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Computer Chess Created In 487 Bytes, Breaks 32-Year-Old Record

Posted by Soulskill on from the go-small-or-go-home dept.

An anonymous reader writes: The record for smallest computer implementation of chess on any platform was held by 1K ZX Chess, which saw a release back in 1983 for the Sinclair ZX81. It uses just 672 bytes of memory, and includes most chess rules as well as a computer component to play against. The 32-year-old record has been beaten this week by the demoscene group Red Sector Inc. They have implemented a fully-playable version of chess called BootChess in just 487 bytes (readme file including source code).

13 of 204 comments (clear)

  1. Incredible! by DigitAl56K · · Score: 5, Funny

    Next you'll be telling me you can create operating systems in less than 15GB!

    1. Re:Incredible! by Dutch+Gun · · Score: 5, Insightful

      I've noticed that they take a fairly liberal definition of "chess", as they simply discard certain rules, such as en passant pawn capture or castling moves, which are pretty important chess moves. It's a bit hard to argue that this is really "chess" if they just decide to leave out inconvenient rules ("chess lite?"). I probably wouldn't complain about other ommissions such as the 3-repetition rule, but castling?

      Even so, a very cool accomplishment in micro-optimization techniques.

      --
      Irony: Agile development has too much intertia to be abandoned now.
    2. Re:Incredible! by Tablizer · · Score: 5, Funny

      Next you'll be telling me you can create operating systems in less than 15GB!

      If you complain, we'll re-write it in Java and make it 30GB

      --
      Table-ized A.I.
    3. Re:Incredible! by Anonymous Coward · · Score: 5, Interesting

      I've noticed that they take a fairly liberal definition of "chess", as they simply discard certain rules, such as en passant pawn capture or castling moves, which are pretty important chess moves. It's a bit hard to argue that this is really "chess" if they just decide to leave out inconvenient rules ("chess lite?"). I probably wouldn't complain about other ommissions such as the 3-repetition rule, but castling?

      Hmmm ... Read your history of chess - Modern Chess is a variant called "Mad Queen" - there are more variants of chess than there are of Poker, and just because we have become used to an agreed-upon standard does not invalidate other styles ...

    4. Re:Incredible! by hcs_$reboot · · Score: 4, Informative

      To be fair, the ZX81 had only 1k of RAM. So they had to cut through the chess rules. Nowadays they could of course implement the whole game including all rules. But would that be interesting provided that it couldn't compare to that 1983 program?

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    5. Re:Incredible! by Anonymous Coward · · Score: 5, Insightful

      Modern Chess is not now a variant called Mad Queen. It is a standardized game referred to as Chess and understood world-wide.

      Modern chess may have originated in a game that at one time was referred to as "Mad Queen".

    6. Re:Incredible! by aled · · Score: 4, Informative

      there was a 4KB Java games contest some years http://en.m.wikipedia.org/wiki...

      one of the winning entries was a chess game. May be interesting to check.

      --

      "I think this line is mostly filler"
    7. Re:Incredible! by Minupla · · Score: 4, Informative

      Looking at the comment threads, yes, it appears to be a 'faithful' implementation of the original code's rules, or rather a superset, since it includes the pawn promotion rule and the original did not.

      Min

      --
      On the whole, I find that I prefer Slashdot posts to twitter ones because I don't get limited to 140 chars before
  2. Apple Integer BASIC Chess by beaverdownunder · · Score: 4, Interesting

    0 GOSUB 10000
    1 INPUT "DO YOU WANT INSTRUCTIONS (Y OR N)?",A$: IF A$#"Y" AND A$#"N" THEN 1: IF A$="Y" THEN GOSUB 30000
    2 REF=5: CALL -936
    3 INPUT "COMPUTER TO PLAY WHITE(0) OR BLACK(1)",WHO
    4 IST=0
    5 DIM WC(99),BC(99)
    6 DIM V(6),P(26),C(3)
    7 DIM KING(16)
    8 DIM A(70)
    10 DIM M(120),W(120),B(120),I(6)
    11 DIM G(100)
    12 FOR X=1 TO 120:M(X)=0: NEXT X
    14 FOR X=1 TO 99:W(X)=0:B(X)=0: NEXT X
    15 FOR X=2 TO 9:X1=10*X:X2=X1+1:M(X1)=7:M(X2)=7: NEXT X
    16 DIM STR$(10),FILE$(8),RANK$(8)
    17 FILE$(1)="A":FILE$(2)="B":FILE$(3)="C":FILE$(4)="D":FILE$(5)="E":FILE$(6)="F":FILE$(7)="G":FILE$(8)="H"
    18 RANK$="12345678"
    20 FOR K=1 TO 21:K2=K+99:M(K)=7:M(K2)=7: NEXT K
    22 FOR K=32 TO 39:K2=K+50:M(K)=1:M(K2)=-1: NEXT K
    23 M(22)=4:M(23)=2:M(24)=3:M(25)=5:M(26)=6:M(27)=3:M(28)=2:M(29)=4
    25 FOR K=22 TO 29:K2=K+70:M(K2)=-M(K): NEXT K
    30 I(1)=12:I(2)=15:I(3)=10:I(4)=1:I(5)=6:I(6)=6
    35 V(1)=1:V(2)=3:V(3)=3:V(4)=5:V(5)=9:V(6)=10
    40 P(1)=-1:P(2)=1:P(3)=10:P(4)=-10:P(5)=0:P(6)=1:P(7)=-1
    45 P(8)=10:P(9)=-10:P(10)=-9:P(11)=-11:P(12)=9:P(13)=11:P(14)=0
    50 P(15)=8:P(16)=-8:P(17)=12:P(18)=-12:P(19)=19:P(20)=-19
    55 P(21)=21:P(22)=-21:P(23)=0:P(24)=10:P(25)=20:P(26)=0
    60 C(1)=8:C(2)=0:C(3)=3
    80 IF WHO=1 THEN 90
    85 M(25)=6:M(26)=5:M(95)=-6:M(96)=-5
    90 GOSUB 5000
    93 FOR II=1 TO 120:W(II)=0:B(II)=0: NEXT II
    95 IF WHO=1 THEN 100:T2=0: GOTO 1000
    100 REM MAKE MOVE
    101 GOSUB 4000
    105 Z9=0
    110 GOSUB 4200
    115 GOSUB 5000: IF WHO=0 THEN 1000
    116 M9=M9+1: IF M9>REF THEN 120
    117 IF T2>4 THEN 120: IF IST=1 THEN GOTO 120
    118 F2=9-F2:T2=9-T2: GOSUB 4200: GOSUB 5000: GOTO 100
    120 REM FILL CONTROL ARRAYS
    122 N8=0:IST=1
    125 FOR X1=22 TO 99:WC(X1)=0:BC(X1)=0: IF M(X1)=6 THEN BKING=X1: IF M(X1)=-6 THEN WKING=X1: NEXT X1
    130 FOR X=22 TO 99: IF M(X)<1 THEN 170: IF M(X)=7 THEN 170: GOSUB 8000: IF N9=0 THEN 170
    150 FOR X1=1 TO N9:TO=G(X1)-G(X1)/100*100: IF M(TO)>0 THEN 168
    164 N8=N8+1:A(N8)=G(X1)
    168 BC(TO)=BC(TO)+1
    169 NEXT X1
    170 NEXT X
    172 FOR X=22 TO 99: IF M(X)>-1 THEN 180: GOSUB 8000
    173 IF N9=0 THEN 180
    174 FOR X1=1 TO N9:TO=G(X1)-G(X1)/100*100:WC(TO)=WC(TO)+1
    176 NEXT X1
    180 NEXT X
    181 GOTO 3000: REM CASTLE LOGIC
    182 REM FILL KING CONTROL ARRAY
    184 KING(1)=BKING+1:KING(2)=BKING-1:KING(3)=BKING+10:KING(4)=BKING-10
    185 KING(5)=BKING+11:KING(6)=BKING-11:KING(7)=BKING+9:KING(8)=BKING-9
    186 KING(9)=WKING+1:KING(10)=WKING-1:KING(11)=WKING+10:KING(12)=WKING-10
    187 KING(13)=WKING+11:KING(14)=WKING-11:KING(15)=WKING+9:KING(16)=WKING-9
    190 V9=-10000:I9=0: FOR X4=1 TO N8:N4=0:F4=A(X4)/100
    210 T4=A(X4)-F4*100:F5=M(F4):T5=M(T4)
    212 REM FIND MOVES OFPIECE IN PRESENT POSTION.
    214 X=F4: GOSUB 8000
    225 M(T4)=M(F4):M(F4)=0
    235 GOSUB 9000: IF N4<=V9 THEN 255
    245 V9=N4:F9=F4:T9=T4
    255 M(F4)=F5:M(T4)=T5:
    256 Z9=Z9+1: IF Z9>20 THEN Z9=1: TAB 26: VTAB Z9: PRINT F4;" : ";T4;" V= ";N4
    259 NEXT X4
    270 F1=F9:T1=T9:M(T1)=M(F1):M(F1)=0:F6=F1-F1/10*10-1:F7=10-F1/10:T6=T1-T1/10*10-1:T7=10-T1/10
    280 IF WHO=1 AND F1=22 THEN QROOK=1
    281 IF WHO=1 AND F1=29 THEN KROOK=1
    282 IF M(T1)=6 THEN MKING=1
    283 IF WHO=0 AND F1=22 THEN QROOK=1
    284 IF WHO=0 AND F1=29 THEN KROOK=1
    310 PRINT "FROM ";F6;F7

  3. He was right! by Tablizer · · Score: 4, Funny

    Toldja, 640 bytes otta be enough for anyone. -Gill Bates

    --
    Table-ized A.I.
  4. Re:"includes most chess rules" by Anonymous Coward · · Score: 5, Funny

    They have altered the rules. Pray they do not alter it further.

  5. Its even more impressive... by Viol8 · · Score: 4, Interesting

    ... when you consider the ZX81 chess was written in Z80 assembler whereas this is in x86 asm and although both have variable sized instructions the x86 will on average be larger.

  6. Oh do shut up by Viol8 · · Score: 4, Insightful

    Why can't people like you just appreciate the technical accomplishment instead of nit picking.

    Tell you what - why not go away and try and write any type of chess program then get back to us?

    As someone who has written a chess program which even after some code optimisation still came out at ~3000 lines of C, I can tell you this is damn impressive.