Hi Peter and guys.

Couple final steps to bit my favorite 12 clocks/words. ;)
The code is not tested though...

;11 words/clocks asyncronous

        btfsc   direction       ;skip if dec
        comf    File,F          ;11->00
;
        movlw   2
        btfsc   base            ;skip if base_3
        movlw   3

        btfss   File,1
        btfsc   File,0
        movlw   -1

        addwf   File,F
;
        btfsc   direction       ;skip if dec
        comf    File,F          ;recover

Explanation:

-((-x-1)+a)-1 = x+1-a-1 = x - a


WBR Dmitry.



> Attempt to do some further steps in optimization...
> ( Cy polarity still depends from inc/dec , so use
> direction flag in addition to) Code is untested...
>
> #define File,3  base            ;0/1 base_3/base_4
> #define File,2  direction       ;0/1 dec/inc
>
> // inc(b3) -> if (File>=2) W=-2 else W=1 ;sub 2/-1
> // inc(b4) -> if (File==3) W=-3 else W=1 ;sub 3/-1
> // dec(b3) -> if (File==0) W=2 else W=-1 ;add 2/-1
> // dec(b4) -> if (File==0) W=3 else W=-1 ;add 3/-1
>
> ;15_Words/11_Clocks
>
>         movlw   2
>         btfsc   base            ;skip if base_3
>         movlw   3
>
>         btfsc   direction       ;skip if dec
>         goto    check_inc
>
> check_dec:
>
>         btfss   File,0
>         btfsc   File,1
>         movlw   -1

skip ( -1 ) if File==0


>
>         addwf   File,F
>         goto    all_done
>
> check_inc:
>         btfsc   base            ;avoid .0 check if base_3
>         btfsc   File,0
>         btfss   File,1
>         movlw   -1

skip ( -1 ) if File==3

>
>         subwf   File,F
>
> all_done:
>
> ;.....
>
> WBR Dmitry.
>
> > I feel that this can be improved probably by merging some shared parts of
> > the different blocks but it is fast enough as is and I have plenty of
> > space.
> >
> > And no, it's not a motor driver ;-).
> >
> > >>>>>>> previous posting, quoted
> > >;Base_3 inc / File 1.0 used, other bits are preserved
> > >;inc(0)=1 Cy=0, inc(1)=2 Cy=0, inc(2)=0 Cy=1, ...
> > >
> > >movlw   1
> > >btfsc   File,1  ; ==2? 2+1=3 -> 0
> > >movlw   -2
> > >addwf   File,F
> > >
> > >;Base_3 dec / File 1.0 used, other bits are preserved
> > >;dec(2)=1 Cy=1, dec(1)=0 Cy=1, dec(0)=2 Cy=0, ...
> > >
> > >movlw   2
> > >btfss   File,1 <----
> > >btfsc   File,0 <----
> > >movlw   -1
> > >addwf   File,F
> >
> > this is the neat eye-opener idea.
> > thank you very much,
> > Peter

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