Scott Dattalo wrote:
>
> On Fri, 21 Dec 2001, Don Hyde wrote:
>
> > indexlsb        equ     0x80
> > indexmsb        equ     0x81            ;table index is here
> > temp            equ     0x82
> >
> > lookup:
> >         movlw   low table
> >         addwf   indexlsb,w
> >         movwf   temp
> >         movfw   indexmsb
> >         skpnc
> >         incf    indexmsb,w
> >         addlw   high table
> >         movwf   PCLATH
> >         movfw   temp
> >         movwf   FSR
> >
> > table   retlw   1
> >         retlw   2
> >         ...
>
> Why not save a couple instructions:
>
>      movlw   HIGH(table)
>      addwf   indexmsb,w
>      movwf   PCLATH
>      movlw   LOW(table)
>      addwf   indexlsb,w
>      skpnc
>       incf   PCLATH,F
>      movwf   PCL
>
> But the table probably is accessed sequentially:
>
>      incf    PCLATH,F
>      incfsz  index,w
>      decf    PCLATH,F
>      movwf   index
>      movwf   PCL
>
> But even better IMO, is to use the 16F877 or similar flash device and
> store the table directly in ROM. One word holds 14-bits, 9 words hold 16
> bytes. Also, since this is a bit stream, you really don't have to worry
> about artificial byte boundaries.


Thanks for the input Don and Scott re the table!
That last idea is very nice Scott, thanks, I will
definitely implement that. Since the encoder
software outputs the sound wave data in .asm format
how would I go about using all 14 bits?

And any suggestions for reading bits squentially
from the program memory?? :o)
-Roman

PS. I have a couple of nice compression systems
also under test, they will go well with a 7bit
data unit size.

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