Re: [cc65] sid-player.

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From: Ullrich von Bassewitz (
Date: 1999-12-01 09:22:11

> Okey, but i heard I had to make a irq player or something to make the
> sid file run/play. tell me more please :)

You don't need an IRQ player to play the SIDs. The only thing of importance is
that the play routine is called in regular intervalls. If your program manages
to call the routine without using an IRQ that's ok. Usually, things are
simpler if you use an IRQ handler, since you don't have to care about it, it
works in the background. But since a SID player has nothing to do apart from
playing the music, you may also do without. I'm pretty sure that SIDPLAY under
Linux does not use any interrupt...

Writing an IRQ handler is not too difficult, but it should be written in
assembler. You may call C functions from the assembler code, but this needs
special	precautions for reentrancy and is usually not worth the effort. If you
need sample code for a program that combines an IRQ handler written in ASM
with more code written in C, you may have a look at my morse trainer. The
source is available from


The actual tunes (three voices) are played by an IRQ handler in the
background, all other stuff (user interaction, precalculation, effects...) is
done in C.



Ullrich von Bassewitz                        
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