Re: Out of Memory?

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

Bryan Parkoff <nospam@nospam.com> wrote:

>     I use ROM 00, ROM 01, and ROM 03 version of Apple IIgs.  I switch from
> Applesoft BASIC prompt to assembly prompt back and forth.  I type Applesoft
> BASIC commands such as HPLOT, CALL - 151 and/or HCOLOR.  I get error 
> message, "Out of memory error" from Applesoft BASIC prompt.
>     I don't believe that it has bad RAM chips.  It may be the routine bug on
> ROM.  I did try KEGS32 and the result is the same.  Do you have idea?

In some cases, you can get strange error messages from Applesoft BASIC
if you have entered BASIC without it being initialized correctly. This
isn't likely to happen on anything newer than the original Apple ][
(with Old Monitor ROM), as on that machine you start up in the monitor
and have to enter BASIC the first time using a special command. This is
done for you on later firmware or if you boot into ProDOS or DOS 3.3.

The most likely explanation is that while in the monitor, you have done
something which caused Applesoft BASIC's zero page variables to be
overwritten. When you enter BASIC again, it is confused and can't
process any commands correctly, resulting in a strange error message (in
this case "OUT OF MEMORY").

It might also be a problem with the stack pointer getting too close to
the bottom of the stack, particularly if you are calling subroutines
from the monitor using the 'G' command and returning to the monitor
using a BRK statement rather than RTS.

-- 
David Empson
dempson@actrix.gen.nz