[stella] SWCHA and Stella

[Ruffin Bailey <rufbo@xxxxxxxxxxx>]

Well, there's been so terribly much traffic on the list lately I thought 
I'd post my "latest findings".

I wrote a quick bit o' code to see if SWCHA was working the way it should 
on my Mac's RAsm/MacStella setup, and found something interesting.  It 
occurred to me earlier on that you could move the emulated joysticks in 
ways you could never more a real one (eg, right and left at the same 
time), so when my swcha test worked, I started playing around.

Turns out that you can get three directions out of each joystick at any 
one time with Stella, but only if you press the keys on the keyboard in 
the right order.  With the "player one joystick", if you move up-down (in 
any order) first, you can then add left but right will not register.  Or 
you can move right-left first (again both at the same time, whichever 
first) and then add down.  You cannot add up before or after down while 
holding down left & right. 

I won't bore you with the player two joystick, but a different pattern 
emerged.

Any reason it does this and is there any truth to this pattern with a 
real 2600?  

Well, sorry to keep all of you up late at night pondering these 
incredibly important questions!  ;)  But I thought it was neat.  I'm 
including swcha.bin in case there are others who can't sleep and want to 
stare at a blue strip until they see orange when they look away.  Anyway, 
all swcha.bin does is put swcha into grp0 and display it on the side of 
the screen.

Have fun, and I'm garnering more and more respect for Bob, Piero, Greg et 
al with every attempt to code this bugger!

Ruffin Bailey        |  Write Atari 2600 games on your Mac!
rufbo at cetlink.net |  http://members.aol.com/~mactari

Attachment: swcha.bin
Description: Mac BinHex archive