TITLE * SIMULATOR AY-ZX 

	.Z80
 	ASEG
 	ORG 2000H
; 
; 
;	SEM SE SPADNE MISTO PROVEDENI INSTRUKCE OUT (c),A
;	PRICEMZ BC=0BFFDH	DATA
;		BC=0FFFDH	STATUS
START:	JR SETINT

VECTIN:	DW 0	;VEKTOR PRERUSENI

MUSIC:	LD C,A
	LD A,B
        CP 0FFH
        JR NZ,DATA
        PUSH HL
        PUSH BC
        AND 0FH
        LD C,A
        LD B,0
        LD HL,C31F1
        ADD HL,BC
        LD (MODIF),HL ;	ULOZI STATUS
        POP BC
        POP HL
        RET
        
SETINT:	PUSH HL
	PUSH BC
        DI
        IM 2
        LD,HL,VECTIN
        LD A,H
        LD I,A
        LD A,L
        OUT (0FCH),A
        LD HL,PIOD
        LD BC,04FCH
        OTIR
        
        LD HL,MUSIC	;NASTAV RESTART
        LD(031H),HL
        
        POP BC
        POP HL
        EI
        RETI
        
MODIF	EQU $+1
DATA:	LD (C31F1),A	;MODIFIKUJE TUHLE ADRESU NASTAVI STATUS
	LD (W320D),SP	;ULOZ SP
        LD SP,C322D	;NASTAV SVUJ SP
        LD SP,C322D	;NASTAV SVUJ SP - TAK TADY NEVIM JESTLI TO OPRAVDU
        		;TAK MA BYT NA PAPIRE TO TAM MAM, ALE JE TO BLBOST
	PUSH AF
        PUSH BC
        PUSH DE
        PUSH HL
        PUSH IX		;ULOZ CO JDE
        LD BC,0AH
        LD DE,C3202
        LD HL,C3201	;SMAZ POLE PRO PSG
        LD (HL),B
        LDIR
        LD B,3		;JSOU 3 KANALY
        LD DE,C31F1	;ADRESA FREKVENCE AY
        LD HL,C31F8	;ADRESA MIX
        LD IX,C3201	;ADRESA FREKVENCE SN
        LD C,(HL)	;DO C STAV MIXU
        
;	SMYCKA INICIALIZACE 3 KANALU

L304A:	INC HL		;HLASITOST
	BIT 3,C		;SUM A?
        JR NZ,L3057	;NE
        LD A,(HL)	;HLASITOST SUMU?
        AND 0FH
        JR Z,L3057	;NULOVA
        LD (V320B),A	;JINAK ULOZ HLASITOST SUMU
L3057:	RR C
	JP C,L30DD	;DALSI POKUD KANAL NEZNI
        LD A,(HL)	;HLASITOST KANALU
        AND 0FH		;0-15
        JP Z,L30DD	;VYPNUTY => DALSI
        INC DE
        LD A,(DE)	;VYSSI BAJT FREKVENCE KANALU
        DEC DE		;ZPET NA NIZSI
        AND 0FH		;ZAJIMA NAS POUZE SPODNI PULBAJT
        JR NZ,L306E	;JE NENULOVY
        LD A,(DE)	;SPODNI PULBAJT
        CP 10H
        JR C,L30DD	;SKOC POKUD JE FREKVENCE < XXXX0000 0001000
L306E:	INC DE		
	LD A,(DE)	;PRECTI VYSSI BAJT FREKVENCE
        DEC DE		;ZPET NA NIZSI
        AND 0CH
        JR Z,L309D
        LD A,(V320B)	;PUVODNI HLASITOST SUMU
        OR A
        JR NZ,L309D	;SKOC KDYZ ZNI
        INC DE		;VYSSI A
        LD A,(DE)
        DEC DE
        AND 0FH
        LD (V3208),A	;ULOZ VYSSI C
        LD A,(DE)	;NIZSI A
        RRCA
        RRCA
        RRCA
        RRCA
        AND 0FH
        LD (V3207),A
        LD A,(HL)	;HLASITOST
        SUB 3
        INC A
        JR C,L30DD
        LD (V320B),A	;HLASITOST SUMU
        LD A,0E3H
        LD (V320A),A	;FREKVENCE SUMU
        JR L30DD	;DALSI KANAL
        
L309D:	PUSH BC
	LD A,(DE)	;NIZSI BAJT A KANALU
        LD C,A
        INC DE		;VYSSI
        LD A,(DE)
        DEC DE		;ZPET NA NIZSI
        AND 0FH		;ZAJIMAJI NAS POUZE SPODNI 4 BITY
        LD B,A
        LD A,(HL)	;HLASITOST
        LD (IX+2),A

L30AA:	LD A,0CH
	AND B
        JR Z,L30C7
        LD A,(IX+2)	;MIX
        SUB 4
        INC A
        LD (IX+2),A
        JR NC,L30C1
        LD (IX+2),0
        POP BC
        JR L30DD	;DALSI KANAL
        
L30C1:	SRL B
	RR C
        JR L30AA
        
L30C7:	LD A,C
	ANF 0FH
	LD (IX+0),A
        INC IX
        XOR C
        OR B
        RRCA
        RRCA
        RRCA
        RRCA
        LD (IX+0),A
        INC IX
        INC IX
        POP BC
        
L30DD:	INC DE
	INC DE		;VYSSI BAJT FREKVENCE DALSIHO KANALU
        DEC B		;DALSI KANAL?
        JP NZ,L304A	;ANO ZNOVU

;	TOTO PROBEHNE PO INICIALIZACI VSECH 3 KANALU
	
        LD A,(V320A)
        XOR 0E3H
        JR Z,L30FA
        LD A,(V31F7)
        AND 1FH
        LD D,0
        LD E,A
        LD HL,C3131
        ADD HL,DE
        LD A,(HL)
        LD (V320A),A
L30FA:	LD BC,0380H
	LD HL,C3201
L3100:	LD A,C
	OR (HL),A
        INC HL
        INC HL
        LD A,(HL)
        CPL
        AND 0FH
        LD D,A
        LD A,C
        ADD A,10H
        OR D
        LD (HL),A
        INC HL
        LD A,C
        ADD A,20H
        LD C,A
        DJNZ,L3100
        LD HL,V320B
        LD A,(HL)
        AND 0FH
        CPL
        LD (HL),A
        LD BC,0BF2H
        LD HL,C3201
        OTIR		;SET PSG SHARP
        POP IX
        POP HL
        POP DE
        POP BC
        POP AF
        LD SP,(C3201)
        RET		;VEN DO SPECTRUM PROGRAMU
        
C3131:	DB 0E4H,0E4H,0E4H        
	DB 0E4H,0E4H,0E4H        
	DB 0E4H,0E4H,0E4H        
	DB 0E4H,0E4H,0E4H        
	DB 0E4H,0E4H,0E4H        
	DB 0E4H,0E5H,0E5H
	DB 0E5H,0E5H,0E5H
	DB 0E4H,0E5H,0E5H
	DB 0E6H,0E6H,0E6H,0E6H
        DB 0E6H,0E6H,0E6H,0E6H
        
C31F1:	DB 0		;FREKVENCE A NIZSI 00000000
	DB 0		;FREKVENCE A VYSSI XXXX0000
        DB 0		;FREKVENCE B
        DB 0
        DB 0		;FREKVENCE C
        DB 0
V31F7:	DB 0		;FREKVENCE SUMU 0-0FH
C31F8:	DB 0		;MIX
	DB 0		;HLASITOST A 0-0FH
        DB 0		;HLASITOST B
        DB 0		;HLASITOST C
        DB 0		;MODUL KRIVKA JEMNE
        DB 0		;MODUL KRIVKA HRUBE
        DB 0		;TVAR KRIVKY
        DB 0		;I/O PORT
        DB 0		;I/O PORT
        
;	DATA PRO PSG

C3201:	DB 0          
C3202:	DB 0
	DB 0
        DB 0		
        DB 0
        DB 0	
V3207:	DB 0
V3208:	DB 0
	DB 0
V320A:	DB 0
V320B:	DB 0		;HLASITOST SUMU
W320D:	DS 20H		;MISTO PRO ULOZENI SP
C322D:	DB 0		;PRACOVNI SP
PIOD:	DB 0CFH,03FH,0B7H,0DFH
;	
	END