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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)