Mac Emulate Amiga
7 messages in this thread
Ben, you ever heard the saying "any science of sufficient complexity is
indistinquishable from magic" or similar? Emulating Amiga in software
falls in that catagory, wouldn't it?
Tom
alternate: jonest@hfsi.com
I never met a man I didn't like…Will Rogers
If you want to read about magic software, check out the latest issue of Byte,
where an Apple engineer explains how they emulate the 68020 on the PowerPC, and
how new Apple executables can contain a mix of code with instructions from
either processor, as well as the Apple ROM itself containing 68020 and PowerPC
code.
Emulating the 68020 is certainly do-able these days. By replacing
functionality in Amiga system calls, as opposed to mimicking the raw assembly
code, it's more do-able. But many Amiga programs expect to write to memory
that's mapped to video. That takes another level of emulation beyond
instructions.
I stopped reading Byte a few years ago when they lost interest in what I
liked to do and went gung-ho on MsDos but I will try to find that issue
and review the article in the library. Just what we all need: more reading
lists 🙂 Why the 68020 specifically, is the 68030/40 a bit much then? It
would seem that the target should be the '040 at least (to play the latest
version of Wing Commander of course).
>many Amiga programs expect to write to memory that's mapped to video.
But don't Mac programs do MMIO video too? And IBM reserves A0000-BFFFF for
direct video mapping, so what makes our Chipram area any worse than the
rest to emulate? I thought the real problem was emulation of the custom
chipset surely?
Tom
alternate: jonest@hfsi.com
I never met a man I didn't like…Will Rogers
I wondered about MMU and FP support, too, but I think they handle that at other
levels within the emulation. Yes, IBMs and Macs use memory-mapped video, but
under Windows and Mac, you're supposed to use drivers to get to it. Yes,
emulating the Amiga chipset would be tough, too. I'm sure there's some real
zingers in that problem.
I've heard it – it was either Robert Heinlein or Arthur Clarke, if memory
serves. :^) And I agree with it.
But Emulating the Amiga in software wouldn't be quite that bad. Slow, yes.
:^)
–Ben
…via AutoPilot
Arther Clark…
-Tom-
"Any sufficiently advanced technology is indistinguishable from magic"
-Arthur C. Clarke
Chris – Fast and Low on my '020!
"Are we having fun yet?!?" -Anonymous A1200 User