langsmoke/ref_6502

		*=$1000
		LDA     #$00
		STA     REV
        JSR     Init_6551
CHESS	CLD
		LDX	#$FF
		TXS
		LDX	#$C8
		STX	SP2
OUT		JSR	pout
		JSR	KIN
		CMP	#$43
		BNE	NOSET
		LDX	#$1F
WHSET		LDA	SETW,X
		STA	BOARD,X
		DEX
		BPL	WHSET
		LDX	#$1B
		STX	OMOVE
		LDA	#$CC
		BNE	CLDSP
NOSET		CMP	#$45
		BNE	NOREV
		JSR	REVERSE
		SEC
		LDA	#$01
		SBC	REV
		STA	REV
		LDA	#$EE
		BNE	CLDSP
NOREV		CMP	#$40
		BNE	NOGO
		JSR	GO
CLDSP		STA	DIS1
		STA	DIS2
		STA	DIS3
		BNE	CHESS
NOGO		CMP	#$0D
		BNE	NOMV
		JSR	MOVE
		JMP	DISP
NOMV		CMP     #$41
		BEQ     DONE
		JMP	INPUT
DONE		JMP     $FF00

JANUS		LDX	STATE
		BMI	NOCOUNT
COUNTS		LDA	PIECE
		BEQ	OVER
		CPX 	#$08
		BNE	OVER
		CMP	BMAXP
		BEQ	XRT
OVER		INC	MOB,X
		CMP 	#$01
		BNE	NOQ
		INC	MOB,X
NOQ		BVC	NOCAP
		LDY	#$0F
		LDA	SQUARE
ELOOP		CMP	BK,Y
		BEQ	FOUN
		DEY
		BPL	ELOOP
FOUN		LDA	POINTS,Y
		CMP	MAXC,X
		BCC	LESS
		STY	PCAP,X
		STA	MAXC,X
LESS		CLC
		PHP
		ADC	CC,X
		STA	CC,X
		PLP
NOCAP		CPX	#$04
		BEQ	ON4
		BMI	TREE
XRT		RTS
ON4		LDA	XMAXC
		STA	WCAP0
		LDA	#$00
		STA	STATE
		JSR	MOVE
		JSR	REVERSE
		JSR	GNMZ
		JSR	REVERSE
		LDA	#$08
		STA	STATE
		JSR	UMOVE
		JMP	STRATGY
NOCOUNT	CPX	#$F9
		BNE	TREE
		LDA	BK
		CMP	SQUARE
		BNE	RETJ
		LDA	#$00
		STA	INCHEK
RETJ		RTS
TREE		BVC	RETJ
		LDY	#$07
		LDA	SQUARE
LOOPX		CMP	BK,Y
		BEQ	FOUNX
		DEY
		BEQ	RETJ
		BPL	LOOPX
FOUNX		LDA	POINTS,Y
		CMP	BCAP0,X
		BCC	NOMAX
		STA	BCAP0,X
NOMAX		DEC	STATE
		LDA	#$FB
		CMP	STATE
		BEQ	UPTREE
		JSR	GENRM
UPTREE		INC	STATE
		RTS
INPUT		CMP	#$08
		BCS	ERROR
		JSR	DISMV
DISP		LDX	#$1F
SEARCH		LDA	BOARD,X
		CMP	DIS2
		BEQ	HERE
		DEX
		BPL	SEARCH
HERE		STX	DIS1
		STX	PIECE
ERROR		JMP	CHESS
GNMZ		LDX	#$10
GNMX		LDA	#$00
CLEAR		STA	COUNT,X
		DEX
		BPL	CLEAR
GNM		LDA	#$10
		STA	PIECE
NEWP		DEC	PIECE
		BPL	NEX
		RTS
NEX		JSR	RESET
		LDY	PIECE
		LDX	#$08
		STX	MOVEN
		CPY	#$08
		BPL	PAWN
		CPY	#$06
		BPL	KNIGHT
		CPY	#$04
		BPL	BISHOP
		CPY	#$01
		BEQ	QUEEN
		BPL	ROOK
KING		JSR	SNGMV
		BNE	KING
		BEQ	NEWP
QUEEN		JSR	LINE
		BNE	QUEEN
		BEQ	NEWP
ROOK		LDX	#$04
		STX	MOVEN
AGNR		JSR	LINE
		BNE	AGNR
		BEQ	NEWP
BISHOP		JSR	LINE
		LDA	MOVEN
		CMP	#$04
		BNE	BISHOP
		BEQ	NEWP
KNIGHT		LDX	#$10
		STX	MOVEN
AGNN		JSR	SNGMV
		LDA	MOVEN
		CMP	#$08
		BNE	AGNN
		BEQ	NEWP
PAWN		LDX	#$06
		STX	MOVEN
P1		JSR	CMOVE
		BVC	P2
		BMI	P2
		JSR	JANUS
P2		JSR	RESET
		DEC	MOVEN
		LDA	MOVEN
		CMP	#$05
		BEQ	P1
P3		JSR	CMOVE
		BVS	NEWP
		BMI	NEWP
		JSR	JANUS
		LDA	SQUARE
		AND	#$F0
		CMP	#$20
		BEQ	P3
		JMP	NEWP
SNGMV		JSR	CMOVE
		BMI	ILL1
		JSR	JANUS
ILL1		JSR	RESET
		DEC	MOVEN
		RTS
LINE		JSR	CMOVE
		BCC	OVL
		BVC	LINE
OVL		BMI	ILL
		PHP
		JSR	JANUS
		PLP
		BVC	LINE
ILL		JSR	RESET
		DEC	MOVEN
		RTS
REVERSE		LDX	#$0F
ETC		SEC
		LDY	BK,X
		LDA 	#$77
		SBC  	BOARD,X
		STA  	BK,X
		STY  	BOARD,X
		SEC
		LDA	#$77
		SBC 	BOARD,X
		STA  	BOARD,X
		DEX
		BPL   	ETC
		RTS

CMOVE		LDA	SQUARE
		LDX	MOVEN
		CLC
		ADC	MOVEX,X
		STA	SQUARE
		AND	#$88
		BNE	ILLEGAL
		LDA	SQUARE
		LDX	#$20
LOOP		DEX
		BMI	NO
		CMP  	BOARD,X
		BNE   	LOOP
		CPX	#$10
		BMI   	ILLEGAL
		LDA	#$7F
		ADC	#$01
		BVS   	SPX
NO		CLV
SPX		LDA  	STATE
		BMI   	RETL
		CMP	#$08
		BPL  	RETL

CHKCHK	PHA
		PHP
		LDA	#$F9
		STA	STATE
		STA	INCHEK
		JSR	MOVE
		JSR	REVERSE
		JSR	GNM
		JSR	RUM
		PLP
		PLA
		STA	STATE
		LDA	INCHEK
		BMI	RETL
		SEC
		LDA	#$FF
		RTS
RETL		CLC
		LDA	#$00
		RTS
ILLEGAL	LDA	#$FF
		CLC
		CLV
		RTS
RESET		LDX	PIECE
		LDA	BOARD,X
		STA	SQUARE
		RTS
GENRM		JSR	MOVE
GENR2		JSR	REVERSE
		JSR	GNM
RUM		JSR	REVERSE
UMOVE		TSX
		STX	SP1
		LDX	SP2
		TXS
		PLA
		STA	MOVEN
		PLA
		STA	PIECE
		TAX
		PLA
		STA	BOARD,X
		PLA
		TAX
		PLA
		STA	SQUARE
		STA	BOARD,X
		JMP	STRV
MOVE		TSX
		STX	SP1
		LDX	SP2
		TXS
		LDA	SQUARE
		PHA
		TAY
		LDX	#$1F
CHECK		CMP	BOARD,X
		BEQ	TAKE
		DEX
		BPL	CHECK
TAKE		LDA	#$CC
		STA	BOARD,X
		TXA
		PHA
		LDX	PIECE
		LDA	BOARD,X
		STY	BOARD,X
		PHA
		TXA
		PHA
		LDA	MOVEN
		PHA
STRV		TSX
		STX	SP2
		LDX	SP1
		TXS
		RTS
CKMATE	LDY	BMAXC
		CPX	POINTS
		BNE	NOCHEK
		LDA	#$00
		BEQ	RETV
NOCHEK	LDX	BMOB
		BNE	RETV
		LDX	WMAXP
		BNE	RETV
		LDA	#$FF
RETV		LDX	#$04
		STX	STATE
PUSH		CMP	BESTV
		BCC	RETP
		BEQ	RETP
		STA	BESTV
		LDA	PIECE
		STA	BESTP
		LDA	SQUARE
		STA	BESTM
RETP		LDA	#"."
		Jmp	syschout
GO		LDX	OMOVE
		BMI	NOOPEN
		LDA	DIS3
		CMP	OPNING,X
		BNE	END
		DEX
		LDA	OPNING,X
		STA	DIS1
		DEX
		LDA	OPNING,X
		STA	DIS3
		DEX
		STX	OMOVE
		BNE	MV2
END		LDA     #$FF
		STA	OMOVE
NOOPEN	LDX	#$0C
		STX	STATE
		STX	BESTV
		LDX	#$14
		JSR	GNMX
		LDX	#$04
		STX	STATE
		JSR	GNMZ
		LDX	BESTV
		CPX	#$0F
		BCC	MATE
MV2		LDX	BESTP
		LDA	BOARD,X
		STA	BESTV
		STX	PIECE
		LDA	BESTM
		STA	SQUARE
		JSR	MOVE
		JMP	CHESS
MATE		LDA	#$FF
		RTS
DISMV		LDX	#$04
DROL		ASL	DIS3
		ROL	DIS2
		DEX
		BNE	DROL
		ORA	DIS3
		STA	DIS3
		STA	SQUARE
		RTS
STRATGY	CLC
		LDA	#$80
		ADC	WMOB
		ADC	WMAXC
		ADC	WCC
		ADC	WCAP1
		ADC	WCAP2
		SEC
		SBC	PMAXC
		SBC	PCC
		SBC	BCAP0
		SBC	BCAP1
		SBC	BCAP2
		SBC	PMOB
		SBC	BMOB
		BCS	POS
		LDA	#$00
POS		LSR
		CLC
		ADC	#$40
		ADC	WMAXC
		ADC	WCC
		SEC
		SBC	BMAXC
		LSR
		CLC
		ADC	#$90
		ADC	WCAP0
		ADC	WCAP0
		ADC	WCAP0
		ADC	WCAP0
		ADC	WCAP1
		SEC
		SBC	BMAXC
		SBC	BMAXC
		SBC	BMCC
		SBC	BMCC
		SBC	BCAP1
		LDX	SQUARE
		CPX	#$33
		BEQ	POSN
		CPX	#$34
		BEQ	POSN
		CPX	#$22
		BEQ	POSN
		CPX	#$25
		BEQ	POSN
		LDX	PIECE
		BEQ	NOPOSN
		LDY	BOARD,X
		CPY	#$10
		BPL	NOPOSN
POSN		CLC
		ADC	#$02
NOPOSN	JMP	CKMATE
POUT        	jsr 	pout9
		jsr     pout13
		JSR	POUT10
		LDY   	#$00
		JSR	POUT5
POUT1		lDA   	#"|"
		JSR   	syschout
		LDX   	#$1F
POUT2		TYA
match
            	CMP	BOARD,X
            	BEQ   	POUT4
type
            	DEX
            	BPL	POUT2
		tya
		and	#$01
		sta   	temp
		tya
		lsr
		lsr
		lsr
		lsr
		and   	#$01
		clc
		adc   	temp
square color
		and   	#$01
		bne	pout25
		lda   	#"*"
		.byte	$2c
POUT25		LDA   	#$20
		JSR   	syschout
		JSR   	syschout
POUT3		INY
	        TYA
            	AND   	#$08
            	BEQ   	POUT1
		LDA   	#"|"
		JSR   	syschout
		jsr	pout12
		JSR   	POUT9
            	JSR   	POUT5
		CLC
		TYA
		ADC	#$08
		TAY
		CPY   	#$80
		BEQ   	POUT8
		BNE   	POUT1
POUT4		LDA   	REV
		BEQ   	POUT41
		LDA	cpl+16,X
		BNE	POUT42
POUT41		LDA   	cpl,x
POUT42		JSR	syschout
		lda	cph,x
		jsr   	syschout
		BNE	POUT3
POUT5       	TXA
		PHA
		LDX	#$19
		LDA	#"-"
POUT6		JSR   	syschout
		DEX
		BNE	POUT6
		PLA
		TAX
		JSR	POUT9
		RTS
POUT8		jsr	pout10
		LDA   	$FB
		JSR   	syshexout
        	LDA   	#$20
		JSR   	syschout
        	LDA   	$FA
		JSR   	syshexout
        	LDA   	#$20
		JSR   	syschout
        	LDA   	$F9
		JSR   	syshexout
POUT9      	LDA   	#$0D
		JSR   	syschout
        	LDA   	#$0A
		JSR   	syschout
                RTS
pout10		ldx   	#$00
POUT11		lda	#$20
		jsr   	syschout
		txa
		jsr	syshexout
		INX
		CPX   	#$08
		BNE	POUT11
		BEQ	POUT9
POUT12		TYA
		and 	#$70
		JSR 	syshexout
		rts
Pout13		ldx   	#$00
Pout14		lda   	banner,x
		beq   	POUT15
		jsr   	syschout
		inx
		bne   	POUT14
POUT15		rts
KIN        	LDA   	#"?"
		JSR   	syschout
		JSR   	syskin
            	AND   	#$4F
            	RTS
Init_6551      lda   #$1F
               sta   ACIActl
               lda   #$0B
dtr active low
               sta   ACIAcmd
               rts
syskin         lda   ACIASta
               and   #$08
               beq   syskin
               Lda   ACIAdat
               RTS
syschout       PHA
ACIA_Out1      lda   ACIASta
               and   #$10
               beq   ACIA_Out1
               PLA
               sta   ACIAdat
               RTS
syshexout      PHA
               LSR
               LSR
               LSR
               LSR
               JSR   PrintDig
               PLA
PrintDig       PHY
               AND   #$0F
               TAY
               LDA   Hexdigdata,Y
               PLY
               jmp   syschout
TMP      EQU $6
WEEKDAY:
         CPX #3
         BCS MARCH
         DEY
MARCH    EOR #$7F
         CPY #200
         ADC MTAB-1,X
         STA TMP
         TYA
         JSR MOD7
         SBC TMP
         STA TMP
         TYA
         LSR
         LSR
         CLC
         ADC TMP
MOD7     ADC #7
         BCC MOD7
         RTS
        AST  32
        JSR  SAVE
        PLA
        STA  R15L
        PLA
        STA  R15H
SW16B   JSR  SW16C
        JMP  SW16B
SW16C   INC  R15L
        BNE  SW16D
        INC  R15H
SW16D   LDA  >SET
        PHA
        LDY  $0
        LDA  (R15L),Y
        AND  $F
        ASL
        TAX
        LSR
        EOR  (R15L),Y
        BEQ  TOBR
        STX  R14H
        LSR
        LSR
        LSR
        TAY
        LDA  OPTBL-2,Y
        PHA
        RTS
TOBR    INC  R15L
        BNE  TOBR2
        INC  R15H
TOBR2   LDA  BRTBL,X
        PHA
        LDA  R14H
        LSR
        RTS
RTNZ    PLA
        PLA
        JSR  RESTORE
        JMP  (R15L)
SETZ    LDA  (R15L),Y
        STA  R0H,X
        DEY
        LDA  (R15L),Y
        STA  R0L,X
        TYA
        SEC
        ADC  R15L
        STA  R15L
        BCC  SET2
        INC  R15H
SET2    RTS
OPTBL   DFB  SET-1
BRTBL   DFB  RTN-1
        DFB  LD-1
        DFB  BR-1
        DFB  ST-1
        DFB  BNC-1
        DFB  LDAT-1
        DFB  BC-1
        DFB  STAT-1
        DFB  BP-1
        DFB  LDDAT-1
        DFB  BM-1
        DFB  STDAT-1
        DFB  BZ-1
        DFB  POP-1
        DFB  BNZ-1
        DFB  STPAT-1
        DFB  BM1-1
        DFB  ADD-1
        DFB  BNM1-1
        DFB  SUB-1
        DFB  BK-1
        DFB  POPD-1
        DFB  RS-1
        DFB  CPR-1
        DFB  BS-1
        DFB  INR-1
        DFB  NUL-1
        DFB  DCR-1
        DFB  NUL-1
        DFB  NUL-1
        DFB  NUL-1
SET     BPL  SETZ
LD      LDA  R0L,X
BK      EQU  *-1
        STA  R0L
        LDA  R0H,X
        STA  R0H
        RTS
ST      LDA  R0L
        STA  R0L,X
        LDA  R0H
        STA  R0H,X
        RTS
STAT    LDA  R0L
STAT2   STA  (R0L,X)
        LDY  $0
STAT3   STY  R14H
INR     INC  R0L,X
        BNE  INR2
        INC  R0H,X
INR2    RTS
LDAT    LDA  (R0L,X)
        STA  R0L
        LDY  $0
        STY  R0H
        BEQ  STAT3
POP     LDY  $0
        BEQ  POP2
POPD    JSR  DCR
        LDA  (R0L,X)
        TAY
POP2    JSR  DCR
        LDA  (R0L,X)
        STA  R0L
        STY  R0H
POP3    LDY  $0
        STY  R14H
        RTS
LDDAT   JSR  LDAT
        LDA  (R0L,X)
        STA  R0H
        JMP  INR
STDAT   JSR  STAT
        LDA  R0H
        STA  (R0L,X)
        JMP  INR
STPAT   JSR  DCR
        LDA  R0L
        STA  (R0L,X)
        JMP  POP3
DCR     LDA  R0L,X
        BNE  DCR2
        DEC  R0H,X
DCR2    DEC  R0L,X
        RTS
SUB     LDY  $0
        CPR  SEC
        LDA  R0L
        SBC  R0L,X
        STA  R0L,Y
        LDA  R0H
        SBC  R0H,X
SUB2    STA  R0H,Y
        TYA
        ADC  $0
        STA  R14H
        RTS
ADD     LDA  R0L
        ADC  R0L,X
        STA  R0L
        LDA  R0H
        ADC  R0H,X
        LDY  $0
        BEQ  SUB2
BS      LDA  R15L
        JSR  STAT2
        LDA  R15H
        JSR  STAT2
BR      CLC
BNC     BCS  BNC2
BR1     LDA  (R15L),Y
        BPL  BR2
        DEY
BR2     ADC  R15L
        STA  R15L
        TYA
        ADC  R15H
        STA  R15H
BNC2    RTS
BC      BCS  BR
        RTS
BP      ASL
        TAX
        LDA  R0H,X
        BPL  BR1
        RTS
BM      ASL
        TAX
        LDA  R0H,X
        BMI  BR1
        RTS
BZ      ASL
        TAX
        LDA  R0L,X
        ORA  R0H,X
        BEQ  BR1
        RTS
BNZ     ASL
        TAX
        LDA  R0L,X
        ORA  R0H,X
        BNE  BR1
        RTS
BM1     ASL
        TAX
        LDA  R0L,X
        AND  R0H,X
        EOR  $FF
        BEQ  BR1
        RTS
BNM1    ASL
        TAX
        LDA  R0L,X
        AND  R0H,X
        EOR  $FF
        BNE  BR1
NUL     RTS
RS      LDX  $18
        JSR  DCR
        LDA  (R0L,X)
        STA  R15H
        JSR  DCR
        LDA  (R0L,X)
        STA  R15L
        RTS
RTN     JMP  RTNZ
	  .org $f000
init:
	  lda  #$00
	  sta  mtalock
	  lda  #$40
	  sta  acr
	  lda  #$c0
	  sta  ier
	  ldy  #0
	  lda  #0
stinit:   sta  $100,y
	  iny
	  bne  stinit
	  lda  #$00
	  sta  mtatask
	  ldy  #maxtask-1
initloop:
	  lda  mtasini,y
	  sta  mtastab,y
	  tax
	  lda  #$b0
	  sta  $0104,x
	  tya
	  asl  a
	  tax
	  stx  mtatemp
	  lda  ent_tab,x
	  ldx  mtastab,y
	  sta  $0105,x
	  ldx  mtatemp
	  lda  ent_tab+1,x
	  ldx  mtastab,y
	  sta  $0106,x
	  dey
	  bpl  initloop
	  ldx  #$3f
	  txs
	  lda  #0
	  sta  t1lsl
	  lda  #40
	  sta  t1csh
	  cli
	  jmp  ent_task0
ent_tab:
	  .word ent_task0
	  .word ent_task1
	  .word ent_task2
	  .word ent_task3
mtaentry:
	  php
	  pha
	  txa
	  pha
	  tya
	  pha
	  tsx
	  inc  $105,x
	  bne  mtaent01
	  inc  $106,x
mtaent01:
	  lda  #$00
	  sta  mtalock
	  jmp  mtaswitch
irq:
	  pha
	  txa
	  pha
	  tya
	  pha
	  lda  t1csl
	  lda  #$c0
	  sta  ifr
	  lda  mtalock
	  beq  mtaswitch
	  inc  mtalock
	  jmp  irq_ret
mtaswitch:
	  ldy  mtatask
	  tsx
	  stx  mtastab,y
	  iny
	  cpy  #maxtask
	  bcc  mtanumok
	  ldy  #0
mtanumok:
	  sty  mtatask
	  ldx  mtastab,y
	  txs
irq_ret:
	  pla
	  tay
	  pla
	  tax
	  pla
	  rti
	  .end