195 строки
4.8 KiB
ArmAsm
195 строки
4.8 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:
|
|
ARM( ldrb r3, [r0, r2, lsr #3] )
|
|
THUMB( lsr r3, r2, #3 )
|
|
THUMB( ldrb r3, [r0, r3] )
|
|
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
|
|
ENDPROC(_find_first_zero_bit_le)
|
|
|
|
/*
|
|
* 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
|
|
ARM( ldrb r3, [r0, r2, lsr #3] )
|
|
THUMB( lsr r3, r2, #3 )
|
|
THUMB( ldrb r3, [r0, r3] )
|
|
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
|
|
ENDPROC(_find_next_zero_bit_le)
|
|
|
|
/*
|
|
* 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:
|
|
ARM( ldrb r3, [r0, r2, lsr #3] )
|
|
THUMB( lsr r3, r2, #3 )
|
|
THUMB( ldrb r3, [r0, r3] )
|
|
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
|
|
ENDPROC(_find_first_bit_le)
|
|
|
|
/*
|
|
* 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
|
|
ARM( ldrb r3, [r0, r2, lsr #3] )
|
|
THUMB( lsr r3, r2, #3 )
|
|
THUMB( ldrb r3, [r0, r3] )
|
|
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
|
|
ENDPROC(_find_next_bit_le)
|
|
|
|
#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
|
|
ARM( ldrb r3, [r0, r3, lsr #3] )
|
|
THUMB( lsr r3, #3 )
|
|
THUMB( ldrb r3, [r0, r3] )
|
|
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
|
|
ENDPROC(_find_first_zero_bit_be)
|
|
|
|
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
|
|
ARM( ldrb r3, [r0, r3, lsr #3] )
|
|
THUMB( lsr r3, #3 )
|
|
THUMB( ldrb r3, [r0, r3] )
|
|
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
|
|
ENDPROC(_find_next_zero_bit_be)
|
|
|
|
ENTRY(_find_first_bit_be)
|
|
teq r1, #0
|
|
beq 3f
|
|
mov r2, #0
|
|
1: eor r3, r2, #0x18 @ big endian byte ordering
|
|
ARM( ldrb r3, [r0, r3, lsr #3] )
|
|
THUMB( lsr r3, #3 )
|
|
THUMB( ldrb r3, [r0, r3] )
|
|
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
|
|
ENDPROC(_find_first_bit_be)
|
|
|
|
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
|
|
ARM( ldrb r3, [r0, r3, lsr #3] )
|
|
THUMB( lsr r3, #3 )
|
|
THUMB( ldrb r3, [r0, r3] )
|
|
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
|
|
ENDPROC(_find_next_bit_be)
|
|
|
|
#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
|
|
|