/*
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* linux/arch/unicore32/lib/findbit.S
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*
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* Code specific to PKUnity SoC and UniCore ISA
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*
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* Copyright (C) 2001-2010 GUAN Xue-tao
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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.text
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/*
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* Purpose : Find a 'zero' bit
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* Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
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*/
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ENTRY(find_first_zero_bit)
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cxor.a r1, #0
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beq 3f
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mov r2, #0
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1: ldb r3, [r0+], r2 >> #3
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xor.a r3, r3, #0xff @ invert bits
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bne .L_found @ any now set - found zero bit
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add r2, r2, #8 @ next bit pointer
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2: csub.a r2, r1 @ any more?
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bub 1b
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3: mov r0, r1 @ no free bits
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mov pc, lr
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ENDPROC(find_first_zero_bit)
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/*
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* Purpose : Find next 'zero' bit
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* Prototype: int find_next_zero_bit
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* (void *addr, unsigned int maxbit, int offset)
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*/
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ENTRY(find_next_zero_bit)
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cxor.a r1, #0
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beq 3b
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and.a ip, r2, #7
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beq 1b @ If new byte, goto old routine
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ldb r3, [r0+], r2 >> #3
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xor r3, r3, #0xff @ now looking for a 1 bit
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mov.a r3, r3 >> ip @ shift off unused bits
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bne .L_found
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or r2, r2, #7 @ if zero, then no bits here
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add r2, r2, #1 @ align bit pointer
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b 2b @ loop for next bit
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ENDPROC(find_next_zero_bit)
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/*
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* Purpose : Find a 'one' bit
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* Prototype: int find_first_bit
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* (const unsigned long *addr, unsigned int maxbit);
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*/
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ENTRY(find_first_bit)
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cxor.a r1, #0
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beq 3f
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mov r2, #0
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1: ldb r3, [r0+], r2 >> #3
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mov.a r3, r3
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bne .L_found @ any now set - found zero bit
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add r2, r2, #8 @ next bit pointer
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2: csub.a r2, r1 @ any more?
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bub 1b
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3: mov r0, r1 @ no free bits
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mov pc, lr
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ENDPROC(find_first_bit)
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/*
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* Purpose : Find next 'one' bit
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* Prototype: int find_next_zero_bit
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* (void *addr, unsigned int maxbit, int offset)
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*/
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ENTRY(find_next_bit)
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cxor.a r1, #0
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beq 3b
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and.a ip, r2, #7
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beq 1b @ If new byte, goto old routine
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ldb r3, [r0+], r2 >> #3
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mov.a r3, r3 >> ip @ shift off unused bits
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bne .L_found
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or r2, r2, #7 @ if zero, then no bits here
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add r2, r2, #1 @ align bit pointer
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b 2b @ loop for next bit
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ENDPROC(find_next_bit)
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/*
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* One or more bits in the LSB of r3 are assumed to be set.
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*/
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.L_found:
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rsub r1, r3, #0
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and r3, r3, r1
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cntlz r3, r3
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rsub r3, r3, #31
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add r0, r2, r3
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mov pc, lr
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