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Common ROM entry points?
- Subject: Common ROM entry points?
- From: steve@dosius.zzn.com (Dosius)
- Date: 6 May 2003 13:39:43 -0700
- Newsgroups: comp.sys.apple2
- Organization: http://groups.google.com/
- Xref: archiver1.google.com comp.sys.apple2:30223
When programs run on the Apple ][, occasionally they will need to call
the ROM to do things, and if the ROM isn't quite compatible, they will
fail. I would like to know if anyone has a comprehensive listing of
these entry points.
The ones I know are (note: some are in "signed int" decimal format and
some in hex, sorry!)
-936/$FC58 (CLRSCR)
-756 (GETCHR)
-1370 (REBOOT)
$FA62 (CTLRST) (Reset vector points here)
-1184 (SYSMSG)
-151 (JMPMON)
$FDED (?) (PUTCHR)
The reason for this is that, if somehow the logic of the ROM could be
mimicked without using actual ROM code, one could create a pseudo-ROM,
which could be loaded and run in an emulator, providing compatibility
for Apple ][ software. BTW the -1184 hook is not supported by
Laser-class clones, and even bugs up sometimes on the IIgs.
BTW, I cannot legally write this myself because I am tainted (three
bytes is three bytes!).
-uso.