Would someone with a Quadra 700/900/950 be willing to test a program for me?

[dougg3]

Q700 with version 2.

Thanks for testing this again so quickly! This confirms that the Mac OS leaves the Q700’s $F29 register at 0 by default even though it doesn’t on the Q950. I have a feeling I might need to look at the $F09 register as well, at least on revision $B0. Maybe it’s the reason the IRQ is still firing even when I turn it off in $F29.

We are definitely seeing evidence of a repetitive EASC interrupt on the Q700 that doesn’t fire constantly, but does seem to keep going forever. But not on on the 950. Fascinating!

Maybe I need to print out all register values as part of the initial test. The Sound Manager must be setting up the 700’s EASC differently than the 950’s.

 

[cgp]

Thanks! That matches Callan's results, so there's definitely something different about the 700. If you would be willing to re-test with the new version as well, that would be awesome too!

Here's version 2 on my Q700 (with 7.6.1). Note not matching Callan's this time:

 

[dougg3]

Here's version 2 on my Q700 (with 7.6.1). Note not matching Callan's this time:

You're right! The difference is interesting. Yours has register $F29 as $01 when we start the test, which is what I would expect and what I've seen on every other model. Whereas Callan's is $00, which I've never seen before. It might be 7.6.1 versus a different OS version. I should probably print the system version in the test output.

The (3 2) versus (3 1) doesn't concern me a whole bunch. The 2 just means that two half-empty IRQs fired in succession really fast during your test, but not Callan's. The total count was still 3.

The interesting thing about this output from both 700s is that 237 + 3 = 240. The time that I wait during this portion of the test is 4 seconds, which is 240 ticks. It's almost like a sound IRQ is firing once per vertical refresh. I did observe in MAME while emulating a Quadra 700 that if I messed around in the Sound control panel a bit, I got it to spam writing 1 followed by 0 to register $F29 a bunch, which should cause the IRQ handler to re-fire. I should check to see if that code is originating from the VBL interrupt.

I am wondering if Apple has some kind of IRQ workaround in the Sound Manager that's implemented for the 700 but not for the 950. I'll keep investigating and thinking, and will eventually come up with a third version of the test to try.

Thank you both again for performing these tests!

 

[Callan]

I actually ran the test on two different quadra 700's, but i used the same boot image. The results were the same on both. I can try running the app on different os versions if you want me to. The 950 was running os 8 I believe (will check tonight).