[comp.sys.apple] Modifying ProDos quit code

mw22#@ANDREW.CMU.EDU.UUCP (02/25/87)

The ProDos quit code resides at $D100 to $D2FF on the second bank of the
language card.  The code from $D100 to $D126 does some handy reinitialization
stuff -- it turns off the language card, does a PR#0 and an IN#0, turns off
the 80-column card, turns on the alternate character set, turns off double
hires, and reinitializes the system bit map.

To make quit enter Applesoft, make quit jump to Applesoft's coldstart by
putting a JMP $E000 at $D127.  If you don't want all that initialization
stuff, at least preserve the first three items (i.e. killing the language
card and resetting I/O) or Applesoft won't work.

As far as I know, current versions of ProDos do not use the $D300 to $DFFF
area of the second bank of the language card for anything.


Michael Wertheim
(Carnegie Mellon University)