In order to have a precise delay with this kind of routine:

tmr0_task_8      ;timer 0 = 0,5ms
     .....
        incf    Cnt,F        ;aux. reg.
        movfw   r1           ;1st stage of compare
        xorwf   Cnt,w        ; 0,5 x r1
        btfss   STATUS,Z     ;
        goto    _tmr0_task_8 ;
        clrf    Cnt          ;1st stage completed
                             ;
        incf    Comp,F       ;aux. reg.
        movfw   r2           ;2nd stage of compare
        xorwf   Comp,w       ;0,5 x r1 x r2
        btfss   STATUS,Z     ;
        goto    _tmr0_task_8 ;
        clrf    Comp         ;2nd stage completed
     ......
_tmr0_task_8


I have to find two registers value, r1 and r2, in a way that multiplied by a
constant match a value given by the program:

For example, I have a variable d'4140' and the constant 0.5.
need to find r1 and r2..., r1 and r2 must be integers from 0 to 255.

r1 x r2 x 0.5 = d'4140'

magic routine ===> r1=120 r2=69

120 x 69 x 0,5 = 4140

I have no approaches by now but divide, desperately, randomly, crazily 4140
by 255 to 0 hoping to find an integer residual between 255 and 0 :)

4140/(0,5*r1)=r2   r1=255?, no r1=254?, no..... :p

I'm studying Andy Warren delay methods to find an algorithm.

Regards,
Dennis.

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