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Edited CHESS to match the Sargon book listing more

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This commit is contained in:
Yufeng Gao
2026-02-01 00:04:34 +10:00
parent c7b866b40d
commit 8495cf296a
1 changed files with 214 additions and 121 deletions
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CHESS.A86
+214 -121
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@@ -1,13 +1,12 @@
;***********************************************************
;
; SARGON
; SARGON
;
; Sargon is a computer chess playing program designed
; and coded by Dan and Kathe Spracklen. Copyright 1978. All
; rights reserved. No part of this publication may be
; reproduced without the prior written permission.
;***********************************************************
;
;***********************************************************
; SYSTEM EQUATES
;***********************************************************
@@ -15,7 +14,6 @@ INCHAR: EQU 1
PRINTBUF:EQU 9
INBUF: EQU 10
SYSTEM: EQU 5
;***********************************************************
; EQUATES
;***********************************************************
@@ -45,7 +43,7 @@ BPAWN: EQU BLACK+PAWN
; PLYRMV
;
; ARGUMENTS: None
;***********************************************************
;**********************************************************
DRIVER: MOV SP,STACK ; Set stack pointer
MOV DX,CLRMSG ; Request color choice
MOV CL,PRINTBUF
@@ -88,6 +86,8 @@ DR25: CALL CPTRMV ; Do computer move
INC B,[BX] ; Increment move number
JP DR20 ; Back to player move
;***********************************************************
; TABLES SECTION
;***********************************************************
@@ -97,7 +97,7 @@ START:
PUT START+80H
TBASE: EQU START+100H
;***********************************************************
; DIRECT -- Direction Table. Used to determine the dir-
; DIRECT -- Direction Table. Used to determine the dir-
; ection of movement of each piece.
;***********************************************************
DIRECT: EQU $-TBASE
@@ -107,6 +107,9 @@ DIRECT: EQU $-TBASE
DB +21,+12,-08,-19
DB +10,+10,+11,+09
DB -10,-10,-11,-09
;***********************************************************
; DPOINT -- Direction Table Pointer. Used to determine
; where to begin in the direction table for any
@@ -114,7 +117,6 @@ DIRECT: EQU $-TBASE
;***********************************************************
DPOINT: EQU $-TBASE
DB 20,16,8,0,4,0,0
;***********************************************************
; DCOUNT -- Direction Table Counter. Used to determine
; the number of directions of movement for any
@@ -123,13 +125,14 @@ DPOINT: EQU $-TBASE
DCOUNT: EQU $-TBASE
DB 4,4,8,4,4,8,8
;***********************************************************
; PVALUE -- Point Value. Gives the point value of each
; piece, or the worth of each piece.
;***********************************************************
PVALUE: EQU $-TBASE-1
DB 1,3,3,5,9,10
;***********************************************************
; PIECES -- The initial arrangement of the first rank of
; pieces on the board. Use to set up the board
@@ -138,6 +141,8 @@ PVALUE: EQU $-TBASE-1
PIECES: EQU $-TBASE
DB 4,2,3,5,6,3,2,4
;***********************************************************
; BOARD -- Board Array. Used to hold the current position
; of the board during play. The board itself
@@ -159,27 +164,29 @@ PIECES: EQU $-TBASE
; moves off the board. The individual bits of
; the other bytes in the board array are as
; follows:
; Bit 7 -- Color of the piece
; 1 -- Black
; 0 -- White
; Bit 6 -- Not used
; Bit 5 -- Pawn attack flag for ATTACK
; Bit 4 -- Castle flag for Kings only
; Bit 3 -- Piece has moved flag
; Bits 2-0 Piece type
; 1 -- Pawn
; 2 -- Knight
; 3 -- Bishop
; 4 -- Rook
; 5 -- Queen
; 6 -- King
; 7 -- Not used
; 0 -- Empty Square
;***********************************************************
; Bit 7 -- Color of the piece
; 1 -- Black
; 0 -- White
; Bit 6 -- Not used
; Bit 5 -- Pawn attack flag for ATTACK
; Bit 4 -- Castle flag for Kings only
; Bit 3 -- Piece has moved flag
; Bits 2-0 Piece type
; 1 -- Pawn
; 2 -- Knight
; 3 -- Bishop
; 4 -- Rook
; 5 -- Queen
; 6 -- King
; 7 -- Not used
; 0 -- Empty Square
;************************************************************
BOARD: EQU $-TBASE
BOARDA: DS 120
;***********************************************************
;************************************************************
; ATKLIST -- Attack List. A two part array, the first
; half for white and the second half for black.
; It is used to hold the attackers of any given
@@ -196,6 +203,8 @@ ATKLST: DW 0,0,0,0,0,0,0
WACT: EQU ATKLST
BACT: EQU ATKLST+7
;***********************************************************
; PLIST -- Pinned Piece Array. This is a two part array.
; PLISTA contains the pinned piece position.
@@ -206,6 +215,8 @@ PLIST: EQU $-TBASE-1
PLISTD: EQU PLIST+10
PLISTA: DW 0,0,0,0,0,0,0,0,0,0
;***********************************************************
; POSK -- Position of Kings. A two byte area, the first
; byte of which hold the position of the white
@@ -218,13 +229,17 @@ POSK: DB 24,95
POSQ: DB 14,94
DB -1
;************************************************************
; SCORE -- Score Array. Used during Alpha-Beta pruning to
; hold the scores at each ply. It includes two
; "dummy" entries for ply -1 and ply 0.
;************************************************************
SCORE: DW 0,0,0,0,0,0
SCORE: DW 0,0,0,0,0,0
;************************************************************
; PLYIX -- Ply Table. Contains pairs of pointers, a pair
; for each ply. The first pointer points to the
@@ -232,15 +247,19 @@ SCORE: DW 0,0,0,0,0,0
; The second pointer points to which move in the
; list is the one currently being considered.
;************************************************************
PLYIX: DW 0,0,0,0,0,0,0,0,0,0
DW 0,0,0,0,0,0,0,0,0,0
;************************************************************
; STACK -- Contains the stack for the program.
;************************************************************
ORG START+2FFH
STACK:
;************************************************************
; TABLE INDICES SECTION
;
@@ -295,6 +314,8 @@ BESTM: DW 0
MLLST: DW 0
MLNXT: DW MLIST
;************************************************************
; VARIABLES SECTION
;
@@ -381,6 +402,8 @@ BMOVES: DB 35,55,10H
DB 85,65,10H
DB 84,64,10H
;************************************************************
; MOVE LIST SECTION
;
@@ -406,8 +429,8 @@ BMOVES: DB 35,55,10H
; information. The meaning of each bit is as
; follows:
; Bit 7 -- The color of any captured piece
; 0 -- White
; 1 -- Black
; 0 -- White
; 1 -- Black
; Bit 6 -- Double move flag (set for castling and
; en passant pawn captures)
; Bit 5 -- Pawn Promotion flag; set when pawn
@@ -435,6 +458,8 @@ MLTOP: EQU 3
MLFLG: EQU 4
MLVAL: EQU 5
;************************************************************
; PROGRAM CODE SECTION
;************************************************************
@@ -449,6 +474,7 @@ MLVAL: EQU 5
; CALLS: None
;
; ARGUMENTS: None
;
;*************************************************************
INITBD: MOV CX,60 ; Pre-fill board with -1's
MOV DI,BOARDA
@@ -479,6 +505,8 @@ IB2: MOV AL,[SI-8] ; Fill non-border squares
MOV B,[SI+3],94
RET
;************************************************************
; PATH ROUTINE
;************************************************************
@@ -505,10 +533,10 @@ IB2: MOV AL,[SI-8] ; Fill non-border squares
; ARGUMENTS: Direction from the direction array giving the
; constant to be added for the new position.
;************************************************************
PATH: ADD [M2],CL ; Add direction constant to previous position
PATH: ADD [M2],CL ; Add direction constant to prev pos
MOV SI,[M2] ; Load board index
MOV AL,[SI+BOARD] ; Get contents of board
CMP AL,-1 ; In border area ?
CMP AL,-1 ; In boarder area ?
JZ PA2 ; Yes - jump
MOV [P2],AL ; Save piece
MOV AH,AL ; Save piece in register
@@ -521,7 +549,9 @@ PATH: ADD [M2],CL ; Add direction constant to previous position
SBB AL,0
RET ; Return
PA2: MOV AL,3 ; Set off board flag
RET
RET ; Return
;************************************************************
; PIECE MOVER ROUTINE
@@ -611,6 +641,8 @@ MP37: OR B,[P2],020H ; Set promote flag
MP36: CALL ENPSNT ; Try en passant capture
JMP MP15 ; Jump
;***********************************************************
; EN PASSANT ROUTINE
;***********************************************************
@@ -621,6 +653,7 @@ MP36: CALL ENPSNT ; Try en passant capture
; CALLED BY: -- MPIECE
;
; CALLS: -- ADMOVE
; ADJPTR
;
; ARGUMENTS: -- None
@@ -636,7 +669,7 @@ EP5: CMP AL,61 ; On en passant capture rank ?
MOV SI,[MLPTRJ] ; Get pointer to previous move
TEST B,[SI+MLFLG],010H ; First move for that piece ?
JZ RET ; No - return
MOV AL,[SI+MLTOP] ; Get "to" position
MOV AL,[SI+MLTOP] ; Get "to" postion
MOV [M4],AL ; Store as index to board
MOV SI,[M4] ; Load board index
MOV AL,[SI+BOARD] ; Get piece moved
@@ -665,6 +698,8 @@ EP10: CMP AL,10 ; Is difference 10 ?
MOV AL,[M3] ; Restore "from" position
MOV [M1],AL
;************************************************************
; ADJUST MOVE LIST POINTER FOR DOUBLE MOVE
;************************************************************
@@ -686,8 +721,10 @@ ADJPTR: MOV BX,[MLLST] ; Get list pointer
MOV [BX],0 ; Zero out link
RET ; Return
;************************************************************
; CASTLE ROUTINE
;CASTLE ROUTINE
;************************************************************
; FUNCTION: -- To determine whether castling is legal
; (Queen side, King side, or both) and add it
@@ -759,6 +796,8 @@ CA20: MOV AL,CH ; Scan Index
MOV CX,01FCH ; Set Queen-side initial values
JMP CA5 ; Jump
;************************************************************
; ADMOVE ROUTINE
;************************************************************
@@ -800,19 +839,21 @@ AM5: XCHG DX,DI ; Address of move area
AM10: MOV [BX],0 ; Abort entry on table ovflow
RET
;***********************************************************
;************************************************************
; GENERATE MOVE ROUTINE
;***********************************************************
; FUNCTION: -- To generate the move set for all of the
; pieces of a given color.
;************************************************************
; FUNCTION: -- To generate the move set for all of the
; pieces of a given color.
;
; CALLED BY: -- FNDMOV
; CALLED BY: -- FNDMOV
;
; CALLS: -- MPIECE
; INCHK
; CALLS: -- MIECE
; INCHK
;
; ARGUMENTS: -- None
;***********************************************************
; ARGUMENTS: -- None
;************************************************************
GENMOV: CALL INCHK ; Test for King in check
MOV [CKFLG],AL ; Save attack count as flag
MOV DX,[MLNXT] ; Addr of next avail list space
@@ -830,7 +871,7 @@ GM5: MOV [M1],AL ; Save as index
MOV AL,[SI+BOARD] ; Fetch board contents
AND AL,AL ; Is it empty ?
JZ GM10 ; Yes - Jump
CMP AL,-1 ; Is it a border square ?
CMP AL,-1 ; Is it a boarder square ?
JZ GM10 ; Yes - Jump
MOV [P1],AL ; Save piece
MOV BX,COLOR ; Address of color of piece
@@ -844,9 +885,11 @@ GM10: MOV AL,[M1] ; Fetch current board position
JNZ GM5 ; No - Jump
RET ; Return
;***********************************************************
;************************************************************
; CHECK ROUTINE
;***********************************************************
;************************************************************
; FUNCTION: -- To determine whether or not the
; King is in check.
;
@@ -857,7 +900,7 @@ GM10: MOV AL,[M1] ; Fetch current board position
; CALLS: -- ATTACK
;
; ARGUMENTS: -- Color of King
;***********************************************************
;************************************************************
INCHK: MOV AL,[COLOR] ; Get color
INCHK1: MOV BX,POSK ; Addr of white King position
AND AL,AL ; White ?
@@ -871,9 +914,11 @@ IC5: MOV AL,[BX] ; Fetch King position
AND AL,7 ; Get piece type
MOV [T1],AL ; Save
;***********************************************************
;************************************************************
; ATTACK ROUTINE
;***********************************************************
;************************************************************
; FUNCTION: -- To find all attackers on a given square
; by scanning outward from the square
; until a piece is found that attacks
@@ -881,7 +926,7 @@ IC5: MOV AL,[BX] ; Fetch King position
; doesn't attack that square, or the edge
; of the board is reached.
;
; In determining which pieces attack
; In determining which pieces attack
; a square, this routine also takes into
; account the ability of certain pieces to
; attack through another attacking piece. (For
@@ -891,7 +936,7 @@ IC5: MOV AL,[BX] ; Fetch King position
; queen, since both participate in the
; attack.
;
; In the case where this routine is called
; In the case where this routine is called
; by CASTLE or INCHK, the routine is
; terminated as soon as an attacker of the
; opposite color is encountered.
@@ -905,7 +950,7 @@ IC5: MOV AL,[BX] ; Fetch King position
; ATKOUT
;
; ARGUMENTS: -- None
;***********************************************************
;************************************************************
ATTACK: PUSH CX ; Save Register CX
MOV BP,[M3] ; Get piece index
ADD BP,BOARD ; Add board pointer to it
@@ -945,9 +990,11 @@ AT20: MOV SI,DIRECT+TBASE ; Load direction table
POP CX ; Restore CX reg
RET ; Return
;***********************************************************
;************************************************************
; ATTACK ADJACENT SCAN ROUTINE
;***********************************************************
;************************************************************
; FUNCTION: -- To scan for a specified attacker on adjacent
; squares.
;
@@ -956,7 +1003,7 @@ AT20: MOV SI,DIRECT+TBASE ; Load direction table
; CALLS: -- ATKCHK
;
; ARGUMENTS: -- The piece under attack. The attacker.
;***********************************************************
;************************************************************
ATKADJ: MOV CX,8 ; 8 directions to scan
AA5: XCHG AX,BX ; Save AX
LODB ; Get direction byte
@@ -972,9 +1019,11 @@ AA5: XCHG AX,BX ; Save AX
AA10: LOOP AA5 ; Go check for next direction
RET ; Return
;***********************************************************
;************************************************************
; ATTACK OUTWARD SCAN ROUTINE
;***********************************************************
;************************************************************
; FUNCTION: -- To scan for a specified attacker outwards
; from the piece under attack, until found
; or edge of the board is reached.
@@ -984,7 +1033,7 @@ AA10: LOOP AA5 ; Go check for next direction
; CALLS: -- ATKCHK
;
; ARGUMENTS: -- The piece under attack. The attacker.
;***********************************************************
;************************************************************
ATKOUT: MOV CL,4 ; 4 directions to scan
AO5: MOV DX,0C0H ; Bitmask for color flags
XCHG AX,BX ; Save AX
@@ -1014,9 +1063,11 @@ AO22: MOV AL,[DI] ; Get piece
CALL ATKCHK ; Check and save attack
JP AO10 ; Keeping going that direction
;***********************************************************
;************************************************************
; ATTACK CHECK AND SAVE ROUTINE
;***********************************************************
;************************************************************
; FUNCTION: -- To check if a piece can attack the target
; square and save the attacking piece value
; in the attack list.
@@ -1036,7 +1087,7 @@ AO22: MOV AL,[DI] ; Get piece
; CALLS: -- None
;
; ARGUMENTS: -- The attacking piece. The piece under attack.
;***********************************************************
;************************************************************
ATKCHK: MOV AL,[DI] ; Get piece
CMP B,[T1],7 ; Call from POINTS ?
JZ ACK10 ; Yes - jump
@@ -1119,9 +1170,11 @@ ACK40: MOV [DI],AL ; Put back into attack list
POP CX
RET ; Return
;***********************************************************
;************************************************************
; PIN FIND ROUTINE
;***********************************************************
;************************************************************
; FUNCTION: -- To produce a list of all pieces pinned
; against the King or Queen, for both white
; and black.
@@ -1133,14 +1186,14 @@ ACK40: MOV [DI],AL ; Put back into attack list
; ATTACK
;
; ARGUMENTS: -- None
;***********************************************************
;************************************************************
PINFND: XOR AL,AL ; Zero pin count
MOV [NPINS],AL
MOV DX,POSK ; Addr of King/Queen pos list
PF1: MOV BP,DX
MOV AL,[BP] ; Get position of royal piece
AND AL,AL ; Is it on board ?
JNZ PF1A ; Yes- continue
JNZ PF1A ; Yes - continue
JMP PF26
PF1A: CMP AL,-1 ; At end of list ?
JZ RET ; Yes return
@@ -1162,7 +1215,7 @@ PF5: CALL PATH ; Compute next position
JZ PF5 ; Yes - jump
CMP AL,3 ; Off board ?
JZ JPF25 ; Yes - jump
CMP AL,2 ; Piece of same color
CMP AL,2 ; Piece of same color found ?
MOV AL,[M4] ; Load pinned piece position
JZ PF15 ; Yes - jump
AND AL,AL ; Possible pin ?
@@ -1232,9 +1285,11 @@ PF25: INC DI ; Increment direction index
PF26: INC DX ; Incr King/Queen pos index
JMP PF1 ; Jump
;***********************************************************
;************************************************************
; EXCHANGE ROUTINE
;***********************************************************
;************************************************************
; FUNCTION: -- To determine the exchange value of a
; piece on a given square by examining all
; attackers and defenders of that piece.
@@ -1293,9 +1348,10 @@ XC20: ADD DL,CH ; Total points lost
MOV CH,BL ; Prev attckr becomes defender
JMP XC10 ; Jump
;***********************************************************
;************************************************************
; NEXT ATTACKER/DEFENDER ROUTINE
;***********************************************************
;************************************************************
; FUNCTION: -- To retrieve the next attacker or defender
; piece value from the attack list, and delete
; that piece from the list.
@@ -1307,7 +1363,7 @@ XC20: ADD DL,CH ; Total points lost
; ARGUMENTS: -- Attack list addresses.
; Side flag
; Attack list counts
;***********************************************************
;*********************************************************
NEXTAD: INC CL ; Increment side flag
XCHG BX,[HL]
XCHG DX,[DE]
@@ -1336,9 +1392,11 @@ NX6: XCHG BX,[HL]
XCHG CX,[BC] ; Restore regs.
RET ; Return
;***********************************************************
;************************************************************
; POINT EVALUATION ROUTINE
;***********************************************************
;************************************************************
;FUNCTION: -- To perform a static board evaluation and
; derive a score for a given board position
;
@@ -1350,7 +1408,7 @@ NX6: XCHG BX,[HL]
; LIMIT
;
; ARGUMENTS: -- None
;***********************************************************
;**************************************************************
POINTS: XOR AL,AL ; Zero out variables
MOV [MTRL],AL
MOV [BRDC],AL
@@ -1470,7 +1528,7 @@ PT25A: MOV AL,[PTSL] ; Get max points lost
JZ PT26 ; Yes - jump
DEC AL ; Decrement it
PT26: MOV CH,AL ; Save it
MOV AL,[PTSW1] ; Max,points won
MOV AL,[PTSW1] ; Max points won
AND AL,AL ; Is it zero ?
JZ PT27 ; Yes - jump
MOV AL,[PTSW2] ; 2nd max points won
@@ -1514,9 +1572,11 @@ PT30: ADD AL,80H ; Rescale score (neutral = 80H)
MOV [SI+MLVAL],AL ; Save score in move list
RET ; Return
;***********************************************************
; LIMIT ROUTINE
;***********************************************************
;**********************************************************
; FUNCTION: -- To limit the magnitude of a given value
; to another given value.
;
@@ -1524,11 +1584,11 @@ PT30: ADD AL,80H ; Rescale score (neutral = 80H)
;
; CALLS: -- None
;
; ARGUMENTS: -- Input - Value, to be limited in the CH
; ARGUMENTS: -- Input - Value to be limited in the CH
; register.
; - Value to limit to in the AL register
; - Value to limit to in the AL register.
; Output - Limited value in the AL register.
;***********************************************************
;************************************************************
LIMIT: TEST CH,080H ; Is value negative ?
JZ LIM10 ; No - jump
NEG AL ; Make positive
@@ -1541,6 +1601,8 @@ LIM10: CMP AL,CH ; Compare to limit
MOV AL,CH ; Output value as is
RET ; Return
;***********************************************************
; MOVE ROUTINE
;***********************************************************
@@ -1556,7 +1618,7 @@ LIM10: CMP AL,CH ; Compare to limit
; CALLS: -- None
;
; ARGUMENTS: -- None
;***********************************************************
;************************************************************
MOVE: MOV BX,[MLPTRJ] ; Load move list pointer
INC BX ; Increment past link bytes
INC BX
@@ -1609,12 +1671,14 @@ MV30: MOV BX,POSK ; Get saved King position
OR DL,010H ; Set King castled flag
JMP MV21 ; Jump
MV40: MOV BX,[MLPTRJ] ; Get move list pointer
ADD BX,8 ; Increment to next move
ADD BX,8 ; Increment to next move
JMP MV1 ; Jump (2nd part of dbl move)
;***********************************************************
;**********************************************************
; UN-MOVE ROUTINE
;***********************************************************
;**********************************************************
; FUNCTION: -- To reverse the process of the move routine,
; thereby restoring the board array to its
; previous position.
@@ -1627,7 +1691,7 @@ MV40: MOV BX,[MLPTRJ] ; Get move list pointer
; CALLS: -- None
;
; ARGUMENTS: -- None
;***********************************************************
;*************************************************************
UNMOVE: MOV BX,[MLPTRJ] ; Load move list pointer
INC BX ; Increment past link bytes
INC BX
@@ -1688,9 +1752,11 @@ UM40: MOV BX,[MLPTRJ] ; Load move list pointer
ADD BX,8 ; Increment to next move
JMP UM1 ; Jump (2nd part of dbl move)
;***********************************************************
;**********************************************************
; SORT ROUTINE
;***********************************************************
;**********************************************************
; FUNCTION: -- To sort the move list in order of
; increasing move value scores.
;
@@ -1699,7 +1765,7 @@ UM40: MOV BX,[MLPTRJ] ; Load move list pointer
; CALLS: -- EVAL
;
; ARGUMENTS: -- None
;***********************************************************
;*************************************************************
SORTM: MOV CX,[MLPTRI] ; Move list begin pointer
MOV DX,0 ; Initialize working pointers
SR5: MOV BH,CH
@@ -1734,13 +1800,15 @@ SR25: MOV [BX],CH ; Link new move into list
SR30: XCHG DX,BX ; Swap pointers
JMP SR15 ; Jump
;***********************************************************
;**********************************************************
; EVALUATION ROUTINE
;***********************************************************
;**********************************************************
; FUNCTION: -- To evaluate a given move in the move list.
; It first makes the move on the board, then if
; the move is legal, it evaluates it, and then
; restores the board position.
; restores the boaard position.
;
; CALLED BY: -- SORT
;
@@ -1748,10 +1816,10 @@ SR30: XCHG DX,BX ; Swap pointers
; INCHK
; PINFND
; POINTS
; UNMOVE
; UNMOV
;
; ARGUMENTS: -- None
;***********************************************************
;*************************************************************
EVAL: CALL MOVE ; Make move on the board array
CALL INCHK ; Determine if move is legal
AND AL,AL ; Legal move ?
@@ -1763,9 +1831,11 @@ EV5: CALL PINFND ; Compile pinned list
CALL POINTS ; Assign points to move
JMP UNMOVE ; Restore board array
;***********************************************************
;*********************************************************
; FIND MOVE ROUTINE
;***********************************************************
;*********************************************************
; FUNCTION: -- To determine the computer's best move by
; performing a depth first tree search using
; the techniques of alpha-beta pruning.
@@ -1777,11 +1847,11 @@ EV5: CALL PINFND ; Compile pinned list
; GENMOV
; SORTM
; ASCEND
; UNMOVE
; UNMOV
;
; ARGUMENTS: -- None
;***********************************************************
FNDMOV: MOV AL,[MOVENO] ; Current move number
;************************************************************
FNDMOV: MOV AL,[MOVENO] ; Currnet move number
CMP AL,1 ; First move ?
JNZ L0003
CALL BOOK ; Yes - execute book opening
@@ -1808,7 +1878,7 @@ FM1: MOV [BX],AL
JNZ FM1
MOV [BC0],AL ; Zero ply 0 board control
MOV [MV0],AL ; Zero ply 0 material
CALL PINFND ; Compile pin list
CALL PINFND ; Complie pin list
CALL POINTS ; Evaluate board at ply 0
MOV AL,[BRDC] ; Get board control points
MOV [BC0],AL ; Save
@@ -1846,7 +1916,7 @@ FM15A: MOV [MLPTRJ],DX ; Save current move pointer
JC FM18 ; Jump if not max
CALL MOVE ; Execute move on board array
CALL INCHK ; Check for legal move
AND AL,AL ; Is move legal
AND AL,AL ; Is move legal ?
JZ FM16 ; Yes - jump
CALL UNMOVE ; Restore board position
JMP FM15 ; Jump
@@ -1933,18 +2003,20 @@ FM37: CMP AL,[BX] ; Compare to score 2 ply above
FM40: CALL ASCEND ; Ascend one ply in tree
JMP FM15 ; Jump
;***********************************************************
;**********************************************************
; ASCEND TREE ROUTINE
;***********************************************************
; FUNCTION: -- To adjust all necessary parameters to
; ascend one ply in the tree.
;*********************************************************
; FUNCTION: -- To adjust all necessary parameters to
; ascend one ply in the tree.
;
; CALLED BY: -- FNDMOV
; CALLED BY: -- FNDMOV
;
; CALLS: -- UNMOVE
; CALLS: -- UNMOV
;
; ARGUMENTS: -- None
;***********************************************************
; ARGUMENTS: -- None
;************************************************************
ASCEND: XOR B,[COLOR],80H ; Toggle color, is new color white ?
JNS AC5 ; Yes - jump
DEC B,[MOVENO] ; Decrement move number
@@ -1962,9 +2034,11 @@ AC5: DEC [SCRIX] ; Decrement score table index
MOV [MLPTRJ],DX ; Save next move pointer
JMP UNMOVE ; Restore board to previous ply
;***********************************************************
;**********************************************************
; ONE MOVE BOOK OPENING
; **********************************************************
;*********************************************************
; FUNCTION: -- To provide an opening book of a single
; move.
;
@@ -2002,6 +2076,8 @@ BM5: ADD B,[BX],6 ; Increment to black moves
BM9: ADD B,[BX],3 ; (P-Q4)
RET ; Return to CPTRMV
;***********************************************************
; COMPUTER MOVE ROUTINE
;***********************************************************
@@ -2057,12 +2133,14 @@ CP24: MOV AL,[SCORE+1] ; Check again for mates
CALL FCDMAT ; Full checkmate ?
RET ; Return
;***********************************************************
; FORCED MATE HANDLING
;***********************************************************
; FUNCTION: -- To examine situations where there exits
; a forced mate and determine whether or
; not the current move is checkmate. If it is,
; not the current move is checkmate. If it is,
; a losing player is offered another game,
; while a loss for the computer signals the
; King to tip over in resignation.
@@ -2104,9 +2182,11 @@ FM08: POP BX ; Remove return addresses
CALL SYSTEM
JMP DRIVER ; Jump (Rest of game init)
;***********************************************************
; BOARD INDEX TO ASCII SQUARE NAME
;***********************************************************
;************************************************************
; FUNCTION: -- To translate a hexadecimal index in the
; board array into an ascii description
; of the square in algebraic chess notation.
@@ -2117,7 +2197,7 @@ FM08: POP BX ; Remove return addresses
;
; ARGUMENTS: -- Board index input in register DH and the
; Ascii square name is output in register BX.
;***********************************************************
;************************************************************
BITASN: SUB AL,AL ; Get ready for division
MOV DL,10
CALL DIVIDE ; Divide
@@ -2129,6 +2209,8 @@ BITASN: SUB AL,AL ; Get ready for division
MOV BH,AL ; Save
RET ; Return
;***********************************************************
; PLAYERS MOVE ANALYSIS
;***********************************************************
@@ -2142,7 +2224,7 @@ BITASN: SUB AL,AL ; Get ready for division
; VALMOV
;
; ARGUMENTS: -- None
;***********************************************************
;************************************************************
PLYRMV: MOV DX,BUFFER ; Ask for input
MOV CL,INBUF
CALL SYSTEM
@@ -2178,9 +2260,11 @@ PL08: MOV DX,INVAL ; Output "INVALID MOVE--TRY AGAIN"
CALL SYSTEM
JP PLYRMV ; Jump
;***********************************************************
;************************************************************
; ASCII SQUARE NAME TO BOARD INDEX
;***********************************************************
;************************************************************
; FUNCTION: -- To convert an algebraic square name in
; Ascii to a hexadecimal board index.
; This routine also checks the input for
@@ -2193,7 +2277,7 @@ PL08: MOV DX,INVAL ; Output "INVALID MOVE--TRY AGAIN"
; ARGUMENTS: -- Accepts the square name in pointer BX
; and outputs the board index in register AL.
; CF = 0 if ok. CF = 1 if invalid.
;***********************************************************
;************************************************************
ATBINX: INC BX ; Increment pointer to skip a char
ASNTBI: MOV AL,[BX] ; Ascii file letter (a - h)
INC BX
@@ -2219,6 +2303,8 @@ ASNTBI: MOV AL,[BX] ; Ascii file letter (a - h)
ADD AL,21
RET ; Return
;***********************************************************
; VALIDATE MOVE SUBROUTINE
;***********************************************************
@@ -2233,7 +2319,7 @@ ASNTBI: MOV AL,[BX] ; Ascii file letter (a - h)
;
; ARGUMENTS: -- Returns flag in register AL, 0 for valid
; and 1 for invalid move.
;***********************************************************
;************************************************************
VALMOV: MOV BX,[MLPTRJ] ; Save last move pointer
PUSH BX ; Save register
MOV AL,[KOLOR] ; Computers color
@@ -2272,9 +2358,11 @@ VA10: MOV AL,1 ; Set flag for invalid move
MOV [MLPTRJ],BX ; Save move pointer
RET ; Return
;***********************************************************
;************************************************************
; POSITIVE INTEGER DIVISION
;***********************************************************
;************************************************************
DIVIDE: PUSH CX
MOV CH,8
DD04: SAL DH
@@ -2289,6 +2377,11 @@ DD06: DEC CH
POP CX
RET
;*******************************************************
; STANDARD MESSAGES
;*******************************************************
CLRMSG: DB 13,10,"Choose your color (W/B): $"
PLYDEP: DB 13,10,"Ply depth (1-6): $"
MVEMSG: DB " ",13,10,"$"
@@ -2305,4 +2398,4 @@ IY: DS 2
BC: DS 2
DE: DS 2
HL: DS 2