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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [armnommu/] [lib/] [bitops.S] - Blame information for rev 1765

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Line No. Rev Author Line
1 1622 jcastillo 
/*
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 * linux/arch/arm/lib/bitops.S
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 *
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 * Copyright (C) 1995, 1996 Russell King
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 */
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#include
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                .text
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@ Purpose  : Function to set a bit
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@ Prototype: int set_bit(int bit,int *addr)
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                .globl  _set_bit,set_bit
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set_bit:
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_set_bit:       add     r1, r1, r0, lsr #3      @ Get byte offset
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                and     r3, r0, #7              @ Get bit offset
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                mov     r0, #1
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                SAVEIRQS(ip)
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                DISABLEIRQS(ip)
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                ldrb    r2, [r1]
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                tst     r2, r0, lsl r3
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                orr     r2, r2, r0, lsl r3
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                moveq   r0, #0
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                strb    r2, [r1]
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                RESTOREIRQS(ip)
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                RETINSTR(mov,pc,lr)
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@ Purpose  : Function to clear a bit
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@ Prototype: int clear_bit(int bit,int *addr)
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                .globl  _clear_bit,clear_bit
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clear_bit:
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_clear_bit:     add     r1, r1, r0, lsr #3      @ Get byte offset
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                and     r3, r0, #7      @ Get bit offset
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                mov     r0, #1
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                SAVEIRQS(ip)
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                DISABLEIRQS(ip)
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                ldrb    r2, [r1]
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                tst     r2, r0, lsl r3
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                bic     r2, r2, r0, lsl r3
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                moveq   r0, #0
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                strb    r2, [r1]
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                RESTOREIRQS(ip)
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                RETINSTR(mov,pc,lr)
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/* Purpose  : Function to change a bit
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 * Prototype: int change_bit(int bit,int *addr)
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 */
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                .globl  _change_bit,change_bit
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change_bit:
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_change_bit:    add     r1, r1, r0, lsr #3
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                and     r3, r0, #7
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                mov     r0, #1
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                SAVEIRQS(ip)
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                DISABLEIRQS(ip)
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                ldrb    r2, [r1]
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                tst     r2, r0, lsl r3
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                eor     r2, r2, r0, lsl r3
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                moveq   r0, #0
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                strb    r2, [r1]
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                RESTOREIRQS(ip)
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                RETINSTR(mov,pc,lr)
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@ Purpose  : Find a 'zero' bit
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@ Prototype: int find_first_zero_bit(char *addr,int maxbit);
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                .globl  _find_first_zero_bit,find_first_zero_bit
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find_first_zero_bit:
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_find_first_zero_bit:
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                mov     r2, #0                  @ Initialise bit position
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Lfindzbit1lp:   ldrb    r3, [r0, r2, lsr #3]    @ Check byte, if 0xFF, then all bits set
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                teq     r3, #0xFF
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                bne     Lfoundzbit
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                add     r2, r2, #8
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                cmp     r2, r1                  @ Check to see if we have come to the end
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                bcc     Lfindzbit1lp
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                add     r0, r1, #1              @ Make sure that we flag an error
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                RETINSTR(mov,pc,lr)
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Lfoundzbit:     tst     r3, #1                  @ Check individual bits
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                moveq   r0, r2
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                RETINSTR(moveq,pc,lr)
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                tst     r3, #2
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                addeq   r0, r2, #1
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                RETINSTR(moveq,pc,lr)
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                tst     r3, #4
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                addeq   r0, r2, #2
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                RETINSTR(moveq,pc,lr)
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                tst     r3, #8
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                addeq   r0, r2, #3
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                RETINSTR(moveq,pc,lr)
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                tst     r3, #16
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                addeq   r0, r2, #4
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                RETINSTR(moveq,pc,lr)
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                tst     r3, #32
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                addeq   r0, r2, #5
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                RETINSTR(moveq,pc,lr)
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                tst     r3, #64
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                addeq   r0, r2, #6
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                RETINSTR(moveq,pc,lr)
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                add     r0, r2, #7
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                RETINSTR(mov,pc,lr)
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@ Purpose  : Find next 'zero' bit
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@ Prototype: int find_next_zero_bit(char *addr,int maxbit,int offset)
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                .globl  _find_next_zero_bit,find_next_zero_bit
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find_next_zero_bit:
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_find_next_zero_bit:
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                tst     r2, #7
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                beq     Lfindzbit1lp            @ If new byte, goto old routine
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                ldrb    r3, [r0, r2, lsr#3]
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                orr     r3, r3, #0xFF00         @ Set top bits so we wont get confused
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                stmfd   sp!, {r4}
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                and     r4, r2, #7
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                mov     r3, r3, lsr r4          @ Shift right by no. of bits
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                ldmfd   sp!, {r4}
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                and     r3, r3, #0xFF
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                teq     r3, #0xFF
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                orreq   r2, r2, #7
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                addeq   r2, r2, #1
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                beq     Lfindzbit1lp            @ If all bits are set, goto old routine
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                b       Lfoundzbit

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