[stella] vcs.h: Incorrect constants?

Subject: [stella] vcs.h: Incorrect constants?
From: Erik Eid <eeid@xxxxxxxxx>
Date: Sun, 28 Jul 2002 10:06:55 -0400
I had some difficulty adding uses for the difficulty switches to my Euchre 
game yesterday.  I thought sure that I had the proper bit masks.

I looked at the vcs.h I picked up at http://www.io.com/~nickb/atari/doc/vcs.h 
and found this:

; Switch B equates
SWCHB   =  $0282
P0_Diff = $80
P1_Diff = $40
Con_Color  = $08
Con_Select = $02
Con_Start  = $01

It's also the same in Glenn Saunders' proposed standards constants file, 
vcsc.h (http://www.biglist.com/lists/stella/archives/200111/msg00427.html):

P0_Diff = $80
P1_Diff = $40

In the ASCII version of the Stella Programmer's Guide 
(http://www.io.com/~nickb/atari/doc/stella.txt), the section on SWCHB reads 
as follows:

  4.1 Port B - Console Switches (read only)
     Port B is hardwired to be an input port only that is read
     by addressing SWCHB (HEX 282) to determine the status of
     all the console switches according to the following table:

          Data Bit  Switch         Bit Meaning
          D7        P1 difficulty  0 = amateur (B), 1 = pro (A)
          D6        P0 difficulty       0 = amateur (B), 1 = pro
          D5/D4          (not used)
          D3        color - B/W    0 = B/W, 1 = color
          D2        (not used)
          D1        game select    0 = switch pressed
          D0        game reset     0 = switch pressed

It looks to me like the values of P0_Diff and P1_Diff are switched around in 

Am I reading this correctly or is there something I am missing?
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/

Current Thread