Background Music

[tonyrocks]

Is it possible play sounds or background music using BASIC (and perhaps DATA) and not have the other basic routines get in the way?

[tlr]

Using only basic is hard but you can include a small ml-program in data statements which is poked in and started in the background with a sys.

[tonyrocks]

thanks TLR. Anybody have any examples?

[Mike]

In BASIC you'd need a main loop that's executed in a fairly regular manner. Not that hard to accomplish, as such a loop is a central element of most games. Getting a constant execution time for that loop is a little more difficult. That given, you'd just POKE the sound registers with new values upon each new main loop iteration.

Here's an example that plays a children's song alongside a well known animation from the VIC user's guide: (link)

With interrupts, and in machine language, it's much easier to do, obviously. Like thus (download):

Code: Select all

1 FORT=828TO939:READA:POKET,A:NEXT:SYS828
2 DATA 120,169,81,141,20,3,169,3,141,21,3,169,0,141,137,3,141,138,3,88,96,174,137,3,202
3 DATA 16,30,172,138,3,185,140,3,141,12,144,240,2,169,15,9,240,141,139,3,200,192,32,144
4 DATA 2,160,0,140,138,3,162,14,142,137,3,173,14,144,41,240,13,137,3,45,139,3,141,14
5 DATA 144,76,191,234,0,0,0,204,204,0,204,201,201,204,204,0,225,221,215,210,204,204,0
6 DATA 204,204,0,204,195,195,187,187,0,225,221,215,210,204,204,0

It's still (mostly) BASIC and DATA, so there you go.

[pixel]

In the end you'd have get hold of an assembly coder or – much, much better – you get into assembly yourself which is a very rewarding experience. The 6502 instruction set is poetry.

[tonyrocks]

thanks guys, you've been a big help. Im trying to push limits with BASIC for myself, but I'm finding it difficult to push where I want to go heh