Mike Watson wrote:

> 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

Your code is 41 words; the following code is 14 words.
Your code executes in fewer cycles, and is constant time,
this code takes longer depending on the bit number. A retlw
table could be used to do the bit number to bit mask
conversion if constant time is important.

;Note that this destroys the contents of Bit

doit
        movf    Byte,w
        movwf   FSR
        clrw
        bsf     STATUS,0        ;set carry
        incf    Bit             ;pre-inc
loop
        rlf     Bit             ;rotate mask
        decfsz  Bit,loop
        btfsc   Cmd, Data       ;what to do?
        goto    Set_Lo
        iorwf   0               ;or bit into byte
        return
Set_Lo
        xorlw   0ffh            ;invert w
        andwf   0               ;set bit low
        return


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 Clyde Smith-Stubbs       | HI-TECH Software,       | Voice: +61 7 3300 5011
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