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'''[[Main Page|Home]] * [[Organizations]] * [[ICGA]] * [[ICGA Investigations|Investigations]] * [[Rybka Controversy]] * [[Pre-Fruit Rybka and Crafty]] * Equality of Even Score with 99999'''
'''[[Rybka-Crafty Evidence|< Prev]] [[Rybka-Crafty Evidence III|Next >]]'''
by [[Mark Watkins]]
=Crafty Source=
Here is the Crafty 19.15 code. This code was also mentioned in the [[Historical Examples#ElChinito|ElChinito Case]] <ref>[https://www.stmintz.com/ccc/index.php?id=383344 Re: Correction: List and ElChinito as Crafty clones, ... etc] by Paul H., [[CCC]], August 21, 2004</ref>:
<pre>
if ((TotalWhitePawns + TotalBlackPawns) == 0)
do {
int ms = EvaluateMate(tree);
if (ms == 99999)
break;
score += ms;
#ifdef DEBUGEV
printf("score[mater]= %4d (%+d)\n", score,
score - lastsc);
#endif
if (score > DrawScore(1) && !(can_win & 1))
score = score >> 2;
if (score < DrawScore(1) && !(can_win & 2))
score = score >> 2;
return ((wtm) ? score : -score);
} while (0);
</pre>
=Rybka Assembly=
Here is the function call to something like __EvaluateMate__ in a pre-Beta Rybka disassembly (Zach will likely provide details of how EvaluateMate works, and the closeness of the Rybka/Crafty match there).
<pre>
0x00402b4b: test %ebx,%ebx # test TotalWhitePawns + TotalBlackPawns
0x00402b59: jne 0x402bca # if nonzero, skip all this
0x00402b5b: push %esi
0x00402b5c: call 0x404540 # function call: EvaluateMate
0x00402b61: mov 0x8(%ebp),%ecx # load "score" variable to ecx
0x00402b64: add $0x4,%esp
0x00402b67: cmp $0x1869f,%eax # compare above return value to 99999
0x00402b6c: je 0x402bcd # if equal, then break
0x00402b6e: add %eax,%ecx # score += ms
0x00402b70: mov 0x6b8d7c,%eax # load DrawScore(1)
0x00402b75: cmp %eax,%ecx # compare score to DrawScore(1)
0x00402b77: jle 0x402b84
0x00402b79: testb $0x1,-0x1c(%ebp) # can_win & 1
0x00402b7d: jne 0x402b82
0x00402b7f: sar $0x2,%ecx # shift right by 2 if conditions met
0x00402b82: cmp %eax,%ecx # compare score to DrawScore(1)
0x00402b84: jge 0x402b8f
0x00402b86: testb $0x2,-0x1c(%ebp) # can_win & 2
0x00402b8a: jne 0x402b8f
0x00402b8c: sar $0x2,%ecx # shift right by 2 if conditions met
0x00402b8f: mov 0x10(%ebp),%eax # load wtm
0x00402b92: test %eax,%eax # determine by wtm whether score or -score
0x00402b94: jne 0x402b98
0x00402b96: neg %ecx
0x00402b98: mov %ecx,%eax # et cetera
</pre>
==EvaluateMate==
Here are some relevant parts of that function call (Zach may provide more), enough to show that the return value is always even.
<pre>
FUNCTION_CALL:
0x00404540: mov 0x4(%esp),%ecx
[...]
0x004046b6: lea 0x0(%ebp,%ebp,1),%eax # add ebp to itself for the return value
0x004046ba: pop %ebp
0x004046bb: pop %ebx
0x004046bc: ret
[...]
0x00404717: lea (%edi,%edi,1),%eax # double
0x0040471a: pop %edi
0x0040471b: pop %esi
0x0040471c: pop %ebp
0x0040471d: pop %ebx
0x0040471e: ret
[...]
0x00404729: lea (%edi,%edi,1),%eax # double
0x0040472c: pop %edi
0x0040472d: pop %esi
0x0040472e: pop %ebp
0x0040472f: pop %ebx
0x00404730: ret
0x00404731: pop %edi
0x00404732: lea (%esi,%esi,1),%eax # double
0x00404735: pop %esi
0x00404736: pop %ebp
0x00404737: pop %ebx
0x00404738: ret
</pre>
This is the only calling of 0x404540 in the code, and I've listed all the returns, with no jumps to instructions between a doubling and returning. In particular, the return value is always even, but then is compared for equality with 99999.
This code is largely relevant when mating KBN vs K.
=References=
<references />
'''[[Pre-Fruit Rybka and Crafty|Up one level]]'''
'''[[Rybka-Crafty Evidence|< Prev]] [[Rybka-Crafty Evidence III|Next >]]'''
by [[Mark Watkins]]
=Crafty Source=
Here is the Crafty 19.15 code. This code was also mentioned in the [[Historical Examples#ElChinito|ElChinito Case]] <ref>[https://www.stmintz.com/ccc/index.php?id=383344 Re: Correction: List and ElChinito as Crafty clones, ... etc] by Paul H., [[CCC]], August 21, 2004</ref>:
<pre>
if ((TotalWhitePawns + TotalBlackPawns) == 0)
do {
int ms = EvaluateMate(tree);
if (ms == 99999)
break;
score += ms;
#ifdef DEBUGEV
printf("score[mater]= %4d (%+d)\n", score,
score - lastsc);
#endif
if (score > DrawScore(1) && !(can_win & 1))
score = score >> 2;
if (score < DrawScore(1) && !(can_win & 2))
score = score >> 2;
return ((wtm) ? score : -score);
} while (0);
</pre>
=Rybka Assembly=
Here is the function call to something like __EvaluateMate__ in a pre-Beta Rybka disassembly (Zach will likely provide details of how EvaluateMate works, and the closeness of the Rybka/Crafty match there).
<pre>
0x00402b4b: test %ebx,%ebx # test TotalWhitePawns + TotalBlackPawns
0x00402b59: jne 0x402bca # if nonzero, skip all this
0x00402b5b: push %esi
0x00402b5c: call 0x404540 # function call: EvaluateMate
0x00402b61: mov 0x8(%ebp),%ecx # load "score" variable to ecx
0x00402b64: add $0x4,%esp
0x00402b67: cmp $0x1869f,%eax # compare above return value to 99999
0x00402b6c: je 0x402bcd # if equal, then break
0x00402b6e: add %eax,%ecx # score += ms
0x00402b70: mov 0x6b8d7c,%eax # load DrawScore(1)
0x00402b75: cmp %eax,%ecx # compare score to DrawScore(1)
0x00402b77: jle 0x402b84
0x00402b79: testb $0x1,-0x1c(%ebp) # can_win & 1
0x00402b7d: jne 0x402b82
0x00402b7f: sar $0x2,%ecx # shift right by 2 if conditions met
0x00402b82: cmp %eax,%ecx # compare score to DrawScore(1)
0x00402b84: jge 0x402b8f
0x00402b86: testb $0x2,-0x1c(%ebp) # can_win & 2
0x00402b8a: jne 0x402b8f
0x00402b8c: sar $0x2,%ecx # shift right by 2 if conditions met
0x00402b8f: mov 0x10(%ebp),%eax # load wtm
0x00402b92: test %eax,%eax # determine by wtm whether score or -score
0x00402b94: jne 0x402b98
0x00402b96: neg %ecx
0x00402b98: mov %ecx,%eax # et cetera
</pre>
==EvaluateMate==
Here are some relevant parts of that function call (Zach may provide more), enough to show that the return value is always even.
<pre>
FUNCTION_CALL:
0x00404540: mov 0x4(%esp),%ecx
[...]
0x004046b6: lea 0x0(%ebp,%ebp,1),%eax # add ebp to itself for the return value
0x004046ba: pop %ebp
0x004046bb: pop %ebx
0x004046bc: ret
[...]
0x00404717: lea (%edi,%edi,1),%eax # double
0x0040471a: pop %edi
0x0040471b: pop %esi
0x0040471c: pop %ebp
0x0040471d: pop %ebx
0x0040471e: ret
[...]
0x00404729: lea (%edi,%edi,1),%eax # double
0x0040472c: pop %edi
0x0040472d: pop %esi
0x0040472e: pop %ebp
0x0040472f: pop %ebx
0x00404730: ret
0x00404731: pop %edi
0x00404732: lea (%esi,%esi,1),%eax # double
0x00404735: pop %esi
0x00404736: pop %ebp
0x00404737: pop %ebx
0x00404738: ret
</pre>
This is the only calling of 0x404540 in the code, and I've listed all the returns, with no jumps to instructions between a doubling and returning. In particular, the return value is always even, but then is compared for equality with 99999.
This code is largely relevant when mating KBN vs K.
=References=
<references />
'''[[Pre-Fruit Rybka and Crafty|Up one level]]'''
