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):
;DIFFICULTY SWITCHES
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
(A)
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
vcs.h.
Am I reading this correctly or is there something I am missing?
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