Re: animation skip problem

[gt2011a@prism.gatech.EDU (gt2011a SIMMS,WILLIAM SHELDON)]

In article <C57A7F.nr@news.cso.uiuc.edu> ga56292@uxa.cso.uiuc.edu (Gregor Samsa) writes:

>just curious... Why not use cli? Is it because interrupts might be disabled
>when you do sei, or is there another reason?
>
>-George
> GeorgeA@uiuc.edu

The main reason I know of to use php/sei/plp instead of sei/cli is that
the first procedure saves the previous state of the interrupt bit on the
stack. If one routine disables interrupts and then calls another that
disables interrupts, etc., It would be most rude of a routine in the
middle of this call chain to re-enable interrupts when the routines that
called it expect interrupts to still be off. So instead you do the
php/sei/plp thing and instead of re-enabling interrupts, you just restore
the previous state. (Whatever it was).

-Sheldon


-- 
(Asked the novice): "And is the Tao in the DOS for a personal computer?"
The master coughed and shifted his position slightly. "The lesson is over
for today," he said.  +----------------------------------------------------
----------------------+   gt2011a@prism.gatech.edu / Sheldon Simms