[stella] Understanding the PIA

[Stephen Anthony]

On April 4, 2008 1:49:33 pm seagtgruff at aol.com wrote:
> I think I can run some tests tonight-- 2600, 7800, z26,?Stella-- and
> maybe even PCAE to boot! I'll test
>
> (1) all timer intervals (1, 8, 64, and 1024);
> (2) when the timer interrupt flag gets set;
> (3) how the timer decrements after first wraparound but before
> reading TIMINT; (4) how the timer decrements after first wraparound
> after reading TIMINT; (5) how the timer decrements after second
> wraparound but before reading TIMINT; (6) how the timer decrements
> after second wraparound after reading TIMINT.
>
> Can anyone think of anything else?

Any info you can provide is greatly appreciated.  If possible, please 
include as much detail as you can.  This 'bug' has been with Stella for 
years now, and I'd like to get it nailed once and for all.

Plus the fact that knowing how the real system actually works will help 
new developers (and perhaps old ones as well).

Steve