Mail Archives: djgpp/1998/02/10/22:05:04
From: | jerry AT eteklabs DOT nospam DOT com (Scott "Jerry" Lawrence)
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Newsgroups: | comp.os.msdos.djgpp
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Subject: | Re: Allegro: Adding background music to old DOS game
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Date: | Tue, 10 Feb 1998 10:29:58 -0500
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Message-ID: | <MPG.f4a3c8070dde98f9896e6@gateway>
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References: | <6bphi4$8r6$1 AT fu-berlin DOT de>
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Organization: | e-TEK Labs
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NNTP-Posting-Host: | dial-q-14.netacc.net
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Lines: | 32
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To: | djgpp AT delorie DOT com
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DJ-Gateway: | from newsgroup comp.os.msdos.djgpp
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In the past, brenner AT biochem DOT mpg DOT de thusly spoke...
> [ ... ]
>
> Now I'm a beginner in coding DOS system functions (though I did quite some
> extensive Assembler programming on the Amiga some years ago) and after trying
> to grasp the basic concepts of the Allegro library I concluded it would be a
> wise idea to ask the professionals if this is possible using Allegro/djgpp at
> all :) From what I learned so far it's pretty tricky to do complex tasks like
> changing the running song in the MIDI routines *from out of an interrupt*, can
> you give me some suggestions as how to do this? (Can I call the play_midi()
> function from out of an interrupt handler? I'm pretty sure, I can't ;) Is
> there an easy way to do this anyway?) How about the 0x21/open interrupt. Do I
> use Allegro's _install_irq() routine to install my own handler?
Now i'm not positive about any of this, but chances are that Ultima grabs
all the hardware it can - including the timer interrupt (IRQ 0 i believe)
which is also mirrored at int 1ch. My guess is that Ultima mucks with
these, disabling any previously installed handlers.
another thing to look out for is if you're using a soundblaster, there's
a possibility that allegro will lock the hardware, so ultima will have
no sound whatsoever.
you might want to try making a simple TSR using allegro (which will end
up taking a large chunk of conventional memory i would think.) that just
plays a note every half second or so... then run ultima. you'd know
right away if it would work. THere are docs on the net about making
TSRs in DJGPP.
or i could be wrong...
-jerr
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