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Re: Faking RWTS13: Trying to figure out how to do something

On Mon, 28 Nov 2005, Michael J. Mahon wrote:


Trace it carefully, and you will see that it constructs a return address
on the stack than then RTSs to it.


Eek.


In fact, you may want to literally trace this code in an emulator.


OK.

Though, I think I see the code you're referring to:

        jsr     $FF58
        tsx
        lda     $0100,x         ; pick our address off the stack
        pha
        asl
        asl
        asl
        asl                     ; get slot number * 16
        sta     $2B
        tax
        lda     #$D0
        pha


Relocation to another page boundary should work as long as the code at
xxD1 is not moved or the constant $D0 pushed on the stack is adjusted
appropriately.


I was very careful to load it at 8x00 where x is the slot number.

Hm.
It seems to be jumping to the wrong address for some reason, and a trace doesn't seem to reveal why. 

-uso.