Re: Sound Manager & MIDI callbacks, interrupts and threads
Re: Sound Manager & MIDI callbacks, interrupts and threads
- Subject: Re: Sound Manager & MIDI callbacks, interrupts and threads
- From: "AUDIOSYNTH.COM" <email@hidden>
- Date: Sat, 16 Feb 2002 12:33:46 -0600 (CST)
On Sat, 16 Feb 2002, Andy Robinson wrote:
>
Both these callbacks communicate with the main app code via queues, so
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there are brief moments of queue-manipulation when it would be fatal for
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one to interrupt the other and access the queue.
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>
On classic Mac (AFAI understand it) these callbacks were called at
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"interrupt time" so there was never any danger of the main app
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interrupting the callback. To prevent the callback interrupting the main
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app I would briefly disable interrupts using InterruptDisableLib.c as
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provided by Apple. This uses assembly code which doesn't work on Mach-O.
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I'm not at all clear what the situation is now. Is the callback running
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in some pre-emptive thread? Do I need to worry about the main app
The situation now is that Apple sells dual processor machines, so
even with one processor interrupted the other could be mucking with your queue.
If you have two threads that need to write or read to another thread then
you need two fifos. Else you're not safe. You should not acquire a lock in
a callback.
--- james mccartney
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