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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 

#include 

                .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)