Mole Attack

Mole Attack
Developer: HAL Laboratory Publisher: Commodore Platform: Commodore VIC-20 Released in US: 1981 This game has uncompiled source code.

Mole Attack is a historical footnote, in that it is one of the first major whac-a-mole games on computers.

Source Code

Starting around 0xD28 in the cartridge, there's a sizable amount of code.

START 
SEI
CLD
LDX #$FF
TXS
JSR ITINIT      ;INIT I/O PORTS
CLD
SEI
LDA #0 
STA VIA1+$E
LDA #%01111111  ;KILL INTERRUPTS
STA VIA2+$E
LDA #%00000000
STA VIA1+$B 
STA VIA2+$B 
LDA #%11111111
STA VIA2+2 
LDA #%10000000 
STA VIA1+3 
LDX #0
STX VIA1+4
INX
STX VIA1+5
LDA VIA1+$C
AND #%00111111
STA VIA1+$C
;
LDX #15         ;INIT VIC
VICILP LDA VICTBL,X 
STA VIC,X 
DEX )
BPL VICILP 
;
LDX #0          ;INIT ZERO PAGE 
TXA 
ZPINIT STA 0,X 
DEX 
BNE ZPINIT 
;
LDX #0          ;INIT CHARACTERS 
CHINIT LDA CHRTBL,X
STA CHAR,X 
LDA CHRTBL+$100,X 	
STA CHAR+$100,X
LDA CHRTBL+$200,X
STA CHAR+$200,X
LDA CHRTBL+$300,X
STA CHAR+$300,X
DEX 
BNE CHINIT 
;
LDX #0 
CHINT2 LDY #7
CHINT3 LDA $30*8+CHRTBL,X
EOR #$FF
STA $60*8+1+CHRTBL,X 
INX 
DEY
BNE CHINT3
INX
CPX #80 
BNE CHINT2 
;
; 
; 
JMP $AE00       ;TRANSFER TO
;                 TL/1 
VICTBL 
.BYT 3   ; X OFFSET
.BYT 18  ; Y OFFSET 
.BYT 22  ; X WIDTH
.BYT 50  ; Y WIDTH * 2
.BYT 0   ;
.BYT $EC ; 
.BYT 0   ; 
.BYT 0   ; 
.BYT 0   ;
.BYT 0   ;
.BYT 0   ; OSC 1 
.BYT 0   ; OSC 2
.BYT 0   ; OSC 3 
.BYT 0   ; NOISE 
.BYT $00 ; AUX.COL & VOLUME
.BYT $0D ; COLOR(BLACK+GREEN)

(Source: Chris Baird)