mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-27 14:43:58 +08:00
68 lines
1.7 KiB
ArmAsm
68 lines
1.7 KiB
ArmAsm
|
/*
|
||
|
|
* 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 .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
|
||
|
|
RETINSTR(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 2b
|
||
|
|
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 .found
|
||
|
|
orr r2, r2, #7 @ if zero, then no bits here
|
||
|
|
add r2, r2, #1 @ align bit pointer
|
||
|
|
b 2b @ 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)
|
||
|
|
|