On a PIC, the FSR is the equivalent of an index register. Point it to the
location you want to read or write, then read or write indf . The "pointed
to" location will be read or written. The 18f series has several fsr
registers. There are also registers that pre and post increment and
decrement, doing some of the work for you.

Harold

> Hi
>
> I'm using PIC16F628A.
>
> I've been wondering how would you move along a buffer/array, reading or
> writing to each location in a loop?  I can't see any obvious indirect
> memory
> access instructions in the reference manual.
>
> In my old 6502/'6510 assembler days I'd do something like (IIRC);
> LDA #0
> LDX #5
> loop:
> STA buffer_start,X
> DEX
> BNE loop
> ....
>
> Obviously, PIC only has the W register, and doesn't have index
> registers...Is
> there some 16-bit address to set, and some indirect instruction or
> something?
>
> cheers,
> Mark
>
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