Message-ID: <312@pucc-i>
Date: Tue, 12-Jun-84 11:54:17 EDT
Article-I.D.: pucc-i.312
Posted: Tue Jun 12 11:54:17 1984
Date-Received: Wed, 13-Jun-84 23:47:57 EDT
Organization: Purdue University Computing Center
Lines: 23

The //e ROM listings are in a 54-page supplement to the Apple //e Reference
Manual.  The supplement includes the new 80-column firmware and support
routines (Cxxx space), plus the //e version of the F8 ROM (but not Applesoft 
BASIC).

The Reference Manual itself costs about $50 and contains about 260 well-
written pages of useful information about the machine, the 80-column
cards, the bank switching, the soft switches, peripheral card conventions
and the interrupt system.

The ROM listings are complete with comments and (in the case of the F8 ROM)
conditional assembly directives to show the differences between the //e
and II+ versions.  The 80-column firmware has separate driver routines 
for Pascal and for Apple DOS, which share common subroutines.

One of the many things you can learn from studying the listings is that
interrupts are disabled part of the time during scrolling (long enough to
cause problems at 1200 baud).  In another article I'll describe how I got
around this problem, and a possible alternate approach.
-- 

Dave Seaman			"My hovercraft is full of eels."
..!pur-ee!pucc-i:ags