22 Apr
2007
22 Apr
'07
8:48 p.m.
On Sun, 22 Apr 2007, Chuck Guzis wrote:
Like what? CGA graphics starts at C800:0. The first
thing that I'd
do is search the executable for 00 C8 and see what referenced it. Be
aware that many early PC games used some pretty involved copy
protection, which might get in the way of brute-force hacking.
Otherwise, I'd just set up a TSR to examine some conventional DRAM at
C800 and update the 2000 display accordingly. You might even
fabricate a card that interrupts after an access to the screen
buffer, latching the address and data.
I think that you'd want to map your graphics emulator from B800.
Save C800 for hard disk emulators.
Writing PC emulators for incompatibles is certainly possible, but,
is it worth the effort.
Do a thorough plan of what you want to do with it. There may be easier
ways. For example, it was trivial to patch PC-Write to work with the
non-standard text video of the Toshiba T300.