1000 SYS700
1010 ; * DYNABORDER           *
1020 ; * PAL SOURCE CODE      *
1030 ; * BY JEAN-YVES LEMIEUX *
1040 ; * RIMOUSKI (QC) DEC 88 *
1050 ; ************************
1060 ;
1070 .OPT OO
1080 ;
1090 TEM    =$254    ;TEMPORARY STORAGE
1100 IRQOLD =$257
1110 IRQVEC =$314    ;IRQ VECTOR
1120 RASHI  =$D011   ;RASTER LINE
1130 RASLO  =$D012   ;REGISTERS
1140 IRR    =$D019   ;INT. REQUEST REG
1150 IMR    =$D01A   ;INT. MASK REG
1160 BCOL   =$D020   ;BORDER COLOR
1170 ICR    =$DC0D   ;INT. CNTRL REG
1180 ;
1190 *=$3000
1200 ;
1210 SEI
1220 LDA IRQVEC      ;PREPARE NEW
1230 LDY IRQVEC+1    ;INTERRUPT
1240 STA IRQOLD      ;PROCEDURE
1250 STY IRQOLD+1
1260 LDA #<NEWIRQ
1270 LDY #>NEWIRQ
1280 DI STA IRQVEC
1290 STY IRQVEC+1
1300 CLI
1310 LDA #1          ;ENABLE RASTER
1320 STA IMR         ;LINE INTERRUPT
1330 STA IRR         ;RESET IRR
1340 LDA #$1B        ;CLEAR RASTER
1350 STA RASHI       ;COMPARE BIT (8)
1360 LDA #$7F        ;CLEAR IRQ
1370 STA ICR         ;FLAG BIT
1380 LDA #$00
1390 STA TEM         ;PREPARE
1400 STA TEM+2       ;SELF-MODIFYING
1410 LDA #$05        ;ROUTINE
1420 STA TEM+1
1430 LDA #$D7
1440 STA N6+1
1450 RTS
1460 ;
1470 NEWIRQ =*
1480 ;
1490 LDA #$32        ;FIRST INTERRUPT
1500 STA RASLO       ;AT LINE 50
1510 LDX #1          ;RESET
1520 STX IRR         ;REGISTER
1530 LDY #0
1540 N1 ADC #2       ;IF A RASTER LINE
1550 N2 CMP RASLO    ;HAS BEEN REACHED
1560 BNE N2          ;WE DISPLAY
1570 STX BCOL        ;A COLOR STRIPE
1580 N3 INX
1590 ADC TEM+1       ;SEPARATED BY
1600 N4 CMP RASLO
1610 BNE N4
1620 STY BCOL        ;A BLACK LINE
1630 N5 CPX #$05
1640 BNE N1
1650 BIT TEM
1660 BVS REST
1670 ;
1680 LDX #0          ;MODIFY PRIOR
1690 STX N5+1        ;ROUTINE
1700 LDX #$CA        ;'DEX' OPCODE
1710 STX N3
1720 N6 LDA #$00     ;DISPLAY BOTTOM
1730 STA RASLO       ;RAINBOW
1740 LDX #1
1750 STX IRR
1760 DEC TEM
1770 LDX #4
1780 BNE N1
1790 ;
1800 REST =*         ;RESTORE NEWIRQ
1810 ;                ROUTINE
1820 LDA #$E8        ;'INX' OPCODE
1830 STA N3
1840 LDA #5
1850 STA N5+1
1860 INC TEM
1870 LDA TEM+2
1880 BEQ R1
1890 SEC             ;MODIFY RASTER
1900 LDA N6+1        ;LINE VALUE
1910 SBC #4
1920 STA N6+1
1930 LDX TEM+1       ;AND STRIPE WIDTH
1940 INX
1950 CPX #$16
1960 BNE CIRQ
1970 INC TEM+2
1980 BEQ CIRQ
1990 R1 LDX TEM+1
2000 CLC
2010 LDA N6+1
2020 ADC #$04
2030 STA N6+1
2040 DEX
2050 BNE CIRQ
2060 DEC TEM+2
2070 ;
2080 CIRQ =*         ;CONTINUE IRQ
2090 ;
2100 STX TEM+1
2110 LDA #$30        ;NEXT RASTER LINE
2120 STA RASLO       ;INTERRUPT
2130 LDA #1
2140 STA IRR
2150 JMP (IRQOLD)
2160 DISABLE =*
2170 SEI
2180 LDA IRQOLD
2190 LDY IRQOLD+1
2200 JMP DI