I've never done it before, but I'd use a lookup table.
Just make sure you don't run off the end of the table.

        movlw   d'7'
        subwf   number,w        ;compare numbers
        SKPNC                   ;if number is larger than 7
        goto    ValueOutOfBounds ;do this!
        movlw number            ;else this.
        call    GetBitMask
        ;the correct bit mask will be in w now.
        ;rest of program.

ValueOutOfBounds
        error codehere.


GetBitMask
        addwf   PC,f
        retlw   b'00000000'
        retlw   b'00000001'
        retlw   b'00000010'
        retlw   b'00000100'
        retlw   b'00001000'
        retlw   b'00010000'
        retlw   b'00100000'
        retlw   b'01000000'
        retlw   b'10000000'




-Shane.


On Wed, 17 Sep 1997, Frank Dalton wrote:

> Using a PIC, has anybody figured out a good
> way to take a number from zero to seven (0 to 7)
> and use it to generate the corresponding bit
> mask (i.e., 00000001, 00000010, 00000100, etc.)?
>
> This is bound to be an old problem solved long
> ago by gurus more wiser than me.  Who has the
> best code snipet for doing this operation?
>
> --
> ------------------------------------------------------
>    /\         Frank Dalton (fdalton@pineinst.com)
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>  ///\\\       101 Industrial Drive
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>