Re: Question about 65816

From: Andre Fachat (
Date: 1998-07-10 09:31:53

Ruud Baltissen wrote:
> This also means that a RTI causes the CPU to return to the address
> represented by the dots in the first line after the BRK ($xx)
> instruction.
> Correct?

Right. The RTI instruction expects the _real_ ADDRESS of the address
to return to on the stack, _not_ ADDRESS-1 as RTS expects.
As BRK pushes the address of the BRK opcode+2, one could argue that
BRK is two bytes. When pulling the status register yourself then
BRK is even three bytes (using RTS)


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Andre Fachat, Institute of physics, Technische Universitšt Chemnitz, FRG
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