I think the fastest way would be to subtract 100 (0 1 or 2 times) to get the
most significant digit, leaving a number from 0-99, then look up the other
two digits in a table.  Sum total should be around two dozen cycles, and a
100-entry table for around 120-130 memory location.

Something like this...

(Scratched out fast, assumes the PCLATH already where it needs to be...
        no guarantees, not debugged or anything but should be about
close...)

        clrf    most_significant-digit
        movfw   number_to_convert
        sublw   d'100'
        skpnc           ;did I get the right carry state?
        goto    otherdigits
        incf    most_significant_digit,f
        sublw   d'100'
        skpnc
        goto    otherdigits
        incf    most_significant_digit,f
        goto    lookupothers
otherdigits:
        addlw   d'100'
        call    lookuplowdigits
        movwf   least_significant_2_digits
        ... all done

lookuplowdigits:
        addwf   PCL,f
        dt      0x00, 0x01, 0x02 ... 0x99


-----Original Message-----
From: Edson Brusque [mailto:brusque@FLYNET.COM.BR]
Sent: Wednesday, December 22, 1999 2:50 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Fast byte to BCD routine!


Hello PICsters!

    I'm needing a fast routine to break-down a byte to three digits:

        before:
        input = 137;

        after:
        output2 = 7;
        output1 = 3;
        output0 = 1;

    It doesn't have to be small, but it have to be FAST.

    I'm thinking about doing it with a BIG lookup-table. Anyone have a
better idea? Maybe a hybrid routine (table+calculations).

    Best regards and thanks for all your help,

    Brusque
___________________________________________________________________________
| | || |\| | || || |\|\ Edson :-^= Brusque
| | || ||| | || || |||| brusque@flynet.com.br
| |_||_||| |_||_||_|||| Musician, Programmer, Developer, Electronics
| \_\\_\|| \_\\_\\_\||| Blumenau / SC / Brazil / South America
|  |  |  |  |  |  |  ||    Earth / Solar System / Milk Way
|__|__|__|__|__|__|__|| Giro In'Italia homepage: www.flynet.com.br/giro
\__\__\__\__\__\__\__\| C.I.Tronics Lighting Designers: www.citronics.com.br
---------------------------------------- ICQ# 15937748 ---------------------
        Founder of the CUMP mailing list subscribe-cump@egroups.com
   Founder of the SoundFont mailing list soundfont-subscribe@onelist.com
----------------------------------------------------------------------------