[Coco] Fooling around with assembly in RS-DOS environment

[William Astle]

On 2016-04-11 12:37, Arthur Flexser wrote:
> I seem to recall that unpatched Edtasm supports 80 columns as well, if you
> go to width 80 before booting it up, though my memory may be mistaken
> here.  Possibly there is an initial prompt whose response must be typed
> blindly before the 80 column screen comes up.  I might be confused between
> Disk and Rompack Edtasm versions, also.

Unpatched Disk EDTASM does work fine in 80 column mode if you do 
"WIDTH80" before running the "DOS" program. There is a blind prompt you 
have to answer to start it, but it's easy enough. You can "patch" it to 
autostart EDTASM without the prompt easily enough. (It involves editing 
or adding a single line in a basic program but I can't recall the details.)

The ROM version cannot work with the 80 column mode because the SECB 
support routines for 80 column mode are not present when the EDTASM ROM 
is so even if you disabled the autostart on the ROM, set WIDTH80, and 
launched it manually (EXEC&HE010), it will crash.

For anyone thinking they can fudge things by loading it from tape into 
the C000 range and then running it with the SECB stuff there will need 
to rethink that, too. The EDTASM ROM is larger than 8K so it won't fit 
in the C000-DFFF range.

The EDTASM ROM can, however, be saved as a disk file and loaded into, 
say, low RAM. A very minor patch to it to set the bottom of RAM and 
possibly the top of RAM (I can't remember the details there) will allow 
it to work. It turns out the ROM is position independent so the code 
itself runs fine. I used to do this back in the day. However, running 
this way you don't have the ability to save to disk so Disk EDTASM is 
still likely a better option if you have it.