I'm trying to build a KA630 emulator, more because I think it'll be fun
and will teach me stuff than because I actually have a use for such a
thing (there are plenty of good open-source VAX emulators out there
already).  I picked the KA630 because it's the only VAX implementation
I have enough information on to even really attempt to build a
simulator for.

I dumped the ROMs from one of my KA630s (e/l/p/n:3fff 20040000, plus
some postprocessing of the capture file) to provide firmware.  But the
emulated VAX always hangs at selftest step B.  The manual I have
(EK-KA630-UG-001) says this means that the IPCR is not working properly
(probably broken Qbus electronics, on a real KA630), but it doesn't go
into enough detail for me to figure out what I'm simulating wrong.

Furthermore, if I break to the simulator and manually advance it past
the "blbc r0,." that it's hanging at, it continues, but ends up with an
error at step 7 - apparently it can't find any working memory(!).

I tried stepping through the code, but there are way too many small
routines called for unobvious reasons; I'd have to uncompile a
significant fraction of the code to suss it out that way.  And the
manual is not only unhelpful in these respects, it's known to be
outright _wrong_ sometimes; for example, there are some bits documented
as write-only which the ROM code depends on being able to read.

So I'm looking for someone who's enough of a KA630 guru to explain what
I'm getting wrong here, and is kind enough to do so.

Anyone?

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