One thing you could do is use the RETLW instruction:

  Call SetPortLookup
  Iorwf portimage,f
  Movf portimage,w
  Movwf portb
 . . .

SetPortLookup:
  Andlw 7    ; bit #s from 0 to 7 only
  Addwf PCL,F
  Retlw 1
  Retlw 2
  Retlw 4
  Retlw 8
  Retlw .16
  Retlw .32
  Retlw .64
  Retlw .128

A few notes:

.64 is decimal no matter what radix you are using by default.

I modified a variable rather than the port directly because of possible
problems with using read modify write instructions with a port. I try to
always write to a fake port register and then output the register
directly. Otherwise you could have said:

Iorwf portb,f

You can read more about this problem in the data sheet.

Also, you might enjoy http://www.al-williams.com/pictutor

Good luck!

Al Williams
AWC
* Easy RS-232 Prototyping
http://www.al-williams.com/awce/rs1.htm

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Daryl Sayers
> Sent: Wednesday, January 16, 2002 3:17 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: Beginners 16C84 programming question
>
>
> Sorry for not explaining my question correctly. What I REALLY
> wanted was to express the data between 0-7 as bit location to turn on.
>
> eg: if the data was 0x03 then I would turn on bit 3 of port B.
>
> The code snippet I gave showed this but my question was
> incorrect. I have since tried a few ideas and have come up
> with the following. I hope its not too repulsive.
>
>         ...
>         CALL    Setport
>         RETURN
>
> Setport
>         BCF     STATUS, C
>         RLF     DataByte, w
>         ANDLW   0fh
>         addwf   PCL,f
>         bsf     PORTB,0
>         RETURN
>         bsf     PORTB,1
>         RETURN
>         bsf     PORTB,2
>         RETURN
>         bsf     PORTB,3
>         RETURN
>         bsf     PORTB,4
>         RETURN
>         bsf     PORTB,5
>         RETURN
>         bsf     PORTB,6
>         RETURN
>         bsf     PORTB,7
>         RETURN
>
>
> > Do you mean:
> >    movf TmpByte,w
> >    movwf PORTB
>
> > Al Williams
> > AWC
> > * Floating point math for the Stamp, PIC, SX, or any
> microcontroller
> > http://www.al-williams.com/awce/pak1.htm
>
>
>
> >> -----Original Message-----
> >> From: pic microcontroller discussion list
> >> [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Daryl Sayers
> >> Sent: Monday, January 14, 2002 5:50 PM
> >> To: PICLIST@MITVMA.MIT.EDU
> >> Subject: Beginners 16C84 programming question
> >>
> >>
> >> I had a play with a 16C84 several years ago and I now need
> to make it
> >> do something. I am a real PIC beginner. My simple programming
> >> question is how do I represent a byte out to the RB port.
> It seems my
> >> restriction is using a variable in the bsf op code. I
> manually did it
> >> by doing each bit but I am sure there is a more elegant
> way of doing
> >> it through a loop. I am using gpasm-0.9.14 alpha to assemble code.
> >>
> >> movlw 0x01
> >> subwf TmpByte,w
> >> btfsc STATUS, Z
> >> bsf   PORTB,0
> >>
> >> movlw 0x02
> >> subwf TmpByte,w
> >> btfsc STATUS, Z
> >> bsf   PORTB,1
> >>
> >> ......
> >>
> >> movlw 0x80
> >> subwf TmpByte,w
> >> btfsc STATUS, Z
> >> bsf   PORTB,7
> >>
>
> --
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