[stella] AARGH....obscure bug, or hardware glitch, help with final hour code review?

Subject: [stella] AARGH....obscure bug, or hardware glitch, help with final hour code review?
From: KirkIsrael@xxxxxxxxxxxxx
Date: 15 Mar 2004 05:33:13 -0000

Dang it, dang it, dang it!!!!!

Al put JoustPong on an EPROM.  

He reported two problems:
A. he started a "normal" game (vs fuji, no wall, just press reset), 
   finished it (thinks he won), and then claims select would just 
   not return to the title screen.
B. the select switch was jumpy, getting too many selects per press

Now, on further testing, he found out that the select switch on
that machine is twitchy, which would explain B.  But he still thinks
A. wasn't a hardware problem....I'm at a loss. It's not a problem I
ever saw, (or can repeat now) but I know I didn't always test playing 
full games and then going back.

So....I looked at the code (I think the relevant section SHOULD
be right after the MainLoop label, some fiddley 
lda SWCHB for reset, then lda SWCHB for Select....it seems
straightforward, but never say never.

So either it was 1. an intermitent hardware fault on an
already suspect machine 2. a really odd set of circumstances
that I can't duplicate 3. something different in Eprom land 
and/or 4. a minor problem, since I guess they could always just 
powercycle :-(  ...

So could people take a glance, see if there's ANYTHING dogey
or suspect in that?

there is one misleading comment , but over all,
the idea is if select wasn't hit (i.e. 
	lda SWCHB
	and #%00000010 ;is game select hit? **(misleading?)
	bne SelectWasNotHit ;if  jump to the title screen
it skips the initiations and gets on with the game, other
wise it initializes a bunch of stuff and then 
jums to TitleStart, the title screen...

Thanks for any advice.  Frickin' dodgey select switch....
I don't know how to debug this if it is a real problem

KirkIsrael@xxxxxxxxxxxxx    http://kisrael.com
 "The Wonder Twins had the right idea.  I defy you to think of any crisis 
  situation that would not be vastly improved by the presence of a gorilla 
  with a bucket of water."   --Maraud

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