10 *= $033C
15 ;          JOYSTICK ID ROUTINE
20 ;
25 .O
30 .D JOYID.ML
35 ;
40 CONREG = $DC0D;     CONTROL REGISTER
45 PORTA = $DC00;      JOY PORT 2
50 PORTB = $DC01;      JOY PORT 1
55 KEYQUEUE = $00C6;      GUESS WHERE...
60 KEYBUF = $0277;        DITTO...
65 JOYNUM = $03A0;     RETURN VALUE
70 ;
100 JOYID LDA #$00;    GET STARTED
110 STA JOYNUM;        CLEAR RETURN VAL
120 STA KEYQUEUE;      CLEAR KEYBD BUF
130 LDA #$01;          SET UP VARIABLES
140 STA TEMP;             HOLDS VALUES
150 STA TEMP+1;           FROM CHECKS
160 LDA #$11;          KILL KEYBOARD IN
170 STA CONREG;           PREP TO READ
180 LDA #$FF;             JOYSTICK PORT
190 STA PORTA;            ONE
200 LDA PORTB;         READ JOY ONE
210 STA TEMP;          SAVE THE RESULT
220 LDA PORTA;         READ JOY TWO
230 STA TEMP+1;        AND SAVE IT
240 LDA #$81;          TURN ON THE
250 STA CONREG;           KEYBOARD
260 LDA KEYBUF;        CHECK KEYPRESS
270 CMP #$0D;             IS RETURN,
280 BNE CHKREGA;       NO RETURN, (null) ON
290 LDA #$00;          RETURN, LOAD JOY
300 STA JOYNUM;           VALUE WITH 0
310 BEQ RETURN;           AND EXIT
320 CHKREGA LDA TEMP;  COMPARE FOR FIRE
330 AND #$10;             BUTTON
340 BNE CHKREGB;       NO, JUMP AHEAD
350 LDA #$01;          LOAD JOY VALUE
360 STA JOYNUM;           WITH 1 AND
370 BNE RETURN;           EXIT
380 CHKREGB LDA TEMP+1;COMPARE FOR FIRE
390 AND #$10;             BUTTON
400 BNE JOYID;         NO, START OVER
410 LDA #$02;          LOAD JOY VALUE
420 STA JOYNUM;           WITH 2
430 RETURN LDA #$00;   READY TO RETURN
440 STA KEYQUEUE;         CLEAR QUEUE
450 RTS;               (null) ON HOME
460 TEMP .BYTE 1 1;    VARIABLES
470 ;
480 .END JOYID.LADS