Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
| 28 | 1: ldrb r3, [r0, r2, lsr #3] |
| 29 | eors r3, r3, #0xff @ invert bits |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 30 | bne .L_found @ any now set - found zero bit |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | add r2, r2, #8 @ next bit pointer |
| 32 | 2: cmp r2, r1 @ any more? |
| 33 | blo 1b |
| 34 | 3: mov r0, r1 @ no free bits |
Russell King | 7999d8d | 2006-06-25 11:17:23 +0100 | [diff] [blame] | 35 | mov pc, lr |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame^] | 36 | ENDPROC(_find_first_zero_bit_le) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | |
| 38 | /* |
| 39 | * Purpose : Find next 'zero' bit |
| 40 | * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) |
| 41 | */ |
| 42 | ENTRY(_find_next_zero_bit_le) |
| 43 | teq r1, #0 |
| 44 | beq 3b |
| 45 | ands ip, r2, #7 |
| 46 | beq 1b @ If new byte, goto old routine |
| 47 | ldrb r3, [r0, r2, lsr #3] |
| 48 | eor r3, r3, #0xff @ now looking for a 1 bit |
| 49 | movs r3, r3, lsr ip @ shift off unused bits |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 50 | bne .L_found |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | orr r2, r2, #7 @ if zero, then no bits here |
| 52 | add r2, r2, #1 @ align bit pointer |
| 53 | b 2b @ loop for next bit |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame^] | 54 | ENDPROC(_find_next_zero_bit_le) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | |
| 56 | /* |
| 57 | * Purpose : Find a 'one' bit |
| 58 | * Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit); |
| 59 | */ |
| 60 | ENTRY(_find_first_bit_le) |
| 61 | teq r1, #0 |
| 62 | beq 3f |
| 63 | mov r2, #0 |
| 64 | 1: ldrb r3, [r0, r2, lsr #3] |
| 65 | movs r3, r3 |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 66 | bne .L_found @ any now set - found zero bit |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | add r2, r2, #8 @ next bit pointer |
| 68 | 2: cmp r2, r1 @ any more? |
| 69 | blo 1b |
| 70 | 3: mov r0, r1 @ no free bits |
Russell King | 7999d8d | 2006-06-25 11:17:23 +0100 | [diff] [blame] | 71 | mov pc, lr |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame^] | 72 | ENDPROC(_find_first_bit_le) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | |
| 74 | /* |
| 75 | * Purpose : Find next 'one' bit |
| 76 | * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) |
| 77 | */ |
| 78 | ENTRY(_find_next_bit_le) |
| 79 | teq r1, #0 |
| 80 | beq 3b |
| 81 | ands ip, r2, #7 |
| 82 | beq 1b @ If new byte, goto old routine |
| 83 | ldrb r3, [r0, r2, lsr #3] |
| 84 | movs r3, r3, lsr ip @ shift off unused bits |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 85 | bne .L_found |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | orr r2, r2, #7 @ if zero, then no bits here |
| 87 | add r2, r2, #1 @ align bit pointer |
| 88 | b 2b @ loop for next bit |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame^] | 89 | ENDPROC(_find_next_bit_le) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | |
| 91 | #ifdef __ARMEB__ |
| 92 | |
| 93 | ENTRY(_find_first_zero_bit_be) |
| 94 | teq r1, #0 |
| 95 | beq 3f |
| 96 | mov r2, #0 |
| 97 | 1: eor r3, r2, #0x18 @ big endian byte ordering |
| 98 | ldrb r3, [r0, r3, lsr #3] |
| 99 | eors r3, r3, #0xff @ invert bits |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 100 | bne .L_found @ any now set - found zero bit |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | add r2, r2, #8 @ next bit pointer |
| 102 | 2: cmp r2, r1 @ any more? |
| 103 | blo 1b |
| 104 | 3: mov r0, r1 @ no free bits |
Russell King | 7999d8d | 2006-06-25 11:17:23 +0100 | [diff] [blame] | 105 | mov pc, lr |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame^] | 106 | ENDPROC(_find_first_zero_bit_be) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | |
| 108 | ENTRY(_find_next_zero_bit_be) |
| 109 | teq r1, #0 |
| 110 | beq 3b |
| 111 | ands ip, r2, #7 |
| 112 | beq 1b @ If new byte, goto old routine |
| 113 | eor r3, r2, #0x18 @ big endian byte ordering |
| 114 | ldrb r3, [r0, r3, lsr #3] |
| 115 | eor r3, r3, #0xff @ now looking for a 1 bit |
| 116 | movs r3, r3, lsr ip @ shift off unused bits |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 117 | bne .L_found |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | orr r2, r2, #7 @ if zero, then no bits here |
| 119 | add r2, r2, #1 @ align bit pointer |
| 120 | b 2b @ loop for next bit |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame^] | 121 | ENDPROC(_find_next_zero_bit_be) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | |
| 123 | ENTRY(_find_first_bit_be) |
| 124 | teq r1, #0 |
| 125 | beq 3f |
| 126 | mov r2, #0 |
| 127 | 1: eor r3, r2, #0x18 @ big endian byte ordering |
| 128 | ldrb r3, [r0, r3, lsr #3] |
| 129 | movs r3, r3 |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 130 | bne .L_found @ any now set - found zero bit |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | add r2, r2, #8 @ next bit pointer |
| 132 | 2: cmp r2, r1 @ any more? |
| 133 | blo 1b |
| 134 | 3: mov r0, r1 @ no free bits |
Russell King | 7999d8d | 2006-06-25 11:17:23 +0100 | [diff] [blame] | 135 | mov pc, lr |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame^] | 136 | ENDPROC(_find_first_bit_be) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | |
| 138 | ENTRY(_find_next_bit_be) |
| 139 | teq r1, #0 |
| 140 | beq 3b |
| 141 | ands ip, r2, #7 |
| 142 | beq 1b @ If new byte, goto old routine |
| 143 | eor r3, r2, #0x18 @ big endian byte ordering |
| 144 | ldrb r3, [r0, r3, lsr #3] |
| 145 | movs r3, r3, lsr ip @ shift off unused bits |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 146 | bne .L_found |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | orr r2, r2, #7 @ if zero, then no bits here |
| 148 | add r2, r2, #1 @ align bit pointer |
| 149 | b 2b @ loop for next bit |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame^] | 150 | ENDPROC(_find_next_bit_be) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | |
| 152 | #endif |
| 153 | |
| 154 | /* |
| 155 | * One or more bits in the LSB of r3 are assumed to be set. |
| 156 | */ |
Nicolas Pitre | 8adbb37 | 2005-11-11 21:51:49 +0000 | [diff] [blame] | 157 | .L_found: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | #if __LINUX_ARM_ARCH__ >= 5 |
| 159 | rsb r1, r3, #0 |
| 160 | and r3, r3, r1 |
| 161 | clz r3, r3 |
| 162 | rsb r3, r3, #31 |
| 163 | add r0, r2, r3 |
| 164 | #else |
| 165 | tst r3, #0x0f |
| 166 | addeq r2, r2, #4 |
| 167 | movne r3, r3, lsl #4 |
| 168 | tst r3, #0x30 |
| 169 | addeq r2, r2, #2 |
| 170 | movne r3, r3, lsl #2 |
| 171 | tst r3, #0x40 |
| 172 | addeq r2, r2, #1 |
| 173 | mov r0, r2 |
| 174 | #endif |
Russell King | 7999d8d | 2006-06-25 11:17:23 +0100 | [diff] [blame] | 175 | mov pc, lr |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | |