On Mon, Feb 23, 2004 at 07:38:58PM -0500, Bob Ammerman wrote:
> Indeed you want to use the INDF/FSR technique.
>
> FSR is a 'pointer' to a memory location. You set FSR to point to the correct
> memory location, then reading or writing INDF really accesses the memory
> location pointed to be FSR.
>
> So, you can iterate thru a group of locations:
>
>  cblock 0x0C
>     foo:3
>     endfoo:0
>     cnt
>  endc
<snip code>

Hello Bob,

This works very well.  Specifying a register with :0 size is a neat trick.
It doesn't look like it takes up a GPR, yet I can use it to calculate
the size of my 'foo' array.  Does that sound correct?

(Is this documented anywhere?  I haven't come across any code that has
used this, and now I find myself wondering, what other data structures
access/manipulation techniques I may be unawares of)


> If the PIC you are using has an IRP bit in the status register you have to
> be sure it is correctly set, it is effectively an extra high it for the FSR
> register.

The datasheet for the 16f84a says 'The IRP bit is not used by the
PIC16F8x. IRP should be maintained clear'  Perhaps when I move on to
the bigger PICS, I will need to consider this.

Thanks.
-v

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