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Old 16 August 2012, 23:18   #53
mc6809e
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Join Date: Jan 2012
Location: USA
Posts: 282
Quote:
Originally Posted by Toni Wilen View Post
I was too tired yesterday, I forgot that Amiga does not use autovectored interrupts, it uses "normal" interrupt acknowledge cycles.

Normal: normal memory cycle and fetches exception vector (from 0xfffff0 + interrupt number * 2 = end of ROM in Amiga)
Autovectored: E cycle and fetches interrupt number.
Thanks for this, Toni! All this time I thought "autovector" interrupts were genuine autovector interrupts. I see now from an old post of yours just how the method used by the Amiga works. The vector table entries for the autovector interrupts are simply reused for user interrupts.

Turns out the Amiga designers were even more clever than I had given them credit for.
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