Bugfix on new castling method

Copying the Rook square in stead of growing a Rook was done after the
Rook square had already been cleared. In addition the Rook ended up on
d1 for e1b1 castling. To fix that, the alternated step vector had to be
calculated in advance, before being sure it would be applied, to be
available in the castling code. The variable v is now used as a
temporary for that, as it was available after the score is minimaxed.

diff --git a/fairymax.c b/fairymax.c
index a367ca3..92bf8a9 100644 (file)
--- a/fairymax.c
+++ b/fairymax.c
@@ -184,8 +184,8 @@ int k,q,l,e,E,z,n;      /* (q,l)=window, e=current eval. score, E=e.p. sqr.*/
        v=d-1?e:i-p;                            /*** MVV/LVA scoring if d=1**/\r
        if(d-!t>1)                              /*** all captures if d=2  ***/\r
        {v=centr[p]?b[x+257]-b[y+257]:0;        /* center positional pts.   */\r
+        if(!(G&S))b[FF]=b[G],v+=50;            /* castling: put R & score  */\r
         b[G]=b[H]=b[x]=0;b[y]=u|32;            /* do move, set non-virgin  */\r
-        if(!(G&S))b[FF]=k+6,v+=50;             /* castling: put R & score  */\r
         v-=w[p]>0|R<EG?0:20;                   /*** freeze K in mid-game ***/\r
         if(p<3)                                /* pawns:                   */\r
         {v-=9*((x-2&M||b[x-2]-u)+              /* structure, undefended    */\r
@@ -226,7 +226,7 @@ int k,q,l,e,E,z,n;      /* (q,l)=window, e=current eval. score, E=e.p. sqr.*/
         }                                      /*   K-capt. replies)       */\r
         J=f;Z=g;\r
         SHAMAX( pl[k]+=!!t; )\r
-        b[G]=k+6;b[FF]=b[y]=0;b[x]=u;b[H]=t;   /* undo move,G can be dummy */\r
+        b[G]=b[FF];b[FF]=b[y]=0;b[x]=u;b[H]=t; /* undo move,G can be dummy */\r
        }                                       /*          if non-castling */\r
        if(z&S&&Post&K==I&d>2&v>V&v<l){int *p=ps;char X,Y;\r
         printf("%2d ",d-2);\r
@@ -235,20 +235,21 @@ int k,q,l,e,E,z,n;      /* (q,l)=window, e=current eval. score, E=e.p. sqr.*/
         while(*p){X=*p>>8;Y=*p++;\r
         printf(" %c%c%c%c",'a'+(X&15),'8'-(X>>4),'a'+(Y&15),'8'-(Y>>4&7));}\r
         printf("\n");fflush(stdout);\r
-       }       if(v>m)                                 /* new best, update max,best*/\r
+       }
+       if(v>m)                                 /* new best, update max,best*/\r
         m=v,X=x,Y=y|S&F;                       /* mark non-double with S   */\r
        if(h){h=0;goto A;}                      /* redo after doing old best*/\r
       }\r
-      s=t;\r
+      s=t;v=r^flag>>12;                        /* calc. alternated vector  */\r
       if(flag&15^4|u&32||                      /* no double or moved before*/\r
          p>2&&                                 /* no P & no lateral K move,*/\r
          ((b[G=r<0?x&~15:BW-1|x&112]^32)<33    /* no virgin R in corner G, */\r
-         ||b[G^1]|b[G^2]|b[FF=r<0?G+3:G-2])    /* no 2 empty sq. next to R */\r
+         ||b[G^1]|b[G^2]|b[FF=y+v-r])          /* no 2 empty sq. next to R */\r
         )t+=flag&4;                            /* fake capt. for nonsliding*/\r
       else F=y;                                /* enable e.p.              */\r
       if(s&&flag&8)t=0,flag^=flag>>4&15;       /* hoppers go to next phase */\r
       if(!(flag&S))                            /* zig-zag piece?           */\r
-       r^=flag>>12,flag^=flag>>4&15;           /* alternate vector & mode  */\r
+       r=v,flag^=flag>>4&15;                   /* alternate vector & mode  */\r
      }W(!t);                                   /* if not capt. continue ray*/\r
    }}\r
    if((++x&15)>=BW)x=x+16&112;                 /* next sqr. of board, wrap */\r