Hi gurus,

On a PIC16C84 I need to keep a table (32x8) of bits in ram,
and be able to change the state of each bit independently. Thus
I need to write indirectly to a bit in an indirectly addressed
register.

I have come up with the following code, but I am not sure it
is the best way of doing it. It seems 'clumsy'.

Anyone got any better ideas?

Regards,

Mike Watson.

--
mike@d-m-g.demon.co.uk





Byte   equ     0x0c            ;byte is table address + 0x10 (start
                               ;of table in RAM)
Bit    equ     0x0d            ;bit is 0..7
Cmd    equ     0x0f           ;Command plus bit storage. Defined below.

Data   equ     7h              ;

;The next section takes the byte and bit in the table from Byte
;and Bit and changes the appropriate bit to be the same as the
;databit in Cmd.

;
DoIt    movf    Byte,w
        movwf   fsr             ;Prepare for indirect bit set/clear.

        btfsc   Cmd, Data       ;
        goto    Set_Lo

Set_Hi  rlf     Bit,w         ;
        addwf   pc              ;relative jump to set correct bit
        bsf     0,0             ;
        goto    SR_Jump
        bsf     0,1
        goto    SR_Jump
        bsf     0,2
        goto    SR_Jump
        bsf     0,3
        goto    SR_Jump
        bsf     0,4
        goto    SR_Jump
        bsf     0,5
        goto    SR_Jump
        bsf     0,6
        goto    SR_Jump
        bsf     0,7
        goto    SR_Jump

Set_Lo  rlf     Bit,w         ;
        addwf   pc              ;relative jump to set correct bit
        bcf     0,0             ;
        goto    SR_Jump
        bcf     0,1
        goto    SR_Jump
        bcf     0,2
        goto    SR_Jump
        bcf     0,3
        goto    SR_Jump
        bcf     0,4
        goto    SR_Jump
        bcf     0,5
        goto    SR_Jump
        bcf     0,6
        goto    SR_Jump
        bcf     0,7
SR_Jump return