1MODE7
 10DIM XL 1, YB 1, XR 1, YT 1, Ydiff 1, offset 2, raster 3
 20DIM Code &700
 30byte = &80
 31rast=&82
 40FOR Pass = 0 TO 2 STEP 2
 50P% = Code
 60[OPT Pass
 80.InvRaster
 90 \ offset = (YT & (\7)) * 80
 100 Lda YT
 110 And #&F8
 120 Tay
 130 Lda Times80_lo,Y
 140 Sta offset
 150 Lda Times80_hi,Y
 160 Sta offset+1
 170 \ Ydiff + (YT & 7)
 180 Lda YT
 190 And #7
 200 Sta Ydiff
 210 \ offset = offset + XL*8
 220 Ldy XL
 230 Lda Times8_lo,Y
 240 Clc: Adc offset
 250 Sta offset
 260 Lda Times8_hi,Y
 270 Adc offset+1
 280 Sta offset+1
 290 \ offset = offset + &3000 {Screenbase}
 300 Adc #&30
 310 Sta offset+1
 320 \ X = XR-XL
 330Lda #19:Jsr &FFF4
 340 Lda XR
 350 Sec: Sbc XL
 360 Pha
 370 \ Y = YB - YT
 380 Lda YB
 390 Sec: Sbc YT
 400 Tay
 410 Iny
 420 \ FOR Y = Y TO 0 STEP -1
 430 .forY
 440 \ byte = offset
 450 Lda offset
 460 Sta byte
 470 Lda offset+1
 480 Sta byte+1
 490 \ FOR X = X TO 0 STEP -1
 500 Pla:Tax:Pha
 510 Tya:Pha
 520 Ldy Ydiff
 530 .forX
 540 \ offset?Ydiff = \offset?Ydiff
 550 Lda (byte),Y
 560 Eor #&FF
 570 Sta (byte),Y
 580 \ byte = byte + 8
 590 Lda byte
 600 Clc: Adc #8
 610 Sta byte
 620 Bcc nc1
 630 Inc byte+1
 640 .nc1
 650 \ NEXT X
 660 Dex
 670 Bpl forX
 680 Pla:Tay
 690 \ Ydiff = (Ydiff + 1) AND 7
 700 Lda Ydiff
 710 Clc: Adc #1
 720 And #7
 730 Sta Ydiff
 740 \ IF Ydiff = 0 THEN offset = offset + 640
 750 Bne not_next_block2
 760 Lda offset
 770 Clc: Adc #(640 MOD 256)
 780 Sta offset
 790 Lda offset+1
 800 Adc #(640 DIV 256)
 810 Sta offset+1
 820 .not_next_block2
 830 \ NEXT Y
 840 Dey
 850 Bne forY
 860 \ ENDPROC
 870 Pla \ X
 880 Rts
 910.ToRaster
 920 \ offset = (YT & (\7)) * 80
 930 Lda YT
 940 And #&F8
 950 Tay
 960 Lda Times80_lo,Y
 970 Sta offset
 980 Lda Times80_hi,Y
 990 Sta offset+1
 1000 \ Ydiff + (YT & 7)
 1010 Lda YT
 1020 And #7
 1030 Sta Ydiff
 1040 \ offset = offset + XL*8
 1050 Ldy XL
 1060 Lda Times8_lo,Y
 1070 Clc: Adc offset
 1080 Sta offset
 1090 Lda Times8_hi,Y
 1100 Adc offset+1
 1110 Sta offset+1
 1120 \ offset = offset + &3000 {Screenbase}
 1130 Adc #&30
 1140 Sta offset+1
 1150 
 1160 Lda raster
 1170 Sta rast
 1180 Lda raster+1
 1190 Sta rast+1
 1200 
 1210 \ X = XR-XL
 1230 Lda XR
 1240 Sec: Sbc XL
 1250 Pha
 1260 \ Y = YB - YT
 1270 Lda YB
 1280 Sec: Sbc YT
 1290 Tay
 1300 Iny
 1310 \ FOR Y = Y TO 0 STEP -1
 1320 .forY
 1330 \ byte = offset
 1340 Lda offset
 1350 Sta byte
 1360 Lda offset+1
 1370 Sta byte+1
 1380 \ FOR X = X TO 0 STEP -1
 1390 Pla:Tax:Pha
 1400 Tya:Pha
 1410 Ldy Ydiff
 1420 Lda rast
 1430 Sec: Sbc Ydiff
 1440 Sta rast
 1450 Lda rast+1
 1460 Sbc #0
 1470 Sta rast+1
 1480 .forX
 1490 \ offset?Ydiff = \offset?Ydiff
 1500 Lda (byte),Y
 1510 Sta (rast),Y
 1520 \ byte = byte + 8
 1530 Lda byte
 1540 Clc: Adc #8
 1550 Sta byte
 1560 Bcc nc3
 1570 Inc byte+1
 1580 .nc3
 1590 \ raster = raster + 1
 1600 Inc rast
 1610 Bne nc2
 1620 Inc rast+1
 1630 .nc2
 1640 \ NEXT X
 1650 Dex
 1660 Bpl forX
 1670 Pla:Tay
 1680 \ Ydiff = (Ydiff + 1) AND 7
 1690 
 1700 Lda rast
 1710 Clc: Adc Ydiff
 1720 Sta rast
 1730 Lda rast+1
 1740 Adc #0
 1750 Sta rast+1
 1760 
 1770 Lda Ydiff
 1780 Clc: Adc #1
 1790 And #7
 1800 Sta Ydiff
 1810 \ IF Ydiff = 0 THEN offset = offset + 640
 1820 Bne not_next_block3
 1830 Lda offset
 1840 Clc: Adc #(640 MOD 256)
 1850 Sta offset
 1860 Lda offset+1
 1870 Adc #(640 DIV 256)
 1880 Sta offset+1
 1890 .not_next_block3
 1900 \ NEXT Y
 1910 Dey
 1920 Bne forY
 1930 \ ENDPROC
 1940 Pla \ X
 1950 Rts
 1970.FromRaster
 1980 \ offset = (YT & (\7)) * 80
 1990 Lda YT
 2000 And #&F8
 2010 Tay
 2020 Lda Times80_lo,Y
 2030 Sta offset
 2040 Lda Times80_hi,Y
 2050 Sta offset+1
 2060 \ Ydiff + (YT & 7)
 2070 Lda YT
 2080 And #7
 2090 Sta Ydiff
 2100 \ offset = offset + XL*8
 2110 Ldy XL
 2120 Lda Times8_lo,Y
 2130 Clc: Adc offset
 2140 Sta offset
 2150 Lda Times8_hi,Y
 2160 Adc offset+1
 2170 Sta offset+1
 2180 \ offset = offset + &3000 {Screenbase}
 2190 Adc #&30
 2200 Sta offset+1
 2210 
 2220 Lda raster
 2230 Sta rast
 2240 Lda raster+1
 2250 Sta rast+1
 2260 
 2270 \ X = XR-XL
 2280Lda #19:Jsr &FFF4
 2290 Lda XR
 2300 Sec: Sbc XL
 2310 Pha
 2320 \ Y = YB - YT
 2330 Lda YB
 2340 Sec: Sbc YT
 2350 Tay
 2360 Iny
 2370 \ FOR Y = Y TO 0 STEP -1
 2380 .forY
 2390 \ byte = offset
 2400 Lda offset
 2410 Sta byte
 2420 Lda offset+1
 2430 Sta byte+1
 2440 \ FOR X = X TO 0 STEP -1
 2450 Pla:Tax:Pha
 2460 Tya:Pha
 2470 Ldy Ydiff
 2480 Lda rast
 2490 Sec: Sbc Ydiff
 2500 Sta rast
 2510 Lda rast+1
 2520 Sbc #0
 2530 Sta rast+1
 2540 .forX
 2550 \ offset?Ydiff = \offset?Ydiff
 2560 Lda (rast),Y
 2570 Sta (byte),Y
 2580 \ byte = byte + 8
 2590 Lda byte
 2600 Clc: Adc #8
 2610 Sta byte
 2620 Bcc nc5
 2630 Inc byte+1
 2640 .nc5
 2650 \ raster = raster + 1
 2660 Inc raster
 2670 Bne nc4
 2680 Inc raster+1
 2690 .nc4
 2700 \ NEXT X
 2710 Dex
 2720 Bpl forX
 2730 Pla:Tay
 2740 \ Ydiff = (Ydiff + 1) AND 7
 2750 
 2760 Lda rast
 2770 Clc: Adc Ydiff
 2780 Sta rast
 2790 Lda rast+1
 2800 Adc #0
 2810 Sta rast+1
 2820 Lda Ydiff
 2830 Clc: Adc #1
 2840 And #7
 2850 Sta Ydiff
 2860 \ IF Ydiff = 0 THEN offset = offset + 640
 2870 Bne not_next_block
 2880 Lda offset
 2890 Clc: Adc #(640 MOD 256)
 2900 Sta offset
 2910 Lda offset+1
 2920 Adc #(640 DIV 256)
 2930 Sta offset+1
 2940 .not_next_block
 2950 \ NEXT Y
 2960 Dey
 2970 Bne forY
 2980 \ ENDPROC
 2990 Pla \ X
 3000 Rts
 3020]
 3030[OPT Pass:.Times80_lo:]
 3040FOR Times = 0 TO 255
 3050 [OPT Pass
 3060 EQUB (Times*80) MOD 256
 3070 ]
 3080NEXT Times
 3090[OPT Pass:.Times80_hi:]
 3100FOR Times = 0 TO 255
 3110 [OPT Pass
 3120 EQUB (Times*80) DIV 256
 3130 ]
 3140NEXT Times
 3150[OPT Pass:.Times8_lo:]
 3160FOR Times = 0 TO 255
 3170 [OPT Pass
 3180 EQUB (Times*8) MOD 256
 3190 ]
 3200NEXT Times
 3210[OPT Pass:.Times8_hi:]
 3220FOR Times = 0 TO 255
 3230 [OPT Pass
 3240 EQUB (Times*8) DIV 256
 3250 ]
 3260NEXT Times
 3270NEXT Pass
 3271MODE1
 3280PRINT~&700-(P%-Code);" bytes free."
 3290?XL=32
 3300?YB=63
 3310?XR=48
 3320?YT=56
 3321!raster = &4000
 3330REPEAT
 3340?XL=((?XL)+1) MOD 80
 3350?XR=(?XL+8) MOD 80
 3360?YT=(?YT)+8
 3370?YB=(?YT)+32
 3380CALL InvRaster
 3390CALL InvRaster
 3400UNTIL NOT INKEY(0)