Date   : Sat, 27 Dec 2008 10:17:10 -0000
From   : dl.harper@... (David Harper)
Subject: Using stack page for temp vars

Phill Harvey-Smith wrote:


> ...
> I have thought of using the bottom of the stack page starting at &100,
> for such a purpose, as tracing my code in the mess debugger the stack
> pointer always seems to be pretty near the top in the &1Ex area, so as
> long as I don't use too much stack they should never get overwritten.
> ...

One thing that hasn't been mentioned so far is that the lower part Page 1 is 
used by the MOS to store error messages before they are processed by the 
current language (or however they are to be dealt with).

ISTR also that location &128 and upwards (i.e. just above the aforementioned 
error message buffer) is used by the Tube host code. (I cannot remember 
exactly what for; I think it may be OSWORD blocks.)

Either of these might clash with your code (a) if  it might ever be called 
during error processing (or indeed if it might itself generate errors) or 
(b) if it were being used when the Tube is active.

David Harper