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/*
* 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.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
.text
/*
* Purpose : Find a 'zero' bit
* Prototype: int find_first_zero_bit(void *addr, int maxbit);
*/
ENTRY(find_first_zero_bit)
mov r2, #0
.bytelp: ldrb r3, [r0, r2, lsr #3]
eors r3, r3, #0xff @ invert bits
bne .found @ any now set - found zero bit
add r2, r2, #8 @ next bit pointer
cmp r2, r1 @ any more?
bcc .bytelp
add r0, r1, #1 @ no free bits
RETINSTR(mov,pc,lr)
/*
* Purpose : Find next 'zero' bit
* Prototype: int find_next_zero_bit(void *addr, int maxbit, int offset)
*/
ENTRY(find_next_zero_bit)
ands ip, r2, #7
beq .bytelp @ 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
orreq r2, r2, #7 @ if zero, then no bits here
addeq r2, r2, #1 @ align bit pointer
beq .bytelp @ loop for next bit
/*
* One or more bits in the LSB of r3 are assumed to be set.
*/
.found: 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
RETINSTR(mov,pc,lr)
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