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Created page with "'''Home * Organizations * ICGA * Investigations * Rybka Controversy * Pre-Fruit Rybka and Crafty * Rybka-Crafty Evidence..."
'''[[Main Page|Home]] * [[Organizations]] * [[ICGA]] * [[ICGA Investigations|Investigations]] * [[Rybka Controversy]] * [[Pre-Fruit Rybka and Crafty]] * Rybka-Crafty Evidence IV'''
'''[[Rybka-Crafty Evidence III|< Prev]] [[Rybka-Crafty Evidence V|Next >]]'''
by [[Mark Watkins]]
Copied code from the start of Crafty's Evaluate in pre-Beta Rybka.
=Crafty Source=
Here is the start of the Evaluate() code in Crafty 19.1, with some comments removed:
<pre>
int Evaluate(TREE * RESTRICT tree, int ply, int wtm, int alpha, int beta) {
register BITBOARD temp;
register int square, file, score, tscore, w_tropism=0, b_tropism=0;
register int w_spread, b_spread, trop, can_win=3;
// ... comments and #if stuff omitted
if (TotalWhitePieces<13 && TotalBlackPieces<13) {
can_win=EvaluateWinner(tree);
if (EvaluateStalemate(tree,wtm)) can_win=0;
}
if (can_win == 0) return(DrawScore(wtm));
</pre>
=Pre-Beta Rybka Assembly=
Here is the comparative code for pre-Beta Rybka:
<pre>
0x00402a00: push %ebp # start of pre-Beta Rybka Evaluate()
0x00402a01: mov %esp,%ebp
0x00402a03: sub $0x44,%esp
0x00402a06: push %ebx
0x00402a07: mov 0x10(%ebp),%ebx
0x00402a0a: push %esi
0x00402a0b: mov 0x8(%ebp),%esi
0x00402a0e: mov 0xb0a(%esi),%cl # load "TotalWhitePieces"
0x00402a14: mov $0xd,%al # 0xd is 13
0x00402a16: cmp %al,%cl # compare "TotalWhitePieces" to 13
0x00402a18: push %edi
0x00402a19: movl $0x3,-0x1c(%ebp) # set "can_win" to 3
0x00402a20: jge 0x402a53
0x00402a22: cmp %al,0xb0b(%esi) # compare "TotalBlackPieces" to 13
0x00402a28: jge 0x402a53 # if both < 13
0x00402a2a: push %esi
0x00402a2b: call 0x401630 # call EvaluateWinner()
0x00402a30: mov %eax,%edi
0x00402a32: push %ebx
0x00402a33: push %esi
0x00402a34: mov %edi,-0x1c(%ebp) # store function result in "can_win"
0x00402a37: call 0x401130 # call EvaluateStalemate()
0x00402a3c: add $0xc,%esp
0x00402a3f: test %eax,%eax # if EvaluateStalemate() result is nonzero
0x00402a41: jne 0x402a47 # jump to loading DrawScore(wtm) and returning
0x00402a43: test %edi,%edi # if "can_win" is now zero
0x00402a45: jne 0x402a53 # then do the next two lines (else skip)
0x00402a47: mov 0x6b8d78(,%ebx,4),%eax # get DrawScore(wtm), it seems
0x00402a4e: jmp 0x402b9a # jump to function exit...
</pre>
As can be seen, the use of "can_win" is the same (see also the page regarding 99999), as is the comparison to 13.
=ToDo=
Either Zach or Mark will disentangle EvaluateWinner() and EvaluateStalemate() to strengthen the evidence here.
=Sidenote=
As noted by Zach, this pre-Beta Rybka does not return the __DrawScore(wtm)__ value directly, but first does some manipulations with it.
<pre>
0x00402b9a: cltd
0x00402b9b: sub %edx,%eax
0x00402b9d: sar %eax
0x00402b9f: test %eax,%eax
0x00402ba1: jle 0x404519
0x00402ba7: cmp $0x80,%eax
0x00402bac: jl 0x404531
0x00402bb2: add $0xffffff80,%eax
0x00402bb5: cltd
0x00402bb6: and $0xf,%edx
0x00402bb9: add %edx,%eax
0x00402bbc: sar $0x4,%eax
0x00402bc0: add $0x80,%eax
0x00402bc9: ret
[...]
0x00404519: cmp $0xffffff80,%eax
0x0040451c: jg 0x404531
0x0040451e: add $0x80,%eax
0x00404523: cltd
0x00404524: and $0xf,%edx
0x00404527: add %edx,%eax
0x00404529: sar $0x4,%eax
0x0040452c: sub $0x80,%eax
0x00404537: ret
</pre>
I omitted the "pop" and %esp instructions in the last here, as they only have to do with preparing the stack for subroutine exit.
'''[[Pre-Fruit Rybka and Crafty|Up one level]]'''
'''[[Rybka-Crafty Evidence III|< Prev]] [[Rybka-Crafty Evidence V|Next >]]'''
by [[Mark Watkins]]
Copied code from the start of Crafty's Evaluate in pre-Beta Rybka.
=Crafty Source=
Here is the start of the Evaluate() code in Crafty 19.1, with some comments removed:
<pre>
int Evaluate(TREE * RESTRICT tree, int ply, int wtm, int alpha, int beta) {
register BITBOARD temp;
register int square, file, score, tscore, w_tropism=0, b_tropism=0;
register int w_spread, b_spread, trop, can_win=3;
// ... comments and #if stuff omitted
if (TotalWhitePieces<13 && TotalBlackPieces<13) {
can_win=EvaluateWinner(tree);
if (EvaluateStalemate(tree,wtm)) can_win=0;
}
if (can_win == 0) return(DrawScore(wtm));
</pre>
=Pre-Beta Rybka Assembly=
Here is the comparative code for pre-Beta Rybka:
<pre>
0x00402a00: push %ebp # start of pre-Beta Rybka Evaluate()
0x00402a01: mov %esp,%ebp
0x00402a03: sub $0x44,%esp
0x00402a06: push %ebx
0x00402a07: mov 0x10(%ebp),%ebx
0x00402a0a: push %esi
0x00402a0b: mov 0x8(%ebp),%esi
0x00402a0e: mov 0xb0a(%esi),%cl # load "TotalWhitePieces"
0x00402a14: mov $0xd,%al # 0xd is 13
0x00402a16: cmp %al,%cl # compare "TotalWhitePieces" to 13
0x00402a18: push %edi
0x00402a19: movl $0x3,-0x1c(%ebp) # set "can_win" to 3
0x00402a20: jge 0x402a53
0x00402a22: cmp %al,0xb0b(%esi) # compare "TotalBlackPieces" to 13
0x00402a28: jge 0x402a53 # if both < 13
0x00402a2a: push %esi
0x00402a2b: call 0x401630 # call EvaluateWinner()
0x00402a30: mov %eax,%edi
0x00402a32: push %ebx
0x00402a33: push %esi
0x00402a34: mov %edi,-0x1c(%ebp) # store function result in "can_win"
0x00402a37: call 0x401130 # call EvaluateStalemate()
0x00402a3c: add $0xc,%esp
0x00402a3f: test %eax,%eax # if EvaluateStalemate() result is nonzero
0x00402a41: jne 0x402a47 # jump to loading DrawScore(wtm) and returning
0x00402a43: test %edi,%edi # if "can_win" is now zero
0x00402a45: jne 0x402a53 # then do the next two lines (else skip)
0x00402a47: mov 0x6b8d78(,%ebx,4),%eax # get DrawScore(wtm), it seems
0x00402a4e: jmp 0x402b9a # jump to function exit...
</pre>
As can be seen, the use of "can_win" is the same (see also the page regarding 99999), as is the comparison to 13.
=ToDo=
Either Zach or Mark will disentangle EvaluateWinner() and EvaluateStalemate() to strengthen the evidence here.
=Sidenote=
As noted by Zach, this pre-Beta Rybka does not return the __DrawScore(wtm)__ value directly, but first does some manipulations with it.
<pre>
0x00402b9a: cltd
0x00402b9b: sub %edx,%eax
0x00402b9d: sar %eax
0x00402b9f: test %eax,%eax
0x00402ba1: jle 0x404519
0x00402ba7: cmp $0x80,%eax
0x00402bac: jl 0x404531
0x00402bb2: add $0xffffff80,%eax
0x00402bb5: cltd
0x00402bb6: and $0xf,%edx
0x00402bb9: add %edx,%eax
0x00402bbc: sar $0x4,%eax
0x00402bc0: add $0x80,%eax
0x00402bc9: ret
[...]
0x00404519: cmp $0xffffff80,%eax
0x0040451c: jg 0x404531
0x0040451e: add $0x80,%eax
0x00404523: cltd
0x00404524: and $0xf,%edx
0x00404527: add %edx,%eax
0x00404529: sar $0x4,%eax
0x0040452c: sub $0x80,%eax
0x00404537: ret
</pre>
I omitted the "pop" and %esp instructions in the last here, as they only have to do with preparing the stack for subroutine exit.
'''[[Pre-Fruit Rybka and Crafty|Up one level]]'''
