Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!dlyons
From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: Re: Interrupts & GS Sound Tools
Message-ID: <32346@apple.Apple.COM>
Date: 10 Jun 89 02:30:19 GMT
References: <6230034@hpindda.HP.COM>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 52

In article <6230034@hpindda.HP.COM> tribby@hpindda.HP.COM (David Tribby) writes:
>I'm working on a program that uses the GS Sound Tools, Note Synthesizer, and
>Note Sequencer. One part of the program moves waveforms in and out of
>DOC memory by calling the Sound Tool routines (MoveToRam, MoveFromRam?).
>The Toolbox Reference (Vol II) has a "Warning" that interrupts must be
>turned off while accessing the DOC RAM. My questions...
>
>   Which interrupts must be off? The Sequencer interrupts are off
>   during the moves, but do others have to be off as well?

It's saying interrupts *in general* should be off during this time, to insure
that nothing touches the sound chip in the middle of the operation.  In
other words, do a PHP, SEI to disable interrupts, and do a PLP to restore
interrupts to their previous state.

>   How does one turn interrupts off and on from TML Pascal? Miscellaneous
>   Toolset routine? Inline procedure to invoke machine code? Assembly
>   language subroutines?

There is no toolbox function to enable or disable interrupts.  The other two
options are fine.  In standalone TML Pascal, inline assembly code is easiest:

PROCEDURE PHP; INLINE $08;
PROCEDURE SEI; INLINE $78;
PROCEDURE PLP; INLINE $28;

Then you just use PHP, SEI, and PLP as procedure calls whenever you want.

PROCEDURE MyProcedure;
BEGIN
  PHP;
  SEI;
  DoSomeNiftyStuff;
  PLP;
END;

>   What happens if the interrupts are not off during the data moves?

Bad things.  Maybe.  Or maybe not.  Or maybe only after you give your
program to thousands of people.

>--Dave Tribby
>        ARPA: tribby%hpda@hplabs.HP.COM   UUCP: hplabs!hpda!tribby

 --Dave Lyons, Apple Computer, Inc.          |   DAL Systems
   AppleLink--Apple Edition: DAVE.LYONS      |   P.O. Box 875
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   My opinions are my own, not Apple's.