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1da177e4 LT |
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 | */ | |
24 | ENTRY(_find_first_zero_bit_le) | |
25 | teq r1, #0 | |
26 | beq 3f | |
27 | mov r2, #0 | |
8b592783 CM |
28 | 1: |
29 | ARM( ldrb r3, [r0, r2, lsr #3] ) | |
30 | THUMB( lsr r3, r2, #3 ) | |
31 | THUMB( ldrb r3, [r0, r3] ) | |
1da177e4 | 32 | eors r3, r3, #0xff @ invert bits |
8adbb371 | 33 | bne .L_found @ any now set - found zero bit |
1da177e4 LT |
34 | add r2, r2, #8 @ next bit pointer |
35 | 2: cmp r2, r1 @ any more? | |
36 | blo 1b | |
37 | 3: mov r0, r1 @ no free bits | |
7999d8d7 | 38 | mov pc, lr |
93ed3970 | 39 | ENDPROC(_find_first_zero_bit_le) |
1da177e4 LT |
40 | |
41 | /* | |
42 | * Purpose : Find next 'zero' bit | |
43 | * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) | |
44 | */ | |
45 | ENTRY(_find_next_zero_bit_le) | |
46 | teq r1, #0 | |
47 | beq 3b | |
48 | ands ip, r2, #7 | |
49 | beq 1b @ If new byte, goto old routine | |
8b592783 CM |
50 | ARM( ldrb r3, [r0, r2, lsr #3] ) |
51 | THUMB( lsr r3, r2, #3 ) | |
52 | THUMB( ldrb r3, [r0, r3] ) | |
1da177e4 LT |
53 | eor r3, r3, #0xff @ now looking for a 1 bit |
54 | movs r3, r3, lsr ip @ shift off unused bits | |
8adbb371 | 55 | bne .L_found |
1da177e4 LT |
56 | orr r2, r2, #7 @ if zero, then no bits here |
57 | add r2, r2, #1 @ align bit pointer | |
58 | b 2b @ loop for next bit | |
93ed3970 | 59 | ENDPROC(_find_next_zero_bit_le) |
1da177e4 LT |
60 | |
61 | /* | |
62 | * Purpose : Find a 'one' bit | |
63 | * Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit); | |
64 | */ | |
65 | ENTRY(_find_first_bit_le) | |
66 | teq r1, #0 | |
67 | beq 3f | |
68 | mov r2, #0 | |
8b592783 CM |
69 | 1: |
70 | ARM( ldrb r3, [r0, r2, lsr #3] ) | |
71 | THUMB( lsr r3, r2, #3 ) | |
72 | THUMB( ldrb r3, [r0, r3] ) | |
1da177e4 | 73 | movs r3, r3 |
8adbb371 | 74 | bne .L_found @ any now set - found zero bit |
1da177e4 LT |
75 | add r2, r2, #8 @ next bit pointer |
76 | 2: cmp r2, r1 @ any more? | |
77 | blo 1b | |
78 | 3: mov r0, r1 @ no free bits | |
7999d8d7 | 79 | mov pc, lr |
93ed3970 | 80 | ENDPROC(_find_first_bit_le) |
1da177e4 LT |
81 | |
82 | /* | |
83 | * Purpose : Find next 'one' bit | |
84 | * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) | |
85 | */ | |
86 | ENTRY(_find_next_bit_le) | |
87 | teq r1, #0 | |
88 | beq 3b | |
89 | ands ip, r2, #7 | |
90 | beq 1b @ If new byte, goto old routine | |
8b592783 CM |
91 | ARM( ldrb r3, [r0, r2, lsr #3] ) |
92 | THUMB( lsr r3, r2, #3 ) | |
93 | THUMB( ldrb r3, [r0, r3] ) | |
1da177e4 | 94 | movs r3, r3, lsr ip @ shift off unused bits |
8adbb371 | 95 | bne .L_found |
1da177e4 LT |
96 | orr r2, r2, #7 @ if zero, then no bits here |
97 | add r2, r2, #1 @ align bit pointer | |
98 | b 2b @ loop for next bit | |
93ed3970 | 99 | ENDPROC(_find_next_bit_le) |
1da177e4 LT |
100 | |
101 | #ifdef __ARMEB__ | |
102 | ||
103 | ENTRY(_find_first_zero_bit_be) | |
104 | teq r1, #0 | |
105 | beq 3f | |
106 | mov r2, #0 | |
107 | 1: eor r3, r2, #0x18 @ big endian byte ordering | |
8b592783 CM |
108 | ARM( ldrb r3, [r0, r3, lsr #3] ) |
109 | THUMB( lsr r3, #3 ) | |
110 | THUMB( ldrb r3, [r0, r3] ) | |
1da177e4 | 111 | eors r3, r3, #0xff @ invert bits |
8adbb371 | 112 | bne .L_found @ any now set - found zero bit |
1da177e4 LT |
113 | add r2, r2, #8 @ next bit pointer |
114 | 2: cmp r2, r1 @ any more? | |
115 | blo 1b | |
116 | 3: mov r0, r1 @ no free bits | |
7999d8d7 | 117 | mov pc, lr |
93ed3970 | 118 | ENDPROC(_find_first_zero_bit_be) |
1da177e4 LT |
119 | |
120 | ENTRY(_find_next_zero_bit_be) | |
121 | teq r1, #0 | |
122 | beq 3b | |
123 | ands ip, r2, #7 | |
124 | beq 1b @ If new byte, goto old routine | |
125 | eor r3, r2, #0x18 @ big endian byte ordering | |
8b592783 CM |
126 | ARM( ldrb r3, [r0, r3, lsr #3] ) |
127 | THUMB( lsr r3, #3 ) | |
128 | THUMB( ldrb r3, [r0, r3] ) | |
1da177e4 LT |
129 | eor r3, r3, #0xff @ now looking for a 1 bit |
130 | movs r3, r3, lsr ip @ shift off unused bits | |
8adbb371 | 131 | bne .L_found |
1da177e4 LT |
132 | orr r2, r2, #7 @ if zero, then no bits here |
133 | add r2, r2, #1 @ align bit pointer | |
134 | b 2b @ loop for next bit | |
93ed3970 | 135 | ENDPROC(_find_next_zero_bit_be) |
1da177e4 LT |
136 | |
137 | ENTRY(_find_first_bit_be) | |
138 | teq r1, #0 | |
139 | beq 3f | |
140 | mov r2, #0 | |
141 | 1: eor r3, r2, #0x18 @ big endian byte ordering | |
8b592783 CM |
142 | ARM( ldrb r3, [r0, r3, lsr #3] ) |
143 | THUMB( lsr r3, #3 ) | |
144 | THUMB( ldrb r3, [r0, r3] ) | |
1da177e4 | 145 | movs r3, r3 |
8adbb371 | 146 | bne .L_found @ any now set - found zero bit |
1da177e4 LT |
147 | add r2, r2, #8 @ next bit pointer |
148 | 2: cmp r2, r1 @ any more? | |
149 | blo 1b | |
150 | 3: mov r0, r1 @ no free bits | |
7999d8d7 | 151 | mov pc, lr |
93ed3970 | 152 | ENDPROC(_find_first_bit_be) |
1da177e4 LT |
153 | |
154 | ENTRY(_find_next_bit_be) | |
155 | teq r1, #0 | |
156 | beq 3b | |
157 | ands ip, r2, #7 | |
158 | beq 1b @ If new byte, goto old routine | |
159 | eor r3, r2, #0x18 @ big endian byte ordering | |
8b592783 CM |
160 | ARM( ldrb r3, [r0, r3, lsr #3] ) |
161 | THUMB( lsr r3, #3 ) | |
162 | THUMB( ldrb r3, [r0, r3] ) | |
1da177e4 | 163 | movs r3, r3, lsr ip @ shift off unused bits |
8adbb371 | 164 | bne .L_found |
1da177e4 LT |
165 | orr r2, r2, #7 @ if zero, then no bits here |
166 | add r2, r2, #1 @ align bit pointer | |
167 | b 2b @ loop for next bit | |
93ed3970 | 168 | ENDPROC(_find_next_bit_be) |
1da177e4 LT |
169 | |
170 | #endif | |
171 | ||
172 | /* | |
173 | * One or more bits in the LSB of r3 are assumed to be set. | |
174 | */ | |
8adbb371 | 175 | .L_found: |
1da177e4 | 176 | #if __LINUX_ARM_ARCH__ >= 5 |
0e91ec0c JJ |
177 | rsb r0, r3, #0 |
178 | and r3, r3, r0 | |
1da177e4 LT |
179 | clz r3, r3 |
180 | rsb r3, r3, #31 | |
181 | add r0, r2, r3 | |
182 | #else | |
183 | tst r3, #0x0f | |
184 | addeq r2, r2, #4 | |
185 | movne r3, r3, lsl #4 | |
186 | tst r3, #0x30 | |
187 | addeq r2, r2, #2 | |
188 | movne r3, r3, lsl #2 | |
189 | tst r3, #0x40 | |
190 | addeq r2, r2, #1 | |
191 | mov r0, r2 | |
192 | #endif | |
0e91ec0c JJ |
193 | cmp r1, r0 @ Clamp to maxbit |
194 | movlo r0, r1 | |
7999d8d7 | 195 | mov pc, lr |
1da177e4 | 196 |