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193 lines
4.7 KiB
193 lines
4.7 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* linux/arch/arm/lib/findbit.S |
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* |
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* Copyright (C) 1995-2000 Russell King |
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* |
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* 16th March 2001 - John Ripley <jripley@sonicblue.com> |
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* Fixed so that "size" is an exclusive not an inclusive quantity. |
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* All users of these functions expect exclusive sizes, and may |
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* also call with zero size. |
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* Reworked by rmk. |
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*/ |
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#include <linux/linkage.h> |
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#include <asm/assembler.h> |
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.text |
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/* |
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* Purpose : Find a 'zero' bit |
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* Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit); |
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*/ |
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ENTRY(_find_first_zero_bit_le) |
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teq r1, #0 |
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beq 3f |
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mov r2, #0 |
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1: |
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ARM( ldrb r3, [r0, r2, lsr #3] ) |
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THUMB( lsr r3, r2, #3 ) |
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THUMB( ldrb r3, [r0, r3] ) |
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eors r3, r3, #0xff @ invert bits |
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bne .L_found @ any now set - found zero bit |
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add r2, r2, #8 @ next bit pointer |
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2: cmp r2, r1 @ any more? |
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blo 1b |
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3: mov r0, r1 @ no free bits |
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ret lr |
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ENDPROC(_find_first_zero_bit_le) |
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/* |
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* Purpose : Find next 'zero' bit |
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* Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) |
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*/ |
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ENTRY(_find_next_zero_bit_le) |
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teq r1, #0 |
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beq 3b |
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ands ip, r2, #7 |
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beq 1b @ If new byte, goto old routine |
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ARM( ldrb r3, [r0, r2, lsr #3] ) |
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THUMB( lsr r3, r2, #3 ) |
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THUMB( ldrb r3, [r0, r3] ) |
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eor r3, r3, #0xff @ now looking for a 1 bit |
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movs r3, r3, lsr ip @ shift off unused bits |
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bne .L_found |
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orr r2, r2, #7 @ if zero, then no bits here |
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add r2, r2, #1 @ align bit pointer |
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b 2b @ loop for next bit |
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ENDPROC(_find_next_zero_bit_le) |
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/* |
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* Purpose : Find a 'one' bit |
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* Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit); |
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*/ |
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ENTRY(_find_first_bit_le) |
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teq r1, #0 |
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beq 3f |
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mov r2, #0 |
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1: |
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ARM( ldrb r3, [r0, r2, lsr #3] ) |
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THUMB( lsr r3, r2, #3 ) |
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THUMB( ldrb r3, [r0, r3] ) |
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movs r3, r3 |
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bne .L_found @ any now set - found zero bit |
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add r2, r2, #8 @ next bit pointer |
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2: cmp r2, r1 @ any more? |
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blo 1b |
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3: mov r0, r1 @ no free bits |
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ret lr |
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ENDPROC(_find_first_bit_le) |
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/* |
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* Purpose : Find next 'one' bit |
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* Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) |
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*/ |
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ENTRY(_find_next_bit_le) |
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teq r1, #0 |
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beq 3b |
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ands ip, r2, #7 |
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beq 1b @ If new byte, goto old routine |
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ARM( ldrb r3, [r0, r2, lsr #3] ) |
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THUMB( lsr r3, r2, #3 ) |
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THUMB( ldrb r3, [r0, r3] ) |
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movs r3, r3, lsr ip @ shift off unused bits |
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bne .L_found |
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orr r2, r2, #7 @ if zero, then no bits here |
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add r2, r2, #1 @ align bit pointer |
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b 2b @ loop for next bit |
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ENDPROC(_find_next_bit_le) |
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#ifdef __ARMEB__ |
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ENTRY(_find_first_zero_bit_be) |
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teq r1, #0 |
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beq 3f |
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mov r2, #0 |
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1: eor r3, r2, #0x18 @ big endian byte ordering |
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ARM( ldrb r3, [r0, r3, lsr #3] ) |
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THUMB( lsr r3, #3 ) |
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THUMB( ldrb r3, [r0, r3] ) |
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eors r3, r3, #0xff @ invert bits |
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bne .L_found @ any now set - found zero bit |
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add r2, r2, #8 @ next bit pointer |
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2: cmp r2, r1 @ any more? |
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blo 1b |
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3: mov r0, r1 @ no free bits |
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ret lr |
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ENDPROC(_find_first_zero_bit_be) |
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ENTRY(_find_next_zero_bit_be) |
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teq r1, #0 |
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beq 3b |
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ands ip, r2, #7 |
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beq 1b @ If new byte, goto old routine |
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eor r3, r2, #0x18 @ big endian byte ordering |
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ARM( ldrb r3, [r0, r3, lsr #3] ) |
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THUMB( lsr r3, #3 ) |
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THUMB( ldrb r3, [r0, r3] ) |
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eor r3, r3, #0xff @ now looking for a 1 bit |
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movs r3, r3, lsr ip @ shift off unused bits |
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bne .L_found |
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orr r2, r2, #7 @ if zero, then no bits here |
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add r2, r2, #1 @ align bit pointer |
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b 2b @ loop for next bit |
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ENDPROC(_find_next_zero_bit_be) |
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ENTRY(_find_first_bit_be) |
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teq r1, #0 |
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beq 3f |
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mov r2, #0 |
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1: eor r3, r2, #0x18 @ big endian byte ordering |
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ARM( ldrb r3, [r0, r3, lsr #3] ) |
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THUMB( lsr r3, #3 ) |
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THUMB( ldrb r3, [r0, r3] ) |
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movs r3, r3 |
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bne .L_found @ any now set - found zero bit |
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add r2, r2, #8 @ next bit pointer |
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2: cmp r2, r1 @ any more? |
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blo 1b |
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3: mov r0, r1 @ no free bits |
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ret lr |
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ENDPROC(_find_first_bit_be) |
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ENTRY(_find_next_bit_be) |
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teq r1, #0 |
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beq 3b |
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ands ip, r2, #7 |
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beq 1b @ If new byte, goto old routine |
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eor r3, r2, #0x18 @ big endian byte ordering |
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ARM( ldrb r3, [r0, r3, lsr #3] ) |
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THUMB( lsr r3, #3 ) |
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THUMB( ldrb r3, [r0, r3] ) |
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movs r3, r3, lsr ip @ shift off unused bits |
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bne .L_found |
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orr r2, r2, #7 @ if zero, then no bits here |
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add r2, r2, #1 @ align bit pointer |
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b 2b @ loop for next bit |
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ENDPROC(_find_next_bit_be) |
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#endif |
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/* |
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* One or more bits in the LSB of r3 are assumed to be set. |
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*/ |
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.L_found: |
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#if __LINUX_ARM_ARCH__ >= 5 |
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rsb r0, r3, #0 |
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and r3, r3, r0 |
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clz r3, r3 |
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rsb r3, r3, #31 |
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add r0, r2, r3 |
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#else |
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tst r3, #0x0f |
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addeq r2, r2, #4 |
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movne r3, r3, lsl #4 |
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tst r3, #0x30 |
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addeq r2, r2, #2 |
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movne r3, r3, lsl #2 |
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tst r3, #0x40 |
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addeq r2, r2, #1 |
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mov r0, r2 |
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#endif |
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cmp r1, r0 @ Clamp to maxbit |
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movlo r0, r1 |
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ret lr |
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