Re: The enhanced Apple//e's Assembler/Disassembler.

[dempson@actrix.gen.nz (David Empson)]

Dave Althoff <dalloff@freenet.columbus.oh.us> wrote:

> Klil N. (spamfree@poboxes.com) wrote:
> : Hello,
> : I stumbled into some kind of Asm/Dasm utility with a '*'
> : prompt.
> : I found that 'I' creates inverted text while 'N' turns it
> : back to normal. Could anyone please tell me of it's
> : commands?
> : Thank you kindly in advance,
> : Klil N.
> 
> Actually, that part is on ALL Apple ]['s, though there are subtle variations.
> 
> I:  Set text mode to INVERSE
> N:  Set text mode to NORMAL
> n^P:  Jump to $Cn00, where 0<=n<=7, effectively booting the device in that
>       slot

Not exactly.  It actually directs output to slot N, which happens to
cause a disk device in slot N to boot as soon as the prompt character is
displayed.

It is the equivalent of the PR#n command in BASIC, except that it will
usually cause DOS to be disconnected (if you direct output to a printer
card, for example).  The monitor equivalent of IN#n is n^K (K for
Keyboard).

My preferred method for booting a slot from the monitor is Cn00G (e.g.
C600G for slot 6).

> ^B:  Enter the current BASIC (Applesoft or Integer) (current program lost)

This also clobbers DOS and should be avoided.

> ^C:  Enter the current BASIC (Applesoft or Integer) (current program retained)
> ^Y:  Jump to the Monitor's user vector (I forget the address...)

$03F8.  (How I can remember trivia like this is beyond me...)  There is
room for a three byte instruction before you hit the NMI vector.

(Trivia: the IIe Technical Reference monitor listing mistakenly
describes this location as the "Applesoft USR function vector", which is
actually at $000A.)

> If you entered the Monitor from Integer BASIC, i.e....
> >CALL -151
> 
> then you have a couple of other features available, most notably...
> 
> *F666G
> which will take you to the Mini Assembler!

> EXCEPTION--Integer BASIC not required--
> The Mini-Assembler is back in the *enhanced* //e and in the IIgs (not sure
> about the //c).  From the Monitor prompt, just type the Mini-Assembler
> prompt--

The IIc has it in the "UniDisk" and later ROM versions (not the original
ROM that has a version number of 255).

> In the Apple ][ (NOT the ][+ or later), in addition to the "G" command,
> you could also use the "S"tep and "T"race commands for
> instruction-by-instruction debugging...the Monitor would show you the
> registers after each instruction.  As I have //e's and a IIgs, I've never
> used STEP and TRACE.

The ROM 3 IIgs monitor has a large set of debugging commands, that are a
subset of the GSBug command set, including step and trace facilities.
ROM 1 has hooks for step and trace commands, but there is no built-in
handler for them (they just print "Step" or "Trace").

The enhanced IIe does not have step or trace, but does have a simple
search command using 'S'.  I don't recall whether the IIc has
step/trace, but I doubt it.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand