[Coco] DELPHIterm Coco3 terminal program source

[Rick Adams]

At the last CocoFEST! Henry Rietveld helped me recover the source to my 
terminal program from an old floppy.  It was the second attempt; the 
files we read from the disk at the previous CocoFEST! turned out to be 
corrupt.  This time our luck was better.

In this particular case, I don't mind if people paw through my source 
code for historical or educational purposes.  The assembler source is 
available at:

http://rickadams.org/downloads/dterm.zip

I've been able to build it with lwasm; not having a RS232 pack, a modem, 
or even a POTS phone line to test with, I have no idea if it still works.

There are some keyboard and disk IO routines people might find 
interesting and/or useful.  They are complicated enough (plus not coded 
in my coding style) that I suspect they were donated by Dale Lear and/or 
possibly Marty Goodman.

An intriguing bit of trivia: at one point you will see two NOPs 
commented out right before the INCL of the disk IO code.  Those were 
used to alter the starting address of the disk IO routines to avoid an 
obscure and little-understood (by me, at least) bug in which disk IO 
would become unreliable if a certain key disk routine started on the 
"wrong" multiple of bytes in memory.  This was the cause of the BLOB 
(Boot Load Order Bug) known to those in the OS9 world back in the day.