🚀 go-pugleaf

Please ignore my previous patch.  Its not very correct.  Here is the
correct patch.

Kong Sian

*** /usr/people/kongsian/gnuchess-4.0/src/ttable.c	Tue May 10 05:44:23 1994
--- ttable.c	Fri May 20 15:13:45 1994
***************
*** 234,242 ****
  	HashAdd++;
  #endif
  	if(ptbl->depth > (UCHAR)depth) return false;
-   /* adjust score so moves to mate is from this ply */
- 	if (score > 9000) score += ply;
- 	else if (score < -9000) score -= ply;
  	ptbl->hashbd = hashbd;
  	ptbl->depth = (UCHAR) depth;
  	ptbl->score = score;
--- 234,239 ----
***************
*** 254,260 ****
--- 251,263 ----
  		ptbl->score = beta + 1;
  	  }
  	else
+ 	  {
+                 /* adjust score so moves to mate is from this ply */
+ 	        if (score > 9000) score += ply;
+ 	        else if (score < -9000 && score != -9999) score -= ply;
+                 ptbl->score = score;
  		ptbl->flags = truescore;
+ 	  }
  
  #ifdef HASHSTATS
  	ttdepthin[ptbl->depth]++;