[Coco] Interrupt Vectors Physical Location ???

Arthur Flexser flexser at fiu.edu
Sat Dec 28 17:09:25 EST 2019


That would be $BFF2-BFFF in the Color Basic ROM.  No idea how the magic is
accomplished that causes them to appear at $FFF2-FFFF.

Art

On Sat, Dec 28, 2019 at 5:06 PM M. David Johnson <mdj at bds-soft.com> wrote:

> $FFF2 through $FFFF provide the CoCo's interrupt vectors, i.e. RESET, IRQ,
> SWI2, etc.
>
> Since these can't be changed, and are present the moment you turn the CoCo
> on, I'm guessing they're in ROM.
>
> But, physically where??
>
> I don't think they can be in any of the 8K ROM chips because none of those
> reach the $FFF2 address (although the BASIC ROM mirrors the vectors in
> $BFF2 through $BFFF).
>
> For example, if I wanted to jump to $0000 on startup instead of to $A027
> or $8C1B, which piece of hardware would I need to remove and replace?
>
> I've gone through the Unravelled books and the Technical Reference Manual.
> Am I perhaps just missing something?
>
> --
> M. David Johnson
> mdj at bds-soft.com
>
>
> --
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> Coco at maltedmedia.com
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>


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