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From: Marko_Mäkelä
Date: 2001-07-24
Subject: Re: interrupt

On Tue, 24 Jul 2001, Hársfalvi Levente wrote:

> Now, whether the CPU actually fetches / executes one instruction from
> the main program after finishing the RTI command, or restarts the IRQ
> - register-save/jump - sequence immediately is just another question,
> I don't know (but AFAIK it is discussed in the 64doc mentioned
> earlier).

I think it will execute the instruction following the RTI, but I'm not sure. At least I can remember that it is possible to get an interrupt right after a SEI instruction (if the IRQ occurs 2 cycles before the end of the SEI execution). Similarly, an interrupt cannot occur right after a CLI instruction, unless interrupts were already enabled before the CLI was executed.

Marko