Re: [colorforth] Why is interupts turned off after its code has been discarted by empt

[Samuel Falvo <falvosa@xxxxxxxxx>]

> empty empt logo cli ; macro
> Why is interupts turned off after its code has been discarted  by empt

ColorForth does not utilize interrupts for things like tending to the keyboard
or monitoring serial ports.  It doesn't need them, because it's software, and
the software usually written for it, is so simple.

When networking software is compiled, interrupts are required because of the
highly event-driven nature that networking requires.  Hence, they are enabled
only when networking software is being used.

EMPTY can be run at any moment, and not necessarily in response to a program
event.  Hence, when it runs, it has no idea whether or not networking software
is being run; therefore, it always makes sure that interrupts are turned off
just in case.

The original ColorForth (pre-networking) did not use CLI in the definition of
EMPT.  Hence its redefinition in the network code.  Later, it must have been
realized that, prior to loading the network application, the original EMPT
might be called in response to a user event even after the network application
is loaded.  This would leave interrupts enabled, and the interrupt vectors
pointing to software that doesn't technically exist anymore.  Hence, the odds
for crashing the system approaches near certainty unless interrupts are turned
off at the hardware level.  Hence the introduction of CLI.

--
Samuel A. Falvo II


__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com

---------------------------------------------------------------------
To unsubscribe, e-mail: colorforth-unsubscribe@xxxxxxxxxxxxxxxxxx
For additional commands, e-mail: colorforth-help@xxxxxxxxxxxxxxxxxx
Main web page - http://www.colorforth.com