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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | /* * linux/arch/arm/lib/findbit.S * * Copyright (C) 1995-2000 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * 16th March 2001 - John Ripley <jripley@sonicblue.com> * Fixed so that "size" is an exclusive not an inclusive quantity. * All users of these functions expect exclusive sizes, and may * also call with zero size. * Reworked by rmk. */ #include <linux/linkage.h> #include <asm/assembler.h> .text /* * Purpose : Find a 'zero' bit * Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit); */ ENTRY(_find_first_zero_bit_le) teq r1, #0 beq 3f mov r2, #0 1: ARM( ldrb r3, [r0, r2, lsr #3] ) THUMB( lsr r3, r2, #3 ) THUMB( ldrb r3, [r0, r3] ) eors r3, r3, #0xff @ invert bits bne .L_found @ any now set - found zero bit add r2, r2, #8 @ next bit pointer 2: cmp r2, r1 @ any more? blo 1b 3: mov r0, r1 @ no free bits ret lr ENDPROC(_find_first_zero_bit_le) /* * Purpose : Find next 'zero' bit * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) */ ENTRY(_find_next_zero_bit_le) teq r1, #0 beq 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine ARM( ldrb r3, [r0, r2, lsr #3] ) THUMB( lsr r3, r2, #3 ) THUMB( ldrb r3, [r0, r3] ) eor r3, r3, #0xff @ now looking for a 1 bit movs r3, r3, lsr ip @ shift off unused bits bne .L_found orr r2, r2, #7 @ if zero, then no bits here add r2, r2, #1 @ align bit pointer b 2b @ loop for next bit ENDPROC(_find_next_zero_bit_le) /* * Purpose : Find a 'one' bit * Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit); */ ENTRY(_find_first_bit_le) teq r1, #0 beq 3f mov r2, #0 1: ARM( ldrb r3, [r0, r2, lsr #3] ) THUMB( lsr r3, r2, #3 ) THUMB( ldrb r3, [r0, r3] ) movs r3, r3 bne .L_found @ any now set - found zero bit add r2, r2, #8 @ next bit pointer 2: cmp r2, r1 @ any more? blo 1b 3: mov r0, r1 @ no free bits ret lr ENDPROC(_find_first_bit_le) /* * Purpose : Find next 'one' bit * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) */ ENTRY(_find_next_bit_le) teq r1, #0 beq 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine ARM( ldrb r3, [r0, r2, lsr #3] ) THUMB( lsr r3, r2, #3 ) THUMB( ldrb r3, [r0, r3] ) movs r3, r3, lsr ip @ shift off unused bits bne .L_found orr r2, r2, #7 @ if zero, then no bits here add r2, r2, #1 @ align bit pointer b 2b @ loop for next bit ENDPROC(_find_next_bit_le) #ifdef __ARMEB__ ENTRY(_find_first_zero_bit_be) teq r1, #0 beq 3f mov r2, #0 1: eor r3, r2, #0x18 @ big endian byte ordering ARM( ldrb r3, [r0, r3, lsr #3] ) THUMB( lsr r3, #3 ) THUMB( ldrb r3, [r0, r3] ) eors r3, r3, #0xff @ invert bits bne .L_found @ any now set - found zero bit add r2, r2, #8 @ next bit pointer 2: cmp r2, r1 @ any more? blo 1b 3: mov r0, r1 @ no free bits ret lr ENDPROC(_find_first_zero_bit_be) ENTRY(_find_next_zero_bit_be) teq r1, #0 beq 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine eor r3, r2, #0x18 @ big endian byte ordering ARM( ldrb r3, [r0, r3, lsr #3] ) THUMB( lsr r3, #3 ) THUMB( ldrb r3, [r0, r3] ) eor r3, r3, #0xff @ now looking for a 1 bit movs r3, r3, lsr ip @ shift off unused bits bne .L_found orr r2, r2, #7 @ if zero, then no bits here add r2, r2, #1 @ align bit pointer b 2b @ loop for next bit ENDPROC(_find_next_zero_bit_be) ENTRY(_find_first_bit_be) teq r1, #0 beq 3f mov r2, #0 1: eor r3, r2, #0x18 @ big endian byte ordering ARM( ldrb r3, [r0, r3, lsr #3] ) THUMB( lsr r3, #3 ) THUMB( ldrb r3, [r0, r3] ) movs r3, r3 bne .L_found @ any now set - found zero bit add r2, r2, #8 @ next bit pointer 2: cmp r2, r1 @ any more? blo 1b 3: mov r0, r1 @ no free bits ret lr ENDPROC(_find_first_bit_be) ENTRY(_find_next_bit_be) teq r1, #0 beq 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine eor r3, r2, #0x18 @ big endian byte ordering ARM( ldrb r3, [r0, r3, lsr #3] ) THUMB( lsr r3, #3 ) THUMB( ldrb r3, [r0, r3] ) movs r3, r3, lsr ip @ shift off unused bits bne .L_found orr r2, r2, #7 @ if zero, then no bits here add r2, r2, #1 @ align bit pointer b 2b @ loop for next bit ENDPROC(_find_next_bit_be) #endif /* * One or more bits in the LSB of r3 are assumed to be set. */ .L_found: #if __LINUX_ARM_ARCH__ >= 5 rsb r0, r3, #0 and r3, r3, r0 clz r3, r3 rsb r3, r3, #31 add r0, r2, r3 #else tst r3, #0x0f addeq r2, r2, #4 movne r3, r3, lsl #4 tst r3, #0x30 addeq r2, r2, #2 movne r3, r3, lsl #2 tst r3, #0x40 addeq r2, r2, #1 mov r0, r2 #endif cmp r1, r0 @ Clamp to maxbit movlo r0, r1 ret lr |