AVR-Chat

Dave,

> Doesn't look entirely sane to me..

me neither, but does what I want, fetchs a BYTE from a lookuptable in memory
(on a page boundry I should add).

> Not sure what step is, but we are now pointing at high(Array*2)+Step

yep, Start of my table (array) and a certain number of bytes into it (step)

> Ok, adding offset, but this assumes that Step + num will never be > 255.

Huh?
The 'num' represents the table, there are 16 tables, each of 256 bytes.
so what I have is a value from -

(High(Array*2)+num)*256)+step

don't forget I add the tabel number to the 'upper byte'.

> What I would do, is this:
>
> ldi     zl,low(Array*2) ;Point at the array
> ldi     zh,high(Array*2)
>
> clr     TEMP2 ;or any suitable register
> add     zl,step         ;16 bit op
> adc     zh,TEMP2
>
> add     zl,num          ;16 bit op
> adc     zh,TEMP2

What that gives me is ;- (high(Array*2)*256)+step+num
errr, thats not going to do what I need, 'num' is a table number, as I say,
each table is 256 bytes long.

and you're right 'num' will never be more than 255, and neither will 'step'.

Paul