;*********************************************************************** ; ; MicroChess (c) 1976 Peter Jennings, peterj@benlo.com ; ;*********************************************************************** ; ; Sources: ; http://www.benlo.com - personal page of P.Jennings ; http://www.6502.org/source/games/uchess/uchess.htm - source by Daryl Rictor ; http://www.benlo.com/microchess/Kim-1Microchess.html - detailed ASM documentation ; *=$0800 ; Loading address of all block JMP BEGIN ; Good to start right from the beginning banner = * ; current address .byte "MicroChess (c) 1976 by Peter Jennings, " .byte "RS-232 for PC by Daryl Rictor, 2002 ", $00 ; ; page zero variables ; These are actual addresses, it's important BOARD = $0850 BK = $0860 PIECE = $08B0 SQUARE = $08B1 SP2 = $08B2 SP1 = $08B3 INCHEK = $08B4 STATE = $08B5 MOVEN = $08B6 REV = $08B7 OMOVE = $08DC WCAP0 = $08DD COUNT = $08DE BCAP2 = $08DE WCAP2 = $08DF BCAP1 = $08E0 WCAP1 = $08E1 BCAP0 = $08E2 MOB = $08E3 MAXC = $08E4 CC = $08E5 PCAP = $08E6 BMOB = $08E3 BMAXC = $08E4 BMCC = $08E5 ; was BCC (TASS doesn't like it as a label) BMAXP = $08E6 XMAXC = $08E8 WMOB = $08EB WMAXC = $08EC WCC = $08ED WMAXP = $08EE PMOB = $08EF PMAXC = $08F0 PCC = $08F1 PCP = $08F2 OLDKY = $08F3 BESTP = $08FB BESTV = $08FA BESTM = $08F9 DIS1 = $08FB DIS2 = $08FA DIS3 = $08F9 INPKEY = $08FC ; Input at address... Javascript modifies this byte... *=$0850 ; To let insert empty bytes...(javascript does) *=$0900 ; BLOCK DATA SETW = * .byte $03, $04, $00, $07, $02, $05, $01, $06 .byte $10, $17, $11, $16, $12, $15, $14, $13 .byte $73, $74, $70, $77, $72, $75, $71, $76 .byte $60, $67, $61, $66, $62, $65, $64, $63 MOVEX = * .byte $00, $F0, $FF, $01, $10, $11, $0F, $EF, $F1 .byte $DF, $E1, $EE, $F2, $12, $0E, $1F, $21 POINTS = * .byte $0B, $0A, $06, $06, $04, $04, $04, $04 .byte $02, $02, $02, $02, $02, $02, $02, $02 OPNING = * .byte $99, $25, $0B, $25, $01, $00, $33, $25 .byte $07, $36, $34, $0D, $34, $34, $0E, $52 .byte $25, $0D, $45, $35, $04, $55, $22, $06 .byte $43, $33, $0F, $CC ; THE PROGRAM STARTS HERE... ; BEGIN LDA #$00 ; CLD ; INITIALIZE LDX #$FF ; TWO STACKS TXS LDX #$C8 STX SP2 ; ; ROUTINES TO LIGHT LED ; DISPLAY AND GET KEY ; FROM KEYBOARD ; INOUT LDA INPKEY PHA LDA #$00 ; CLEAR INPUT STA INPKEY PLA ; CMP #$43 ; [C] BNE NOSET ; SET UP LDX #$1F ; BOARD WHSET LDA SETW,X ; FROM STA BOARD,X ; SETW DEX BPL WHSET LDX #$1B ; *ADDED STX OMOVE ; INITS TO $FF LDA #$CC ; Display CCC BNE CLDSP ; NOSET CMP #$45 ; [E] BNE NOREV ; REVERSE JSR REVERSE ; BOARD IS SEC LDA #$01 SBC REV STA REV ; TOGGLE REV FLAG LDA #$EE ; IS BNE CLDSP ; NOREV CMP #$40 ; [P] BNE NOGO ; PLAY CHESS JSR GO CLDSP STA DIS1 ; DISPLAY STA DIS2 ; ACROSS STA DIS3 ; DISPLAY JMP exitprog ; NOGO CMP #$0D ; [Enter] BNE NOMV ; MOVE MAN JSR MOVE ; AS ENTERED JMP DISP NOMV CMP #$41 ; [Q] ***Added to allow game exit*** BEQ DONE ; quit the game, exit back to system. JMP INPUT ; process move DONE JMP exitprog ; exit ; ; THE ROUTINE JANUS DIRECTS THE ; ANALYSIS BY DETERMINING WHAT ; SHOULD OCCUR AFTER EACH MOVE ; GENERATED BY GNM ; ; ; JANUS LDX STATE BMI NOCOUNT ; ; THIS ROUTINE COUNTS OCCURRENCES ; IT DEPENDS UPON STATE TO INDEX ; THE CORRECT COUNTERS ; COUNTS LDA PIECE BEQ OVER ; IF STATE=8 CPX #$08 ; DO NOT COUNT BNE OVER ; BLK MAX CAP CMP BMAXP ; MOVES FOR BEQ XRT ; WHITE ; OVER INC MOB,X ; MOBILITY CMP #$01 ; + QUEEN BNE NOQ ; FOR TWO INC MOB,X ; NOQ BVC NOCAP LDY #$0F ; CALCULATE LDA SQUARE ; POINTS ELOOP CMP BK,Y ; CAPTURED BEQ FOUN ; BY THIS DEY ; MOVE BPL ELOOP FOUN LDA POINTS,Y CMP MAXC,X BCC LESS ; SAVE IF PHP PHA ; TYA ; STY alternative STA PCAP,X ; Emulator specific PLA ; PLP ; STA MAXC,X ; STATE ; LESS CLC PHP ; ADD TO ADC CC,X ; CAPTURE STA CC,X ; COUNTS PLP ; NOCAP CPX #$04 BEQ ON4 BMI TREE ;(=00 ONLY) XRT RTS ; ; GENERATE FURTHER MOVES FOR COUNT ; AND ANALYSIS ; ON4 LDA XMAXC ; SAVE ACTUAL STA WCAP0 ; CAPTURE LDA #$00 ; STATE=0 STA STATE JSR MOVE ; GENERATE JSR REVERSE ; IMMEDIATE JSR GNMZ ; REPLY MOVES JSR REVERSE ; LDA #$08 ; STATE=8 STA STATE ; GENERATE ; JSR OHM ; CONTINUATION JSR UMOVE ; MOVES ; JMP STRATGY ; FINAL EVALUATION NOCOUNT CPX #$F9 BNE TREE ; ; DETERMINE IF THE KING CAN BE ; TAKEN, USED BY CHKCHK ; LDA BK ; IS KING CMP SQUARE ; IN CHECK? BNE RETJ ; SET INCHEK=0 LDA #$00 ; IF IT IS STA INCHEK RETJ RTS ; ; IF A PIECE HAS BEEN CAPTURED BY ; A TRIAL MOVE, GENERATE REPLIES & ; EVALUATE THE EXCHANGE GAIN/LOSS ; TREE BVC RETJ ; NO CAP LDY #$07 ; (PIECES) LDA SQUARE LOOPX CMP BK,Y BEQ FOUNX DEY BEQ RETJ ; (KING) BPL LOOPX ; SAVE FOUNX LDA POINTS,Y ; BEST CAP CMP BCAP0,X ; AT THIS BCC NOMAX ; LEVEL STA BCAP0,X NOMAX DEC STATE LDA #$FB ; IF STATE=FB CMP STATE ; TIME TO TURN BEQ UPTREE ; AROUND JSR GENRM ; GENERATE FURTHER UPTREE INC STATE ; CAPTURES RTS ; ; THE PLAYER'S MOVE IS INPUT ; INPUT CMP #$08 ; NOT A LEGAL BCS ERROR ; SQUARE # JSR DISMV DISP LDX #$1F SEARCH LDA BOARD,X CMP DIS2 BEQ HERE ; DISPLAY DEX ; PIECE AT BPL SEARCH ; FROM HERE STX DIS1 ; SQUARE STX PIECE ERROR JMP exitprog ; ; GENERATE ALL MOVES FOR ONE ; SIDE, CALL JANUS AFTER EACH ; ONE FOR NEXT STE? ; ; GNMZ LDX #$10 ; CLEAR GNMX LDA #$00 ; COUNTERS CLEAR STA COUNT,X DEX BPL CLEAR ; GNM LDA #$10 ; SET UP STA PIECE ; PIECE NEWP DEC PIECE ; NEW PIECE BPL NEX ; ALL DONE? RTS ; #NAME? ; NEX JSR RESET ; READY LDY PIECE ; GET PIECE LDX #$08 STX MOVEN ; COMMON START CPY #$08 ; WHAT IS IT? BPL PAWN ; PAWN CPY #$06 BPL KNIGHT ; KNIGHT CPY #$04 BPL BISHOP ; BISHOP CPY #$01 BEQ QUEEN ; QUEEN BPL ROOK ; ROOK ; KING JSR SNGMV ; MUST BE KING! BNE KING ; MOVES BEQ NEWP ; 8 TO 1 QUEEN JSR LINE BNE QUEEN ; MOVES BEQ NEWP ; 8 TO 1 ; ROOK LDX #$04 STX MOVEN ; MOVES AGNR JSR LINE ; 4 TO 1 BNE AGNR BEQ NEWP ; BISHOP JSR LINE LDA MOVEN ; MOVES CMP #$04 ; 8 TO 5 BNE BISHOP BEQ NEWP ; KNIGHT LDX #$10 STX MOVEN ; MOVES AGNN JSR SNGMV ; 16 TO 9 LDA MOVEN CMP #$08 BNE AGNN BEQ NEWP ; PAWN LDX #$06 STX MOVEN P1 JSR CMOVE ; RIGHT CAP? BVC P2 BMI P2 JSR JANUS ; YES P2 JSR RESET DEC MOVEN ; LEFT CAP? LDA MOVEN CMP #$05 BEQ P1 P3 JSR CMOVE ; AHEAD BVS NEWP ; ILLEGAL BMI NEWP JSR JANUS LDA SQUARE ; GETS TO AND #$F0 ; 3RD RANK? CMP #$20 BEQ P3 ; DO DOUBLE JMP NEWP ; ; CALCULATE SINGLE STEP MOVES ; FOR K,N ; SNGMV JSR CMOVE ; CALC MOVE BMI ILL1 ; -IF LEGAL JSR JANUS ; -EVALUATE ILL1 JSR RESET DEC MOVEN RTS ; ; CALCULATE ALL MOVES DOWN A ; STRAIGHT LINE FOR Q,B,R ; LINE JSR CMOVE ; CALC MOVE BCC OVL ; NO CHK BVC LINE ; NOCAP OVL BMI ILL ; RETURN PHP JSR JANUS ; EVALUATE POSN PLP BVC LINE ; NOT A CAP ILL JSR RESET ; LINE STOPPED DEC MOVEN ; NEXT DIR RTS ; ; EXCHANGE SIDES FOR REPLY ; ANALYSIS ; REVERSE LDX #$0F ETC SEC LDY BK,X ; SUBTRACT LDA #$77 ; POSITION SBC BOARD,X ; FROM 77 STA BK,X PHP PHA ; STY BOARD,X TYA ; alternative STA BOARD,X ; Emulator specific PLA ; PLP SEC LDA #$77 ; EXCHANGE SBC BOARD,X ; PIECES STA BOARD,X DEX BPL ETC RTS ; ; CMOVE CALCULATES THE TO SQUARE ; USING SQUARE AND THE MOVE ; TABLE FLAGS SET AS FOLLOWS: ; N#NAME? MOVE ; V#NAME? (LEGAL UNLESS IN CR) ; C#NAME? BECAUSE OF CHECK ; [MY &THANKS TO JIM BUTTERFIELD ; WHO WROTE THIS MORE EFFICIENT ; VERSION OF CMOVE) ; CMOVE LDA SQUARE ; GET SQUARE LDX MOVEN ; MOVE POINTER CLC ADC MOVEX,X ; MOVE LIST STA SQUARE ; NEW POS'N AND #$88 BNE ILLEGAL ; OFF BOARD LDA SQUARE ; LDX #$20 LOOP DEX ; IS TO BMI NO ; SQUARE CMP BOARD,X ; OCCUPIED? BNE LOOP ; CPX #$10 ; BY SELF? BMI ILLEGAL ; LDA #$FF ; MUST BE CAP! ORIGINALLY $7F, emulator doesnt set overflow flag ADC #$01 ; SET V FLAG BVS SPX ; (JMP) ; NO CLV ; NO CAPTURE ; SPX LDA STATE ; SHOULD WE BMI RETL ; DO THE CMP #$08 ; CHECK CHECK? BPL RETL ; ; CHKCHK REVERSES SIDES ; AND LOOKS FOR A KING ; CAPTURE TO INDICATE ; ILLEGAL MOVE BECAUSE OF ; CHECK SINCE THIS IS ; TIME CONSUMING, IT IS NOT ; ALWAYS DONE ; CHKCHK PHA ; STATE #392 PHP LDA #$F9 STA STATE ; GENERATE STA INCHEK ; ALL REPLY JSR MOVE ; MOVES TO JSR REVERSE ; SEE IF KING JSR GNM ; IS IN JSR RUM ; CHECK PLP PLA STA STATE LDA INCHEK BMI RETL ; NO - SAFE SEC ; YES - IN CHK LDA #$FF RTS ; RETL CLC ; LEGAL LDA #$00 ; RETURN RTS ; ILLEGAL LDA #$FF CLC ; ILLEGAL CLV ; RETURN RTS ; ; REPLACE PIECE ON CORRECT SQUARE ; RESET LDX PIECE ; GET LOGAT LDA BOARD,X ; FOR PIECE STA SQUARE ; FROM BOARD RTS ; ; ; GENRM JSR MOVE ; MAKE MOVE GENR2 JSR REVERSE ; REVERSE BOARD JSR GNM ; GENERATE MOVES RUM JSR REVERSE ; REVERSE BACK ; ; ROUTINE TO UNMAKE A MOVE MADE BY ; MOVE ; UMOVE TSX ; UNMAKE MOVE STX SP1 LDX SP2 ; EXCHANGE TXS ; STACKS PLA ; MOVEN STA MOVEN PLA ; CAPTURED STA PIECE ; PIECE TAX PLA ; FROM SQUARE STA BOARD,X PLA ; PIECE TAX PLA ; TO SOUARE STA SQUARE STA BOARD,X JMP STRV ; ; THIS ROUTINE MOVES PIECE ; TO SQUARE, PARAMETERS ; ARE SAVED IN A STACK TO UNMAKE ; THE MOVE LATER ; MOVE TSX STX SP1 ; SWITCH LDX SP2 ; STACKS TXS LDA SQUARE PHA ; TO SQUARE TAY LDX #$1F CHECK CMP BOARD,X ; CHECK FOR BEQ TAKE ; CAPTURE DEX BPL CHECK TAKE LDA #$CC STA BOARD,X TXA ; CAPTURED PHA ; PIECE LDX PIECE LDA BOARD,X PHP ; FROM PHA ; STY BOARD,X TYA ; alternative STA BOARD,X ; Emulator specific PLA ; PLP PHA ; SQUARE TXA PHA ; PIECE LDA MOVEN PHA ; MOVEN STRV TSX STX SP2 ; SWITCH LDX SP1 ; STACKS TXS ; BACK RTS ; ; CONTINUATION OF SUB STRATGY ; -CHECKS FOR CHECK OR CHECKMATE ; AND ASSIGNS VALUE TO MOVE ; CKMATE LDY BMAXC ; CAN BLK CAP CPX POINTS ; MY KING? BNE NOCHEK LDA #$00 ; GULP! BEQ RETV ; DUMB MOVE! ; NOCHEK LDX BMOB ; IS BLACK BNE RETV ; UNABLE TO LDX WMAXP ; MOVE AND BNE RETV ; KING IN CH? LDA #$FF ; YES! MATE ; RETV LDX #$04 ; RESTORE STX STATE ; STATE=4 ; ; THE VALUE OF THE MOVE (IN ACCU) ; IS COMPARED TO THE BEST MOVE AND ; REPLACES IT IF IT IS BETTER ; PUSH CMP BESTV ; IS THIS BEST BCC RETP ; MOVE SO FAR? BEQ RETP STA BESTV ; YES! LDA PIECE ; SAVE IT STA BESTP LDA SQUARE STA BESTM ; FLASH DISPLAY RETP RTS ; print; actually do nothing & return ; ; MAIN PROGRAM TO PLAY CHESS ; PLAY FROM OPENING OR THINK ; GO LDX OMOVE ; OPENING? BMI NOOPEN ; -NO *ADD CHANGE FROM BPL LDA DIS3 ; -YES WAS CMP OPNING,X ; OPPONENT'S BNE END ; MOVE OK? DEX LDA OPNING,X ; GET NEXT STA DIS1 ; CANNED DEX ; OPENING MOVE LDA OPNING,X STA DIS3 ; DISPLAY IT DEX STX OMOVE ; MOVE IT BNE MV2 ; (JMP) ; END LDA #$FF ; *ADD - STOP CANNED MOVES STA OMOVE ; FLAG OPENING NOOPEN LDX #$0C ; FINISHED STX STATE ; STATE=C STX BESTV ; CLEAR BESTV LDX #$14 ; GENERATE P JSR GNMX ; MOVES ; LDX #$04 ; STATE=4 STX STATE ; GENERATE AND JSR GNMZ ; TEST AVAILABLE ; ; MOVES ; LDX BESTV ; GET BEST MOVE CPX #$0F ; IF NONE BCC MATE ; OH OH! ; MV2 LDX BESTP ; MOVE LDA BOARD,X ; THE STA BESTV ; BEST STX PIECE ; MOVE LDA BESTM STA SQUARE ; AND DISPLAY JSR MOVE ; IT JMP exitprog ; MATE LDA #$FF ; RESIGN RTS ; OR STALEMATE ; ; SUBROUTINE TO ENTER THE ; PLAYER'S MOVE ; DISMV LDX #$04 ; ROTATE DROL ASL DIS3 ; KEY ROL DIS2 ; INTO DEX ; DISPLAY BNE DROL ; ORA DIS3 STA DIS3 STA SQUARE RTS ; ; THE FOLLOWING SUBROUTINE ASSIGNS ; A VALUE TO THE MOVE UNDER ; CONSIDERATION AND RETURNS IT IN ; THE ACCUMULATOR ; STRATGY CLC LDA #$80 ADC WMOB ; PARAMETERS ADC WMAXC ; WITH WHEIGHT ADC WCC ; OF O25 ADC WCAP1 ADC WCAP2 SEC SBC PMAXC SBC PCC SBC BCAP0 SBC BCAP1 SBC BCAP2 SBC PMOB SBC BMOB BCS POS ; UNDERFLOW LDA #$00 ; PREVENTION POS LSR A CLC ; ************** ADC #$40 ADC WMAXC ; PARAMETERS ADC WCC ; WITH WEIGHT SEC ; OF 05 SBC BMAXC LSR A ; ************** CLC ADC #$90 ADC WCAP0 ; PARAMETERS ADC WCAP0 ; WITH WEIGHT ADC WCAP0 ; OF 10 ADC WCAP0 ADC WCAP1 SEC ; [UNDER OR OVER- SBC BMAXC ; FLOW MAY OCCUR SBC BMAXC ; FROM THIS SBC BMCC ; SECTION] SBC BMCC SBC BCAP1 LDX SQUARE ; *************** CPX #$33 BEQ POSN ; POSITION CPX #$34 ; BONUS FOR BEQ POSN ; MOVE TO CPX #$22 ; CENTRE BEQ POSN ; OR CPX #$25 ; OUT OF BEQ POSN ; BACK RANK LDX PIECE BEQ NOPOSN LDY BOARD,X CPY #$10 BPL NOPOSN POSN CLC ADC #$02 NOPOSN JMP CKMATE ; CONTINUE exitprog LDA #$50 ; indicate to javascript STA STATE ; that process is over JMP $FFFF ; break and stop the emulator ; ; ; end of file ; ; This version is for http://e-tradition.net/bytes/6502/assembler.html ; javascript based 6502 emulator.