Hi Scott.

16 perhaps ? :)


Scott Dattalo wrote:
> 
> One in particular takes 18 cycles.
> 
>         SWAPF   bin, W          ;w  = A0*16+A1
>         ADDWF   bin, W          ;w  = A0+A1
>         ANDLW   00001111b       ;w  = A0+A1 % 16
>         SKPNDC                  ;if A0+A1 > 16
>          ADDLW  0x16            ;  w  += 16

>>        SKPNDC                  ;if w % 16 > 10
>>         ADDLW  0x06            ;  w  += 6

With input value in range 00..63h(99.) I don't see the reason
why second skpndc check is required ? When dc flag is generated
in first instance maximum resulting value is 0x5 + 0xF = 0x14
I think these two lines can be safely omitted.


WBR Dmitry.

PS.

And final steps 0x40 -> 0x60 and 0x20 -> 0x30
are begging for some optimization as well. :)



>         ADDLW   0x06            ;w  += 6
>         SKPDC                   ;if w < 10
>          ADDLW  -0x06           ;  w  -= 6
> 
>         BTFSC   bin,4
>          ADDLW   0x16 - 1 + 0x6
>         SKPDC
>          ADDLW  -0x06
> 
>         BTFSC   bin, 5
>          ADDLW  0x30
> 
>         BTFSC   bin, 6
>          ADDLW  0x60
> 
>    ; result is in W
> 
> This was adapted from:
> http://www.piclist.com/techref/microchip/math/radix/b2bhp-8b3d.htm
> And the algorithm is described:
> http://www.piclist.com/techref/method/math/radixs.htm
> 
> Scott
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