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| From: pzsolt (all posts)
Date: 2000-08-15
Subject: Re: Interrupts again
|
Hi,
> For NMI this would be close (see the "64doc" file what happens if an NMI
> and an IRQ interrupt occur close to each other), but the IRQ input line is
> level-sensitive. It's not the state transition that activates the
> interrupt; in this model, the interrupt sequence could start whenever the
> I flag is clear and the IRQ_LINE variable equals true.
And if the IRQ routine does not acknowledge IRQ (IRQ_LINE is still 'low'),
after the IRQ routine the CPU will restart the IRQ sequence. Right?
And how does TED set IRQ line to high state? Which bit(s) of $FF09 makes this?
Only the 7th bit of $FF09?
And sorry for my 'lamer' questions, I want to know _everything_ about interrupts.
Greetings,
Zsolt
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