0 REM THE TRANSACTOR VOLUME 6 ISSUE 02        PAGE 63
100 SYS700 ;PAL 64 ASM
110 .OPT OO
120 *=50000
130 ;VECTOR LINK EXAMPLE
131 ;VECTOR MANAGEMENT SYSTEM
132 ;SYS 50000,50003,50006 OR 50009
133 ;TO ACTIVATE OR DEACTIVATE ROUTINES
134 ;(EXAMPLES ARE IRQ-DRIVEN)
135 ;** SEE ARTICLE FOR DETAILS **
140 IRQVEC =$0314
150 JMP CONNECT ;CONNECT RTN1
160 JMP P1DIS   ;DISCONNECT RTN2
170 JMP P2CON   ;CONNECT RTN2
180 JMP P2DIS   ;DISCONNECT RTN2
190 ;
200 CONFLAG .BYT 0
210 CON2FLG .BYT 0
220 ;
230 P1DIS =*
240 JSR ADDCHECK ;VECTOR POINT TO RTN"?
250 BNE DERR     ;NO, CAN'T DISC[145]NECT
260 LDA C[145]FLAG  ;SEE [139] AL[135]Y SET[171]UP
270 BEQ P1E      ;AL[135]Y DISC[145]NECTED
280 SEI          ;OK, SET [164] PREV STATE
290 LDA #0
300 STA C[145]FLAG  ;CLEAR C[145]NECT FLAG
310 LDA OLDIRQ
320 STA IRQVEC
330 LDA OLDIRQ[170]1
340 STA IRQVEC[170]1
350 CLI
360 P1E RTS
370 ;
380 C[145]NECT [178][172]
390 LDA C[145]FLAG  ;AL[135]Y C[145]NECTED"?
400 BNE CERR     ;YES, ERROR
410 LDA #255
420 STA CONFLAG  ;SET CONNECT FLAG
430 LDA IRQVEC   ;SAVE OLD VECTOR
440 STA OLDIRQ
450 LDA IRQVEC+1
460 STA OLDIRQ+1
470 SEI          ;NOW CONNECT NEW RTN
480 LDA #<DISPLIN
490 STA IRQVEC
500 LDA #>DISPLIN
510 STA IRQVEC+1
520 CLI
530 RTS
540 ;
550 OLDIRQ .WOR *-*
560 ;
570 DERR =*
580 LDA #<DMSG: LDY #>DMSG
590 JSR $AB1E ;PRT STRING
600 RTS
610 DMSG .ASC "** CAN'T DISCONNECT **"
620 .BYTE 0
630 ;
640 CERR =*
650 LDA #<CMSG: LDY #>CMSG
660 JSR $AB1E ;PRT STRING
670 RTS
680 CMSG .ASC "** CAN'T CONNECT: ALREADY CONNECTED"
690 .BYTE 13,0
700 ;
710 ADDCHECK =*
720 ;SET Z IF IRVEC<>DISPLIN
730 LDA IRQVEC
740 CMP #<DISPLIN
750 BNE COUT
760 LDA IRQVEC+1
770 CMP #>DISPLIN
780 COUT RTS
790 ;
800 ;
810 DISPLIN =*
820 LDX #39
830 D1 =*
840 LDA MSG,X
850 STA $0400,X
860 LDA #1
870 STA $D800,X
880 DEX
890 BPL D1
900 JMP (OLDIRQ)
910 ;
920 MSG .ASC "*** ZAMSOFT OPERATING SYSTEM V 1.0 ***  "
930 ;
940 P2DIS =*
950 JSR P2CHK  ;POINTS TO RTN2"?
960 BEQ [172][170]5:JMP DERR;NO, CAN'T DISC[145]NECT
970 LDA C[145]2FLG
980 BEQ P2E       ;AL[135]Y DISC[145]NECTED
990 LDA #0
1000 STA C[145]2FLG  ;CLEAR C[145]NECT FLAG
1010 SEI
1020 LDA OLDIRQ2
1030 STA IRQVEC
1040 LDA OLDIRQ2[170]1
1050 STA IRQVEC[170]1
1060 CLI
1070 P2E RTS
1080 ;
1090 P2C[145] [178][172]
1100 LDA C[145]2FLG
1110 BEQ [172][170]5:JMP CERR
1120 LDA #255
1130 STA C[145]2FLG   ;SET C[145]NECT FLAG
1140 LDA IRQVEC
1150 STA OLDIRQ2
1160 LDA IRQVEC[170]1
1170 STA OLDIRQ2[170]1
1180 SEI
1190 LDA #[179]PROG2
1200 STA IRQVEC
1210 LDA #[177]PROG2
1220 STA IRQVEC[170]1
1230 CLI
1240 RTS
1250 ;
1260 OLDIRQ2 .W[176] [172][171][172]
1270 ;
1280 P2CHK [178][172]
1290 LDA IRQVEC
1300 CMP #[179]PROG2
1310 BNE POUT
1320 LDA IRQVEC[170]1
1330 CMP #[177]PROG2
1340 POUT [178][172]
1350 RTS
1360 ;
1370 PROG2 [178][172]
1380 LDA 197
1390 CMP LKEY
1400 BEQ P2OUT
1410 CMP #6
1420 BNE P2OUT
1430 INC $D020
1440 P2OUT [178][172]
1450 LDA 197: STA LKEY
1460 JMP (OLDIRQ2)
1470 ;
1480 LKEY .BYT [172][171][172]