Re: GS Emulator

[dempson@actrix.gen.nz (David Empson)]

In article <Ct70v9.94I@eskimo.com>, Erik Kloeppel <lurch@eskimo.com> wrote:
> In <CszD9A.n0L@actrix.gen.nz> dempson@actrix.gen.nz (David Empson) writes:
> 
> <The 65816 is certainly less complicated than the 68000 family.
> 
> <The IIgs hardware is probably a lot _more_ complicated than the Mac
> <hardware, due to the emulation of an Apple IIe (all of the bank
> <switching), the very messy and detailed I/O map, the video modes, and
> <particularly the Ensoniq sound chip.
> 
> seems to me, though, that is should be fairly possible to emulate the pure
> GS - (like Iknow what I'm talking about) Ignore  anything todo with P8
> and emulate only GS/OS.. 

Sorry, won't work.  Quite a lot of native IIgs stuff relies on code and
features in the emulated portion.  GS/OS boot sequence, interrupts,
serial port support, mouse support (on a ROM 1) come to mind.

GS/OS itself resides in the emulated language card space in banks $E0
and $E1.

Quite a lot of native IIgs text programs still use the emulated IIe
80-column firmware.

Anyway, if it can't run APPLEVISION, it isn't an Apple II.  :-)


You might be able to get away with limited emulation (e.g. not
supporting auxiliary memory bank switching might work).
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand