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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/lib/findbit.S
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/arm/lib/findbit.S')
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1 files changed, 168 insertions, 0 deletions
diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S
new file mode 100644
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1/*
2 * linux/arch/arm/lib/findbit.S
3 *
4 * Copyright (C) 1995-2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * 16th March 2001 - John Ripley <jripley@sonicblue.com>
11 * Fixed so that "size" is an exclusive not an inclusive quantity.
12 * All users of these functions expect exclusive sizes, and may
13 * also call with zero size.
14 * Reworked by rmk.
15 */
16#include <linux/linkage.h>
17#include <asm/assembler.h>
18 .text
19
20/*
21 * Purpose : Find a 'zero' bit
22 * Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
23 */
24ENTRY(_find_first_zero_bit_le)
25 teq r1, #0
26 beq 3f
27 mov r2, #0
281: ldrb r3, [r0, r2, lsr #3]
29 eors r3, r3, #0xff @ invert bits
30 bne .found @ any now set - found zero bit
31 add r2, r2, #8 @ next bit pointer
322: cmp r2, r1 @ any more?
33 blo 1b
343: mov r0, r1 @ no free bits
35 RETINSTR(mov,pc,lr)
36
37/*
38 * Purpose : Find next 'zero' bit
39 * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
40 */
41ENTRY(_find_next_zero_bit_le)
42 teq r1, #0
43 beq 3b
44 ands ip, r2, #7
45 beq 1b @ If new byte, goto old routine
46 ldrb r3, [r0, r2, lsr #3]
47 eor r3, r3, #0xff @ now looking for a 1 bit
48 movs r3, r3, lsr ip @ shift off unused bits
49 bne .found
50 orr r2, r2, #7 @ if zero, then no bits here
51 add r2, r2, #1 @ align bit pointer
52 b 2b @ loop for next bit
53
54/*
55 * Purpose : Find a 'one' bit
56 * Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit);
57 */
58ENTRY(_find_first_bit_le)
59 teq r1, #0
60 beq 3f
61 mov r2, #0
621: ldrb r3, [r0, r2, lsr #3]
63 movs r3, r3
64 bne .found @ any now set - found zero bit
65 add r2, r2, #8 @ next bit pointer
662: cmp r2, r1 @ any more?
67 blo 1b
683: mov r0, r1 @ no free bits
69 RETINSTR(mov,pc,lr)
70
71/*
72 * Purpose : Find next 'one' bit
73 * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
74 */
75ENTRY(_find_next_bit_le)
76 teq r1, #0
77 beq 3b
78 ands ip, r2, #7
79 beq 1b @ If new byte, goto old routine
80 ldrb r3, [r0, r2, lsr #3]
81 movs r3, r3, lsr ip @ shift off unused bits
82 bne .found
83 orr r2, r2, #7 @ if zero, then no bits here
84 add r2, r2, #1 @ align bit pointer
85 b 2b @ loop for next bit
86
87#ifdef __ARMEB__
88
89ENTRY(_find_first_zero_bit_be)
90 teq r1, #0
91 beq 3f
92 mov r2, #0
931: eor r3, r2, #0x18 @ big endian byte ordering
94 ldrb r3, [r0, r3, lsr #3]
95 eors r3, r3, #0xff @ invert bits
96 bne .found @ any now set - found zero bit
97 add r2, r2, #8 @ next bit pointer
982: cmp r2, r1 @ any more?
99 blo 1b
1003: mov r0, r1 @ no free bits
101 RETINSTR(mov,pc,lr)
102
103ENTRY(_find_next_zero_bit_be)
104 teq r1, #0
105 beq 3b
106 ands ip, r2, #7
107 beq 1b @ If new byte, goto old routine
108 eor r3, r2, #0x18 @ big endian byte ordering
109 ldrb r3, [r0, r3, lsr #3]
110 eor r3, r3, #0xff @ now looking for a 1 bit
111 movs r3, r3, lsr ip @ shift off unused bits
112 bne .found
113 orr r2, r2, #7 @ if zero, then no bits here
114 add r2, r2, #1 @ align bit pointer
115 b 2b @ loop for next bit
116
117ENTRY(_find_first_bit_be)
118 teq r1, #0
119 beq 3f
120 mov r2, #0
1211: eor r3, r2, #0x18 @ big endian byte ordering
122 ldrb r3, [r0, r3, lsr #3]
123 movs r3, r3
124 bne .found @ any now set - found zero bit
125 add r2, r2, #8 @ next bit pointer
1262: cmp r2, r1 @ any more?
127 blo 1b
1283: mov r0, r1 @ no free bits
129 RETINSTR(mov,pc,lr)
130
131ENTRY(_find_next_bit_be)
132 teq r1, #0
133 beq 3b
134 ands ip, r2, #7
135 beq 1b @ If new byte, goto old routine
136 eor r3, r2, #0x18 @ big endian byte ordering
137 ldrb r3, [r0, r3, lsr #3]
138 movs r3, r3, lsr ip @ shift off unused bits
139 bne .found
140 orr r2, r2, #7 @ if zero, then no bits here
141 add r2, r2, #1 @ align bit pointer
142 b 2b @ loop for next bit
143
144#endif
145
146/*
147 * One or more bits in the LSB of r3 are assumed to be set.
148 */
149.found:
150#if __LINUX_ARM_ARCH__ >= 5
151 rsb r1, r3, #0
152 and r3, r3, r1
153 clz r3, r3
154 rsb r3, r3, #31
155 add r0, r2, r3
156#else
157 tst r3, #0x0f
158 addeq r2, r2, #4
159 movne r3, r3, lsl #4
160 tst r3, #0x30
161 addeq r2, r2, #2
162 movne r3, r3, lsl #2
163 tst r3, #0x40
164 addeq r2, r2, #1
165 mov r0, r2
166#endif
167 RETINSTR(mov,pc,lr)
168
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