ORG 0100H

EVAR            MACRO @EXVAR,@VAL
                LD BC,256+@EXVAR
                LD D,@VAL
                EXOS 16
                ENDM

X_SIZE          EQU 40
Y_SIZE          EQU 27          ;10
VCHAN           EQU 10

                DI
                LD SP,STACK
                EI              ;15

                EVAR 22,1
                EVAR 23,0
                EVAR 24,X_SIZE
                EVAR 25,Y_SIZE  ;20

                LD A,VCHAN
                LD DE,VID
                EXOS 1
                                ;25
                LD A,VCHAN
                LD BC,SEQLEN
                LD DE,SEQ
                EXOS 8
                                ;30
                LD A,VCHAN
                LD BC,256+1
                LD DE,Y_SIZE*256+1
                EXOS 11
                                ;35
                LD A,VCHAN
                LD B,3
                EXOS 11

                PUSH BC         ;40
                POP HL

                LD A,B
                AND 11000000B
                RLCA            ;45
                RLCA
                OR 11111100B
                LD B,A          ;48 B-ben a syegm.

                CP 255          ;50
                JR NZ,SEG254
                LD DE,32768
SEG254          CP 254
                JR NZ,SEG253
                LD DE,49152     ;55
SEG253          CP 253
                JR NZ,SEG252
                LD DE,0
SEG252          CP 252
                JR NZ,SEGPAGE   ;60
                LD DE,16384
SEGPAGE         ADD HL,DE       ;62 HL-ben P2-es cim

                LD DE,X_SIZE*2*Y_SIZE*9-1
                ADD HL,DE       ;65

                IN A,(0B3H)
                PUSH AF
                IN A,(0B2H)
                PUSH AF         ;70
                IN A,(0B1H)     ;71 mentes
                PUSH AF
                LD A,B          ;73 B-ben A szegm. volt
                OUT (0B1H),A
                INC A           ;75
                OUT (0B2H),A
                INC A
                OUT (0B3H),A

                LD B,200        ;80
CYCL_0          PUSH BC
                PUSH HL

                LD B,Y_SIZE*9
CYCL_1          OR A            ;85
                LD C,X_SIZE*2
CYCL_2          RL (HL)
                DEC HL
                DEC C
                JR NZ,CYCL_2    ;90
                CALL C,R_SIDE
POINT           DJNZ CYCL_1
                JR CEND

R_SIDE          LD DE,X_SIZE*2  ;95
                ADD HL,DE
                SET 0,(HL)
                OR A
                SBC HL,DE
                RET             ;100

CEND            POP HL
                POP BC
                DJNZ CYCL_0
                                ;105
                POP AF
                OUT (0B1H),A
                POP AF
                OUT (0B2H),A
                POP AF          ;110
                OUT (0B3H),A

LOOP            JR LOOP

VID     DB 6                    ;115
                DEFM "VIDEO:"
SEQ             DB 27,"C",255,32,32,255,0,0,0,0
                DB 27,"A"
                DW 640,486
                DB 27,"E"       ;120
                DW 480,480
                DB 27,"F"
SEQLEN          EQU $-SEQ
                DEFS 64
STACK           DEFB 0
                END