[LMH]Microcode again... Status too this time! ^_^

[Nyef]

On Thu, 16 May 2002, Daniel Seagraves wrote:

> More stupid questions...
>
> How is the prefetch supposed to work?  Does setting the prefetch bit
> (Say, Prefetch-Field-Macro-Prefetch) automaticaly know the address
> I am prefetching from, or do I have to put the address somewhere
> first?  And which memory does it prefetch from?

Would %MBD-Location-Counter (an M-Memory functional destination) and
%MBS-Location-Counter (an M-Memory functional source), addresses 056 and
05 respectively, be what you're looking for in terms of an address? The
location counter is an offset in either words or half-words from the start
of the FEF, which is another set of M-Memory fields.

It's probably prefetching from mapped memory.

Huh. There are all sorts of interesting things in M-Memory...

> How is the ABV-Jump supposed to work? Say I set Jump-Field-Call-Illop -
> Does that immediately jump to 16 (Address-Call-to-Illop) or is there
> a trigger for it?

I was wondering about this myself. Could this be used in combination with
the bit that conditionally replaces part of the next instruction? That is,
you conditionally mask in some abv-jump?

> As of right now, only BYTE and ALU operations are completely decoded (but
> not all of the bits are handled yet).  I'm doing JUMP right now.
> Here's a snapshot of the output if anyonre cares: (It's trying to run the
> explorer 2 primitive microcode)

This is actually executing? Are you simulating the M-Memory functionality
or treating it as just a block of memory (or ignoring writes to that
space)? What about the NuBus I/O space?

I find it an interesting turnabout that _I'm_ the one writing the
higher-level emulator for once, and someone else is working closer to the
hardware level.

... OtakuWars!? (a few seconds with Google later) Oh my god, that's still
going?

---------------------------
All programming can be viewed as an exercise.
---------------------------
Alastair Bridgewater
e-mail: nyef@softhome.net