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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2010-11-13 weety first version
*/
//#include <rtthread.h>
//.text
/*
* Purpose : Find a 'zero' bit
* Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
*/
.globl _find_first_zero_bit_le
_find_first_zero_bit_le:
teq r1, #0
beq 3f
mov r2, #0
1:
ldrb r3, [r0, r2, lsr #3]
lsr r3, r2, #3
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)
*/
.globl _find_next_zero_bit_le
_find_next_zero_bit_le:
teq r1, #0
beq 3b
ands ip, r2, #7
beq 1b @ If new byte, goto old routine
ldrb r3, [r0, r2, lsr #3]
lsr r3, r2, #3
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);
*/
.globl _find_first_bit_le
_find_first_bit_le:
teq r1, #0
beq 3f
mov r2, #0
1:
ldrb r3, [r0, r2, lsr #3]
lsr r3, r2, #3
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)
*/
.globl _find_next_bit_le
_find_next_bit_le:
teq r1, #0
beq 3b
ands ip, r2, #7
beq 1b @ If new byte, goto old routine
ldrb r3, [r0, r2, lsr #3]
lsr r3, r2, #3
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 1 //__LINUX_ARM_ARCH__ >= 5
rsb r0, r3, #0
and r3, r3, r0
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
cmp r1, r0 @ Clamp to maxbit
movlo r0, r1
mov pc, lr
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