Airwindows Catalina CPU Spike Bug Fix: various plugins

Hi! I'm Chris from Airwindows, and I've been grappling with a few Catalina-related problems. I'm here to talk about a specific one, and the solution I found that might help… and what that means.

Among the bad things happening to Logic users on Catalina, there's been a pesky bug, and it's not the first time I've heard of it. Ever since Spiral came out, there's been a few people saying 'hey, my CPU is spiking up for no reason and I can't use this'. Not always, but sometimes. There seemed no pattern to it.

Working on the Console7 release, this came up again, and I tried a fix, from which two people have now said their CPU spiking went away. Here's what changed: if I use the following line of code,

/ (inputSample == 0.0)? 1: fabs(inputSample)

the CPU can spike in Catalina, and if I change it to

/ (fabs(inputSample) == 0.0)? 1: fabs(inputSample)

that problem (during playback) stops happening.

If people get crashes during playback before, and that one change fixes it, it establishes that on normal versions of MacOS long double variables use the math library fabs() and correctly return the right number, or zero. And under Catalina, ANY USE of the math library fabs() on a long double can convert it to a double or maybe a float, where it becomes a zero if it's small enough, and then dividing by it crashes Logic or blows up the CPU.

If this was happening to you when trying the following plugins: ADT, BitGlitter, Channel6, Channel7, Channel8, Console7Buss, Console7Cascade, Console7Channel, Distortion, Focus, Holt, Pop, Spiral, Spiral2, Tape, or UnBox…

Download ZeroFix.zip to get new versions of ALL those plugins, for all formats (not just AU), in hopes this will help. I didn't get a lot of feedback beyond just a brief confirmation: the conversation immediately turned to Logic on Catalina crashing when windows are closed, and my plugins don't draw their own windows so there seems to be not a damn thing I can do about that.

My hope is that this bugfix for the above list of plugins dating back to 2018 (everything that's used the Spiral saturation algorithm) will prove useful. NewUpdates.zip now has the new versions too, and every direct download for the individual plugins are now the bugfix versions: if you use the same URL but append 'Zero' to the end (like, for BitGlitter.zip you'd make the URL say BitGlitterZero.zip) you can still get the original downloads exactly as they were.

This has been quite a shot in the dark, but if it turns out other people can reproduce the 'CPU spikes' in these plugins, and then find the spikes no longer happen with the bugfixes, we have learned something alarming: Catalina is capable of breaking MATH as defined in C++, by not overloading fabs() for long double word lengths. The fix really shouldn't work, because getting the absolute value of a long data word shouldn't truncate it to a shorter value.

But then, Logic should be able to close windows as well, and previously working versions of Logic have apparently taken to crashing over just that, with only the migration to Catalina as a change… or making much larger CPU demands when any plugin window is open. Methinks things have been changing under the hood, and I hope someone at Apple knows what they're doing. For now, I'm sticking to Mojave, which has been trouble-free (apart from making all my programs, non-Apple programs, hang on launch when the authentication server Apple never told me about, was down… but there's a way to tell Mojave not to do that, so the problem will not recur)

Busy week. Catch ya later cooge