Re: 5.25 drive emulator

[rdippold@qualcomm.com (Ron "Asbestos" Dippold)]

stu1222@discover.wright.edu (General Unix Accounts) writes:
>So the next question is whether or not there is someone out there that
>would be interested in writing such an emulator?  I wish I could.

This is good, but we've still go the primary problem - trapping the
accesses.  He's using this in an emulator, so he can tell whenever an
I/O address is being accessed and say "Ahah!  This is a disk read."
As far as I know, there's nothing on the IIgs that can transfer
control to an interrupt handler or whatever when a specific address is
accessed. 

On the other hand, I think there's a trace bit of some sort in the
65816 that lets you get control before every single instruction.  I
suppose you could decode the instruction yourself and see if it could
possibly access the drive ports.  You'd have to emulate a 65816 in
software!  And probably would conflict like mad with interrupt
handlers or GS/OS.  But might be possible if my memory is correct.


-- 
Actual bureaucratic doublespeak:
  Career alternative enhancement program: firing workers