; ; CROMEMCO DAZZLER KALEIDOSCOPE ; WRITTEN BY LI-CHEN WANG ; ; REFORMATED AND COMMENTED OCT.2022 H.FRANKE ;------------------------------------------- ; MEMORY STRUCTURE ; 0100..017F PROGRAM ; 0180..01FF STACK (6 BYTES USED) ; 0300..0AFF VIDEO BUFFER 0100 = TOP@ST EQU 100H 0200 = VID@BF EQU 200H ; DAZZLER VIDEO REGISTERS ; ADDRESS REGISTER AT I/O ADDRESS 0EH ; BIT 8 = ON/OFF ; BIT 6..1 = ADDRESS OF VIDEO BUFFER 000E = DAZ@A EQU 0EH ; DAZZLER ADDRESS PORT ADDRESS 0080 = DAZ@ON EQU 80H ; ON/OFF BIT ; MODE REGISTER AT I/O ADDRESS 0FH ; BIT 8 = UNUSED ; BIT 7 = RESOLUTION ; 0 = NORMAL RESOLUTION: 32X32X4 OR 64X64X4 ; 1 = HIGH RESOLUTION: 64X64X1 OR 128X128X1 ; BIT 6 = MEMORY SIZE ; 0 = 512 BYTES ; 1 = 2 KIB ; BIT 5 = COLOUR OR B&W ; 0 = B&W ; 1 = COLOUR ; BIT 4..1 = IBGR OR GREY LEVEL FOR SET PIXEL IN HIGH RESOLUTION (BIT 7 SET) ;[NOWADAYS ONE WOULD COMBINE BIT 7..5 INTO A VIDEO MODE NUMBER LIKE ; 0 (000) = 32 X 32 X 16 GREY LEVEL PER PIXEL ; 1 (001) = 32 X 32 X 16 COLOUR PER PIXEL ; 2 (010) = 64 X 64 X 16 GREY LEVEL PER PIXEL ; 3 (011) = 64 X 64 X 16 COLOUR PER PIXEL ; 4 (100) = 64 X 64 B&W WITH ONE PREDEFINED GREY LEVEL AND BLACK ; 5 (101) = 64 X 64 COLOUR WITH ONE PREDEFINED COLOUR AND BLACK ; 6 (110) = 128 X 128 B&W WITH ONE PREDEFINED GREY LEVEL AND BLACK ; 7 (111) = 128 X 128 COLOUR WITH ONE PREDEFINED COLOUR AND BLACK ;] 000F = DAZ@M EQU 0FH ; DAZZLER ADDRESS PORT ADDRESS 0040 = DAZ@HR EQU 40H ; HIGH RESOLUTION (1) 0020 = DAZ@ML EQU 20H ; MEMORY SIZE 512 BYTES (0) OR 2 KIB (1) 0010 = DAZ@CO EQU 10H ; COLOUR (1) OR B&W (0) ; SYNCHRONISATION REGISTER AT I/O ADDRESS 0EH ;[ADDED FOR COMPLETENESS, NOT USED HERE] ; BIT 8 = EVEN/ODD VIDEO LINE ; BIT 7 = END OF FRAME - SET DURING VERTICAL RETRACE ; BIT 6..1 = UNDEFINED 000E = DAZ@S EQU 0EH ; DAZZLER SYNCHRONIZATION PORT ADDRESS 0040 = DAZ@SL EQU 40H ; LINE SYNCHRONISATION 0040 = DAZ@SF EQU 40H ; FRAME SYNCHRONISATION 0000 ORG 0000H ; PROGRAM START AT RESET ; INITIALIZE STACK 0000 310001 LXI SP,TOP@ST ; SET TOP OF STACK TO 100H ; SWITCH DAZZLER OUTPUT ON AND SET ADDRESS TO 0200H 0003 3E81 MVI A,DAZ@ON+(VID@BF SHR 9) ; ENABLE DAZZLER AND SET THE VIDEO BUFFER START TO 0200H (=081H) 0005 D30E OUT DAZ@A ; SEND TO ADDRESS PORT ; SET DAZZLER VIDEO MODE TO 64X64 @ 16 INDIVIDUAL COLOURS 0007 3E30 MVI A,DAZ@ML+DAZ@CO ; (=30H) 0009 D30F OUT DAZ@M ; SEND TO MODE PORT ; MAIN LOOP HKS: ; REGISTER USAGE DURING MAIN LOOP: ; H = COLOUR, CYCLES FROM 1FH DOWN TO 01H ; EVERY ODD CYCLE USES BLACK ; EVERY EVEN WILL PRODUCE A COLOUR FROM F DOWN TO 1 (BLACK (0) WILL NOT BE REACHED) ; D = MASK (0..FFH) USED TO 'RANDOMIZE' THE NEXT ADDRESS ; E = LOOP COUNTER, COUNTS DOWN FROM 03FH TO 0 ; B = X COORDINATE * 8 ; C = Y COORDINATE * 8 ; NOTE: ; **NO REGISTER IS INITIALIZED PRIOR TO FIRST ITERATION** ; THEY MAY CONTAIN RANDOM VALUES AFTER RESET. ; THIS WILL RESULT IN START AT SOME LOCATION WITH SOME COLOUR. ; GENERATE NEXT 'RANDOM' PIXEL COORDINATE ; NEW Y = LAST Y + ((LAST X >> 2) AND MASK) 000B 78 MOV A,B ; LAST X >> 2 000C 0F RRC 000D 0F RRC 000E A2 ANA D ; AND MASK 000F 81 ADD C ; PLUS LAST Y 0010 4F MOV C,A ; -> NEW Y ; NEW X = LAST X - ((NEW Y >> 2) AND MASK) 0011 0F RRC ; NEW Y >> 2 0012 0F RRC 0013 A2 ANA D ; AND MASK 0014 6F MOV L,A 0015 78 MOV A,B ; LAST X 0016 95 SUB L 0017 47 MOV B,A ; -> NEW X ; START DRAWING 0018 C5 PUSH B ; SAVE REGISTERS TO FREE THEM FOR DATA DURING DRAWING 0019 D5 PUSH D 001A E5 PUSH H 001B 110000 LXI D,0 ; CLEAR COLOUR(S) (SETTING TO BLACK) IN DE 001E 7C MOV A,H ; EXTRACT COLOUR FROM H AND PREPARE TEST FOR DRAW OR CLEAR 001F E61F ANI 01FH 0021 1F RAR ; LOW BIT DEFINES IF BLACK OR OTHER COLOUR IS USED 0022 DA2B00 JC DBLACK ; BIT WAS 0 -> DRAW PIXEL AS BLACK ; IF IT WAS NOT BLACK, COPY THE 4-BIT VALUE INTO E AND D 0025 5F MOV E,A ; COLOUR TO E FOR LOW PIXEL 0026 07 RLC ; SHIFT COLOUR TO HIGH NIBBLE FOR UPPER PIXEL 0027 07 RLC 0028 07 RLC 0029 07 RLC 002A 57 MOV D,A ; DBLACK: ; DRAW A PIXEL MIRRORED 4 TIMES ; ; IN: ; B/C = X/Y 0..31 IN TOP 5 BITS ; D/E = PREPARED COLOUR VALUE ; WORKS OUT QUITE EASY, AS THE DAZZLER MEMORY IN 2KI MODE ; IS ORGANIZED AS 4 PAGES OF 512 BYTES, EACH HOLDING 1/4TH ; OF THE DISPLAY, 32X32 PIXEL IN THE SELECTED MODE. THEY ; ARE POSITIONED AS: ; ; 0200H I 0400H ; PAGE 1 I PAGE 2 ... I ... ; I 03FFH I 05FFH ; --------+-------- -------+------- ; I 0600H I 0800H ; PAGE 3 I PAGE 4 ... I ... ; 07FFH I 09FFH ; ; DUE TO THIS ORGANIZATION IN 4 QUADRANTS IT'S QUITE EASY ; TO MIRROR A PIXEL'S COORDINATES ALONG BOTH AXIS BY SIMPLY ; NEGATING EACH AXIS. ; ; DRAWING IS DONE CLOCKWISE STARTING IN THE LOWER RIGHT QUADRANT ; DRAW PIXEL IN LOWER RIGHT QUADRANT 002B 2608 MVI H,08H ; H = BASE ADDRESS PAGE 4, B/C=X/Y PIXEL WITHIN THAT PAGE 002D CD5D00 CALL OUTPX ; SET PIXEL AT X/Y ; DRAW PIXEL IN LOWER LEFT QUADRANT 0030 78 MOV A,B ; COMPLEMENT B TO FLIP ALONG X AXIS 0031 2F CMA 0032 47 MOV B,A 0033 2606 MVI H,06H ; H = BASE ADDRESS PAGE 3, B/C=X/Y PIXEL WITHIN THAT PAGE 0035 CD5D00 CALL OUTPX ; SET PIXEL AT -X/Y ; DRAW PIXEL IN UPPER LEFT QUADRANT 0038 79 MOV A,C ; COMPLEMENT C TO FLIP ALONG Y AXIS 0039 2F CMA 003A 4F MOV C,A 003B 2602 MVI H,02H ; H = BASE ADDRESS PAGE 1, B/C=X/Y PIXEL WITHIN THAT PAGE 003D CD5D00 CALL OUTPX ; SET PIXEL AT -X/-Y ; DRAW PIXEL IN UPPER RIGHT QUADRANT 0040 78 MOV A,B ; COMPLEMENT B (AGAIN) TO FLIP (BACK) ALONG X AXIS 0041 2F CMA 0042 47 MOV B,A 0043 2604 MVI H,04H ; H = BASE ADDRESS PAGE 2, B/C=X/Y PIXEL WITHIN THAT PAGE 0045 CD5D00 CALL OUTPX ; SET PIXEL AT X/-Y ; DRAWING COMPLETE, MAIN LOOP CONTINUES 0048 E1 POP H ; RESTORE REGISTERS FOR MAIN LOOP 0049 D1 POP D 004A C1 POP B 004B 1D DCR E ; HAVE WE DONE THIS 64 TIMES? 004C C20B00 JNZ HKS ; NO -> BACK TO THE TOP OF THE LOOP ; EVERY 64TH CYCLE, BUMP THE COLORS, LOCATIONS AND MASK TO RANDOMIZE DRAWING 004F 04 INR B ; X = X + 1/8TH 0050 0C INR C ; Y = Y + 1/8TH 0051 1E3F MVI E,03FH ; PREPARE ANOTHER 64 ROUNDS 0053 25 DCR H ; BUT USE THE NEXT COLOUR (1FH..1H) ; LOWEST BIT FLIPS BETWEEN BLACK AND COLOUR 0..F 0054 C20B00 JNZ HKS ; UNLESS BLACK -> DO NEXT ITERATION 0057 14 INR D ; INCREMENT MASK FOR 'RANDOMNESS' 0058 261F MVI H,01FH ; RESTART WITH COLOUR 0FH AGAIN 005A C30B00 JMP HKS ; START OVER ; OUTPUT A PIXEL SUBROUTINE ; IN: ; H HIGH BYTE PAGE BASE (2/4/6/8) ; L --- ; B X COORDINATE WITHIN PAGE (BIT 8..5 -> A3..A0 BIT 4 -> SELECTS HIGH/LOW PIXEL) ; C Y COORDINATE WITHIN PAGE (BIT 8..4 -> A8..A4) ; D PREPARED COLOUR FOR LOW PIXEL (IN BIT 4..1) ; E PREPARED COLOUR FOR HIGH PIXEL (IN BIT 8..5) ; OUT: ; PIXEL SET ; A,H,L DESTROYED ; B,C,D,E UNCHANGED ; STEP ONE: ; TURN 5+5 BIT X/Y ADDRESS INTO 9 BIT ADDRESS ; PLUS HIGH/LOW PIXEL MARKER 005D 79 OUTPX: MOV A,C ; UPPER 5 BITS OF PIXEL ADDRESS 005E E6F8 ANI 0F8H ; EXTRACT UNDER MASK 0060 17 RAL ; MOVE HIGH BIT TO CARRY 0061 6F MOV L,A ; SAVE TO LOW BYTE OF HL POINTER 0062 7C MOV A,H ; GET PAGE BASE 0063 CE00 ACI 00H ; ADD HIGH BIT TO HIGH BYTE OF HL POINTER 0065 67 MOV H,A ; SAVE TO HIGH BYTE OF HL POINTER 0066 78 MOV A,B ; LOWER 5 BIT OF PIXEL ADDRESS 0067 E6F8 ANI 0F8H ; EXTRACT UNDER MASK 0069 1F RAR ; MOVE TOP 4 TO LOWER NIBBLE, LOWEST TO CARRY 006A 1F RAR 006B 1F RAR 006C 1F RAR 006D F5 PUSH PSW ; PRESERVE CARRY FLAG HOLDING THE PIXEL 'ADDRESS' 006E 85 ADD L ; ADD LOWER NIBBLE TO LOW BYTE OF HL POINTER 006F 6F MOV L,A ; SAVE TO LOW BYE OF HL POINTER 0070 F1 POP PSW ; RESTORE CARRY FLAG CONTAINING THE LOWEST PIXEL ADDRESS ; CY=0 LOW PIXEL; CY=1 HIGH PIXEL ; STEP TWO: ; SET HIGH OR LOW PIXEL, ACCORDING TO THE CARRY BIT, TO THE DRAWING COLOUR 0071 7E MOV A,M ; READ EXISTING PIXEL PAIR 0072 DA7A00 JC OUTHPX ; CY SET -> GO DO HIGH PIXEL ; CY CLEARED -> DO LOW PIXEL ; OUTPUT LOW PIXEL 0075 E6F0 ANI 0F0H ; MASK OUT (CLEAR) OLD LOW PIXEL 0077 83 ADD E ; INSERT NEW LOW PIXEL 0078 77 MOV M,A ; STORE IN VIDEO BUFFER 0079 C9 RET ; OUTPUT HIGH PIXEL 007A E60F OUTHPX: ANI 0FH ; MASK OUT (CLEAR) OLD HIGH PIXEL 007C 82 ADD D ; INSERT NEW HIGH PIXEL 007D 77 MOV M,A ; STORE IN VIDEO BUFFER 007E C9 RET 007F END