S-C DocuMentor — Applesoft
SAVE S.F3D8
1010 *--------------------------------
1020 * "HGR" AND "HGR2" STATEMENTS
1030 *--------------------------------
F3D8- 2C 55 C0 1040 HGR2 BIT SW.HISCR SELECT PAGE 2 ($4000-5FFF)
F3DB- 2C 52 C0 1050 BIT SW.MIXCLR DEFAULT TO FULL SCREEN
F3DE- A9 40 1060 LDA /$4000 SET STARTING PAGE FOR HIRES
F3E0- D0 08 1070 BNE SETHPG ...ALWAYS
F3E2- A9 20 1080 HGR LDA /$2000 SET STARTING PAGE FOR HIRES
F3E4- 2C 54 C0 1090 BIT SW.LOWSCR SELECT PAGE 1 ($2000-3FFF)
F3E7- 2C 53 C0 1100 BIT SW.MIXSET DEFAULT TO MIXED SCREEN
F3EA- 85 E6 1110 SETHPG STA HGR.PAGE BASE PAGE OF HIRES BUFFER
F3EC- AD 57 C0 1120 LDA SW.HIRES TURN ON HIRES
F3EF- AD 50 C0 1130 LDA SW.TXTCLR TURN ON GRAPHICS
1140 *--------------------------------
1150 * CLEAR SCREEN
1160 *--------------------------------
F3F2- A9 00 1170 HCLR LDA #0 SET FOR BLACK BACKGROUND
F3F4- 85 1C 1180 STA HGR.BITS
1190 *--------------------------------
1200 * FILL SCREEN WITH (HGR.BITS)
1210 *--------------------------------
F3F6- A5 E6 1220 BKGND LDA HGR.PAGE PUT BUFFER ADDRESS IN HGR.SHAPE
F3F8- 85 1B 1230 STA HGR.SHAPE+1
F3FA- A0 00 1240 LDY #0
F3FC- 84 1A 1250 STY HGR.SHAPE
F3FE- A5 1C 1260 .1 LDA HGR.BITS COLOR BYTE
F400- 91 1A 1270 STA (HGR.SHAPE),Y CLEAR HIRES TO HGR.BITS
F402- 20 7E F4 1280 JSR COLOR.SHIFT CORRECT FOR COLOR SHIFT
F405- C8 1290 INY (SLOWS CLEAR BY FACTOR OF 2)
F406- D0 F6 1300 BNE .1
F408- E6 1B 1310 INC HGR.SHAPE+1
F40A- A5 1B 1320 LDA HGR.SHAPE+1
F40C- 29 1F 1330 AND #$1F DONE? ($40 OR$60)
F40E- D0 EE 1340 BNE .1 NO
F410- 60 1350 RTS YES, RETURN
1360 *--------------------------------
1370 * SET THE HIRES CURSOR POSITION
1380 *
1390 * (Y,X) = HORIZONTAL COORDINATE (0-279)
1400 * (A) = VERTICAL COORDINATE (0-191)
1410 *--------------------------------
F411- 85 E2 1420 HPOSN STA HGR.Y SAVE Y- AND X-POSITIONS
F413- 86 E0 1430 STX HGR.X
F415- 84 E1 1440 STY HGR.X+1
F417- 48 1450 PHA Y-POS ALSO ON STACK
F418- 29 C0 1460 AND #$C0 CALCULATE BASE ADDRESS FOR Y-POS
F41A- 85 26 1470 STA MON.GBASL FOR Y=ABCDEFGH
F41C- 4A 1480 LSR GBASL=ABAB0000
F41D- 4A 1490 LSR
F41E- 05 26 1500 ORA MON.GBASL
F420- 85 26 1510 STA MON.GBASL
F422- 68 1520 PLA (A) (GBASH) (GBASL)
F423- 85 27 1530 STA MON.GBASH ?-ABCDEFGH ABCDEFGH ABAB0000
F425- 0A 1540 ASL A-BCDEFGH0 ABCDEFGH ABAB0000
F426- 0A 1550 ASL B-CDEFGH00 ABCDEFGH ABAB0000
F427- 0A 1560 ASL C-DEFGH000 ABCDEFGH ABAB0000
F428- 26 27 1570 ROL MON.GBASH A-DEFGH000 BCDEFGHC ABAB0000
F42A- 0A 1580 ASL D-EFGH0000 BCDEFGHC ABAB0000
F42B- 26 27 1590 ROL MON.GBASH B-EFGH0000 CDEFGHCD ABAB0000
F42D- 0A 1600 ASL E-FGH00000 CDEFGHCD ABAB0000
F42E- 66 26 1610 ROR MON.GBASL 0-FGH00000 CDEFGHCD EABAB000
F430- A5 27 1620 LDA MON.GBASH 0-CDEFGHCD CDEFGHCD EABAB000
F432- 29 1F 1630 AND #$1F 0-000FGHCD CDEFGHCD EABAB000
F434- 05 E6 1640 ORA HGR.PAGE 0-PPPFGHCD CDEFGHCD EABAB000
F436- 85 27 1650 STA MON.GBASH 0-PPPFGHCD PPPFGHCD EABAB000
F438- 8A 1660 TXA DIVIDE X-POS BY 7 FOR INDEX FROM BASE
F439- C0 00 1670 CPY #0 IS X-POS < 256?
F43B- F0 05 1680 BEQ .2 YES
F43D- A0 23 1690 LDY #35 NO: 256/7 = 36 REM 4
1700 * CARRY=1, SO ADC #4 IS TOO LARGE;
1710 * HOWEVER, ADC #4 CLEARS CARRY
1720 * WHICH MAKES SBC #7 ONLY -6
1730 * BALANCING IT OUT.
F43F- 69 04 1740 ADC #4 FOLLOWING INY MAKES Y=36
F441- C8 1750 .1 INY
F442- E9 07 1760 .2 SBC #7
F444- B0 FB 1770 BCS .1
F446- 84 E5 1780 STY HGR.HORIZ HORIZONTAL INDEX
F448- AA 1790 TAX USE REMAINDER-7 TO LOOK UP THE
F449- BD B9 F4 1800 LDA MSKTBL-$100+7,X BIT MASK
F44C- 85 30 1810 STA MON.HMASK
F44E- 98 1820 TYA QUOTIENT GIVES BYTE INDEX
F44F- 4A 1830 LSR ODD OR EVEN COLUMN?
F450- A5 E4 1840 LDA HGR.COLOR IF ON ODD BYTE (CARRY SET)
F452- 85 1C 1850 STA HGR.BITS THEN ROTATE BITS
F454- B0 28 1860 BCS COLOR.SHIFT ODD COLUMN
F456- 60 1870 RTS EVEN COLUMN
1880 *--------------------------------
1890 * PLOT A DOT
1900 *
1910 * (Y,X) = HORIZONTAL POSITION
1920 * (A) = VERTICAL POSITION
1930 *--------------------------------
F457- 20 11 F4 1940 HPLOT0 JSR HPOSN
F45A- A5 1C 1950 LDA HGR.BITS CALCULATE BIT POSN IN GBAS,
F45C- 51 26 1960 EOR (MON.GBASL),Y HGR.HORIZ, AND HMASK FROM
F45E- 25 30 1970 AND MON.HMASK Y-COOR IN A-REG,
F460- 51 26 1980 EOR (MON.GBASL),Y X-COOR IN X,Y REGS.
F462- 91 26 1990 STA (MON.GBASL),Y FOR ANY 1-BITS, SUBSTITUTE
F464- 60 2000 RTS CORRESPONDING BIT OF HGR.BITS
2010 *--------------------------------
2020 * MOVE LEFT OR RIGHT ONE PIXEL
2030 *
2040 * IF STATUS IS +, MOVE RIGHT; IF -, MOVE LEFT
2050 * IF ALREADY AT LEFT OR RIGHT EDGE, WRAP AROUND
2060 *
2070 * REMEMBER BITS IN HI-RES BYTE ARE BACKWARDS ORDER:
2080 * BYTE N BYTE N+1
2090 * S7654321 SEDCBA98
2100 *--------------------------------
2110 MOVE.LEFT.OR.RIGHT
F465- 10 23 2120 BPL MOVE.RIGHT + MOVE RIGHT, - MOVE LEFT
F467- A5 30 2130 LDA MON.HMASK MOVE LEFT ONE PIXEL
F469- 4A 2140 LSR SHIFT MASK RIGHT, MOVES DOT LEFT
F46A- B0 05 2150 BCS LR.2 ...DOT MOVED TO NEXT BYTE
F46C- 49 C0 2160 EOR #$C0 MOVE SIGN BIT BACK WHERE IT WAS
F46E- 85 30 2170 LR.1 STA MON.HMASK NEW MASK VALUE
F470- 60 2180 RTS
F471- 88 2190 LR.2 DEY MOVED TO NEXT BYTE, SO DECR INDEX
F472- 10 02 2200 BPL LR.3 STILL NOT PAST EDGE
F474- A0 27 2210 LDY #39 OFF LEFT EDGE, SO WRAP AROUND SCREEN
F476- A9 C0 2220 LR.3 LDA #$C0 NEW HMASK, RIGHTMOST BIT ON SCREEN
F478- 85 30 2230 LR.4 STA MON.HMASK NEW MASK AND INDEX
F47A- 84 E5 2240 STY HGR.HORIZ
F47C- A5 1C 2250 LDA HGR.BITS ALSO NEED TO ROTATE COLOR
2260 *--------------------------------
2270 COLOR.SHIFT
F47E- 0A 2280 ASL ROTATE LOW-ORDER 7 BITS
F47F- C9 C0 2290 CMP #$C0 OF HGR.BITS ONE BIT POSN.
F481- 10 06 2300 BPL .1
F483- A5 1C 2310 LDA HGR.BITS
F485- 49 7F 2320 EOR #$7F
F487- 85 1C 2330 STA HGR.BITS
F489- 60 2340 .1 RTS
2350 *--------------------------------
2360 * MOVE RIGHT ONE PIXEL
2370 * IF ALREADY AT RIGHT EDGE, WRAP AROUND
2380 *--------------------------------
2390 MOVE.RIGHT
F48A- A5 30 2400 LDA MON.HMASK
F48C- 0A 2410 ASL SHIFTING BYTE LEFT MOVES PIXEL RIGHT
F48D- 49 80 2420 EOR #$80
2430 * ORIGINAL: C0 A0 90 88 84 82 81
2440 * SHIFTED: 80 40 20 10 08 02 01
2450 * EOR #$80: 00 C0 A0 90 88 84 82
F48F- 30 DD 2460 BMI LR.1 FINISHED
F491- A9 81 2470 LDA #$81 NEW MASK VALUE
F493- C8 2480 INY MOVE TO NEXT BYTE RIGHT
F494- C0 28 2490 CPY #40 UNLESS THAT IS TOO FAR
F496- 90 E0 2500 BCC LR.4 NOT TOO FAR
F498- A0 00 2510 LDY #0 TOO FAR, SO WRAP AROUND
F49A- B0 DC 2520 BCS LR.4 ...ALWAYS
2530 *--------------------------------
S.F1D5