Re: Instruction Set Architecture

[robin]

From: "Fred van der Windt" <fred.van.der.wi...@mail.ing.nl>
Sent: Thursday, 9 September 2010 3:02 PM

         LH    R1,=H'-4096'
         USING -4096,R1
         LA    R2,*
         LA    R3,-4(,R2)

What does R3 now address?

This caused a great deal of debate on this list several years
ago.  Very few contributors got it right.

I would assume that the last LA would just add 0000FFFC

Actually, it adds FFC.

to the contents of R2.

with the contents of R2.

But the contents of R2 seem undefined;

They are defined in the previous instruction, LA R2,*
which loads the content of the IAR into R2.