Re: Ultima & Mockingboards on each of the Apples

["Great Hierophant" <great_hierophant@hotmail.com>]

MESS has separate ROMs for an Apple II and an Apple II+.  The Apple
II's are 4x2KB and the Apple II+'s 6x2KB (not counting the Disk33ROM
and the CHR ROM, which are shared.)  The Monitors for each are
conveniently contained in the f8 ROM.

The Apple II uses the Old Monitor ROM, as it starts in the monitor and
requires the user to reset to get to Integer BASIC.  According to the
Red Book, for the Old Monitor ROM the 6502 vectors are:
NMI - $03FB
RESET - $FF59
IRQ - $FA86

According to the Apple II Reference manual, the 6502 vectors for the
Autostart ROM in the Apple II+ should be:
NMI - $03FB
RESET - $FA62
IRQ - $FA40

The Apple II+ uses the Autostart ROM and initiates a reset sequence on
power-up.  But MESS's Apple II+ f8 ROM is identical to the last 2KB of
AppleWin's APPLE2.ROM.

The MESS and AppleWin ROMs use the proper vectors for the Apple II+
except their IRQ vector for the Apple II+ is $FF59, which does not lead
to the IRQ routine but the OLDRST routine.  Therefore, the Apple II+
ROM in MESS is clearly not from Apple.  I would hypothesize that it is
a hacked ROM designed for cracking games.

What else is wrong with these ROMs I cannot say, but they should be
replaced immediately.