I would do it like:
    incf    bitIneed,W ; assume that bitIneed is between 0-7
    call    bittable
    iorwf   whatever,f ; can be and / xor etc
    ...

bittable
    addwf   PCL,f
    retlw   b'00000001'
    retlw   b'00000010'
    retlw   b'00000100'
    retlw   b'00001000'
    retlw   b'00010000'
    retlw   b'00100000'
    retlw   b'01000000'
    retlw   b'10000000'

...or
    clrf    bit  ; you can use WREG if your architecture allows that
    bsf     STATUS,C
shift
    rlf     bit
    decfsz  bitIneed
    goto    shift
    movf    bit,W
    iorwf   whatever,f ; again, replace it with and / xor ...

Maybe there are some more advanced techniques?

Tamas


On 10/08/06, Jinx <joecolquitt@clear.net.nz> wrote:
>
> How'd ya do it Steve ?
>
> Bob Ammerman gave this solution for 18F (where WREG
> is directly accessible). I use it often, with the routine name
> "bobbit" (not to be confused with John Wayne ....)
>
> example
>
>          movlw   b'00000110'  ;temp0 = 6
>          movwf   temp0
>
> bobbit   movlw   .1
>          btfsc   temp0,1
>          movlw   .4
>          btfsc   temp0,0
>          addwf   wreg,w
>          btfsc   temp0,2
>          swapf   wreg,w
>          movwf   temp1
>
> temp1 = b'01000000'. Gives you bit position 6 set for masking
>
> or for 16F
>
> http://www.piclist.com/techref/microchip/math/bit/setbit.htm
>
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>



-- 
unPIC -- The PIC Disassembler
http://unpic.sourceforge.net
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist