, 1
	bic_s	%r3, %r3, %r12
	norm	%r3, %r3
	add_s	%r0, %r0, 3
	asr_s	%r12, %r3, 3
	asl.f	0, %r2, %r3
	sub_s	%r0, %r0, %r12
	j_s.d	[%blink]
	mov.pl	%r0, 0
#else /* __BIG_ENDIAN__ */
.Lfound_char:
	lsr	%r7, %r7, 7

	bic	%r2, %r7, %r6
.Lfound_char_b:
	norm	%r2, %r2
	sub_s	%r0, %r0, 4
	asr_s	%r2, %r2, 3
	j.d	[%blink]
	add_s	%r0, %r0, %r2

.Lfound0_ua:
	mov_s	%r3, %r7
.Lfound0:
	asl_s	%r2, %r2, 7
	or	%r7, %r6, %r4
	bic_s	%r12, %r12, %r2
	sub	%r2, %r7, %r3
	or	%r2, %r2, %r6
	bic	%r12, %r2, %r12
	bic.f	%r3, %r4, %r12
	norm	%r3, %r3

	add.pl	%r3, %r3, 1
	asr_s	%r12, %r3, 3
	asl.f	0, %r2, %r3
	add_s	%r0, %r0, %r12
	j_s.d	[%blink]
	mov.mi	%r0, 0
#endif /* _ENDIAN__ */