Re: A83: Calculating this formula...


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Re: A83: Calculating this formula...




I am pretty sure that sla a is still better than add a,a... and srl is
shifting so there is no need to mask the upperbits...

David Phillips wrote:
> 
> If you're using the accumulator, you can save a byte and some cycles:
> 
>  add a,a    ; a *2
> 
> As for division, this will work, but remember that at the end you will need
> to mask off the upper bits:
> 
>  rra      ; a / 2
>  rra      ; a / 4
>  rra      ; a / 8
>  and %00011111        ; mask off top 3 bits since we shifted 3 times
> 
> > also remember that a / 2 or a * 2 is much faster with shift operations
> >
> > ie. sla a = a*2
> > srl a = a/2

-- 
Scott "_Wrath_" Dial
wrath@calc.org
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