Sky Travel
Notes by Nick Westgate

Astronomy program with map that omits NZ!
Two versions available on asimov:
1. SkyTravel.2mg: "IIgs compatible" cracked 800k 2mg (3.5" disk)
2. skytravelasronomy.dsk

Using the DSK produces a buzz in AppleWin; also mentioned by db on c.s.a2 - I think he was using a //c.

In its waiting for input loop it calls:

4234: AD 36 C0 LDA $C036
4237: 09 80    ORA #$80
4239: 8D 36 C0 STA $C036
423C: 60       RTS

and

423D: AD 36 C0 LDA $C036
4240: 29 7F    AND #$7F
4242: 8D 36 C0 STA $C036
4245: 60       RTS

It probably uses this to speed up slow tasks like computation and drawing.
Not sure why it bothers slowing down on a GS though.

Code above
found at track 7 sector D offset 34. (?)
Another copy
found at track 2 sector 2 offset C7: (?)

Created modified version for non-IIgs machines by NOPing out (#$EA) the accesses to $C036.
