Subject:
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Re: signals / legOS internals
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Wed, 23 Jun 1999 03:48:35 GMT
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Viewed:
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1120 times
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Lou Sortman <theball@bigfoot.com> wrote:
> > When an interrupt occurs, the first thing that happens is that two data
> > values are pushed onto the stack. See pp. 68-71 and Fig 4-5 of the
> > hardware manual for more details.
>
> One of those being the program counter, and, I guess, the other being
> the status register. Such operation is typical.
>
> I guess I'm going to have to print that thing out.
Since it sounds like it might matter to you, I should point out that the
interrupt situation on the RCX is a bit more complicated than the H8 manual
makes it out to be. Interrupt vectors are in ROM, but the ROM does a
dispatch to interrupt vectors in RAM. The stack therefore has a bit more
on it than the H8 manual might suggest due to the fluff added by the
dispatch routine. Details are on the RCX Internals web pages and in the
LegOS sources, but of course feel free to ask for a description if you'd
rather not hunt around.
-Kekoa
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Message has 1 Reply:
 | | RE: signals / legOS internals
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| (...) Not to put too fine a point on it, and I hope Kekoa agrees, but the "fluff" is the reason why replacement firmware works in the first place. Without the ROM vectors being dispatched through RAM pointers that are initialized by the ROM and then (...) (25 years ago, 23-Jun-99, to lugnet.robotics.rcx.legos)
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Message is in Reply To:
| | Re: signals / legOS internals
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| (...) When you define a bunch of local variables (more than fit in available registers), where are they? Unless you happen to know the answer, I may have to do some more experimenting. Admittedly, it has been awhile, but the last time I was heavy (...) (25 years ago, 23-Jun-99, to lugnet.robotics.rcx.legos)
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