Re: Revisited: Sega XY freeplay

Oh, BTW, nice disassembly Dave!!! Looks pretty strange to a 6502 guy like me tho 8-)

ob non-vector... anyone here going to the pinball expo in Chicago this year (besides Jeff
A.)?

fishd wrote:
>
> At 11:10 AM 9/1/99 -0700, Clay wrote:
> >It's all software. You can find it pretty close to the beginning of the
> >code in Star Trek at least.
> > .snip.
> >Since I never seem to get around to this, I'll look for my disassemblies of
> >all the G-80 stuff. I think I noted the coin-timer in at least one...
> >Probably a two-byte patch to just jump over it...
> >
>
> Like Clay said it's all in software. I looked at it a long time
> ago when doing the security stuff so it all looks Greek now.
> Here's the routine from Space Fury. I'm seem to remember that it's
> the same for all games. Have fun!
>
> L0095: LD B,#E7 ;INT due to COINA or COINB
> L0097: IN A,(#F8) ;Check switch inputs, Active LOW
> AND D ;a = a .AND. /(initial input)
> JR NZ,#00A4 ;Don't JP if switch still pressed
>
> LD A,#A0 ;small delay
> L009E: DEC A
> JR NZ,#009E
> DJNZ #0097 ;keep looking for switch release
>
> DEC B ;Release Timeout, B = #FF
> L00A4: LD A,B ;switch released
> CP #C8 ;time the switch closure period
> JR NC,#00DA ;JP if timeout or period too short
>
> COINOK: CALL #010A ;period OK, CALL COIN_COUNTER_INCR
> LD BC,#04FB ;In_PORT = #FB, DIP switches
> LD L,#00
> LD E,L ;E & L = #00
> L00B2: IN A,(C)
> RRA ;Move DIP SW2-1 into E,b1
> RL E ;
> RRA
> RL L ;Move DIP SW2-5 into E,b0
> DEC C
> DJNZ #00B2 ;E(d3-d0) = SW2( 1,2,3,4 )
> LD A,L ;L(d3-d0) = SW2( 5,6,7,8 )
> CP E ;compare the two halves of the switch
> LD HL,#C80D
> JR Z,#00CB ;JP if SW2 positions identical
> BIT 7,D ;Complemented & Masked inputs, D7,6,5 of #F8
> JR NZ,#00CB ;D7 is COINA
>
> LD A,E ;SW2-1,2,3,4
> INC HL
> INC HL ;HL = #C80F
> .
> .
> .
>
> It goes on from here but that's the meat of it.
>
> David Fish | "We want...Information. INFORMATION
> Melrose, MA USA | You won't get it!
> fishd@tiac.net | By hook or by crook we will"
> dfish@bev.etn.com | _The Prisoner_
Received on Wed Sep 1 17:33:47 1999