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/*
* linux/arch/unicore32/lib/findbit.S
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Copyright (C) 2001-2010 GUAN Xue-tao
*
* 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, unsigned int maxbit);
*/
__uc32_find_first_zero_bit:
cxor.a r1, #0
beq 3f
mov r2, #0
1: ldb r3, [r0+], r2 >> #3
xor.a r3, r3, #0xff @ invert bits
bne .L_found @ any now set - found zero bit
add r2, r2, #8 @ next bit pointer
2: csub.a r2, r1 @ any more?
bub 1b
3: mov r0, r1 @ no free bits
mov pc, lr
/*
* Purpose : Find next 'zero' bit
* Prototype: int find_next_zero_bit
* (void *addr, unsigned int maxbit, int offset)
*/
ENTRY(__uc32_find_next_zero_bit)
cxor.a r1, #0
beq 3b
and.a ip, r2, #7
beq 1b @ If new byte, goto old routine
ldb r3, [r0+], r2 >> #3
xor r3, r3, #0xff @ now looking for a 1 bit
mov.a r3, r3 >> ip @ shift off unused bits
bne .L_found
or r2, r2, #7 @ if zero, then no bits here
add r2, r2, #1 @ align bit pointer
b 2b @ loop for next bit
ENDPROC(__uc32_find_next_zero_bit)
/*
* Purpose : Find a 'one' bit
* Prototype: int find_first_bit
* (const unsigned long *addr, unsigned int maxbit);
*/
__uc32_find_first_bit:
cxor.a r1, #0
beq 3f
mov r2, #0
1: ldb r3, [r0+], r2 >> #3
mov.a r3, r3
bne .L_found @ any now set - found zero bit
add r2, r2, #8 @ next bit pointer
2: csub.a r2, r1 @ any more?
bub 1b
3: mov r0, r1 @ no free bits
mov pc, lr
/*
* Purpose : Find next 'one' bit
* Prototype: int find_next_zero_bit
* (void *addr, unsigned int maxbit, int offset)
*/
ENTRY(__uc32_find_next_bit)
cxor.a r1, #0
beq 3b
and.a ip, r2, #7
beq 1b @ If new byte, goto old routine
ldb r3, [r0+], r2 >> #3
mov.a r3, r3 >> ip @ shift off unused bits
bne .L_found
or r2, r2, #7 @ if zero, then no bits here
add r2, r2, #1 @ align bit pointer
b 2b @ loop for next bit
ENDPROC(__uc32_find_next_bit)
/*
* One or more bits in the LSB of r3 are assumed to be set.
*/
.L_found:
rsub r1, r3, #0
and r3, r3, r1
cntlz r3, r3
rsub r3, r3, #31
add r0, r2, r3
mov pc, lr
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