| /* |
| * 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: ldrb r3, [r0, r2, lsr #3] |
| 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 |
| mov pc, lr |
| |
| /* |
| * 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 |
| ldrb r3, [r0, r2, lsr #3] |
| 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 |
| |
| /* |
| * 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: ldrb r3, [r0, r2, lsr #3] |
| 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 |
| mov pc, lr |
| |
| /* |
| * 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 |
| ldrb r3, [r0, r2, lsr #3] |
| 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 |
| |
| #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 |
| ldrb r3, [r0, r3, lsr #3] |
| 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 |
| mov pc, lr |
| |
| 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 |
| ldrb r3, [r0, r3, lsr #3] |
| 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 |
| |
| ENTRY(_find_first_bit_be) |
| teq r1, #0 |
| beq 3f |
| mov r2, #0 |
| 1: eor r3, r2, #0x18 @ big endian byte ordering |
| ldrb r3, [r0, r3, lsr #3] |
| 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 |
| mov pc, lr |
| |
| 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 |
| ldrb r3, [r0, r3, lsr #3] |
| 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 |
| |
| #endif |
| |
| /* |
| * One or more bits in the LSB of r3 are assumed to be set. |
| */ |
| .L_found: |
| #if __LINUX_ARM_ARCH__ >= 5 |
| rsb r1, r3, #0 |
| and r3, r3, r1 |
| 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 |
| mov pc, lr |
| |