Re: Apple II Speaker

[dalloff@gcfn.org (Dave Althoff Jr)]

M. Pender (mpender@hotmail.com) wrote:

: Bill, there's a trick I used to use that might help.  If you want to know
: what tones are being generated by calls to the ROM sound routine, it is
: possible to replace the routine on an Apple II+, IIe, IIc, or IIgs as long
: as it has at least 64k of memory.

: The idea is to save a copy of the Applesoft language to disk, modify the
: code on disk, rename the file "intbasic" and then use Loader.obj0 to load
: the code into the language card.

: Then when you type "INT", instead of changing over to integer basic, you
: will change over to your modified version of Applesoft.  Its also possible
: to do the same thing with memory moves, but I don't recall the sequence of
: softswitches.

: Anyhow, it would allow you to trap all calls to the sound generation routine
: in ROM, as well as the parameters passed to the routine.

Neat trick, except that it won't help.

There is no intrinsic tone generation routine in Applesoft.  Whatever
routine is being used, it isn't an Applesoft routine, it's gonna come with
the program playing the music.

Tone-playing routines are not difficult to write, but they tend to be
specialized, because sometimes a single delay loop isn't enough.

--Dave Althoff, ][.
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