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From: tomp@pro-micol.cts.com (Tom Peng)
Newsgroups: comp.sys.apple2
Subject: Interrupt
Message-ID: <2253.apple2.info.apple@pro-micol>
Date: 30 Nov 90 18:07:20 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 23

Here is a question:
 
After witnessing GS playing music at the background, my adventurous mind began
to seek possibilities to create a music player for the 8-bits Apple IIs that
will play beep and buzz at the background like the GS. After a bit reading, I
came to the conclusion that the only way to do this is through some sort of
multitasking using an interrupt such as the VBL. It would be easy to do with
the GS since it has an vector which points to the subroutine that you want to
call when VBL is on. However, I was unable to find a vector that the Apple IIs
use for its VBL interrupt. As I recall, the Apple II mouse uses VBL interrupt
to update its stats, so perhaps there is a VBL vector for the Apple II as
well? Hmmm... I just want to write a music player, now I probably have to
write a full-blown multitasking application? Hmmm... anyone can help?

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Tom Peng
U. of Toronto Mechanical Engineering
InterNet: tomp@pro-micol.cts.com
          cindy@pnet91.cts.com

"Let's rewrite the Canadian constitution!!!"

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