is_legal: fix check+pinned and knight check; perft-test + perft2()

src/move-gen.c

@@ -40,6 +40,7 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
     square_t from = move_from(move), to = move_to(move), king = pos->king[us], sq;
     piece_type_t piece = PIECE(pos->board[from]);
     bitboard_t kingbb = pos->bb[us][KING], tmp;
+    u64 pinned = mask(from) & pos->blockers & pos->bb[us][ALL_PIECES];
 
     /* (1) - King
      * For castling, we already tested intermediate squares attacks
@@ -53,14 +54,22 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
 
     /* (2) - King is in check
      * Double-check is already handled, as only K moves were generated.
-     * Here, allowed moves are only on King-attacker line, including
-     * attacker.We can move a piece on
-     * in pseudo move generation, so we only care destination square here.
+     * Here, allowed dest squares are only on King-checker line, or on checker
+     * square.
+     * attacker.
+     * Special cases:
+     *   e.p., legal if the taken pawn is giving check
+     *   pinned piece: always illegal
      */
     if (pos->checkers) {
         if (popcount64(pos->checkers) == 1) {     /* one checker */
             square_t checker = ctz64(pos->checkers);
-            bitboard_t between = bb_between[king][checker];
+            if (pinned)
+                return false;
+            if (is_enpassant(move)) {
+                return pawn_push_up(pos->en_passant, them) == checker;
+            }
+            bitboard_t between = bb_between[king][checker] | pos->checkers;
             return mask(to) & between;
         }
         return false;                             /* double check */
@@ -69,7 +78,8 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
     /* (3) - pinned pieces
      * We verify here that pinned piece P stays on line King-P.
      */
-    if (mask(from) & pos->blockers & pos->bb[us][ALL_PIECES]) {
+    //if (mask(from) & pos->blockers & pos->bb[us][ALL_PIECES]) {
+    if (pinned) {
         bitboard_t line = bb_line[from][king];
         return line & mask(to);                   /* to is not on pin line */
     }

src/search.c

@@ -18,10 +18,11 @@
 #include "position.h"
 #include "move-gen.h"
 #include "move-do.h"
+#include "search.h"
+#include "attack.h"
 
 //#include "move.h"
 //#include "eval.h"
-//#include "search.h"
 
 /**
  * perft() - Perform perft on position
@@ -36,22 +37,22 @@
  */
 u64 perft(pos_t *pos, int depth, int ply)
 {
-    int movetmp = 0, nodes = 0, subnodes, nmove = 0;
+    int subnodes, nmove = 0;
+    u64 nodes = 0;
     movelist_t pseudo = { .nmoves = 0 }, legal = { .nmoves = 0 };
     move_t move;
 
     if (depth == 0)
         return 1;
     pos->checkers = pos_checkers(pos, pos->turn);
-    pos->pinners = pos_king_pinners(pos, pos->turn);
-    pos->blockers = pos_king_blockers(pos, pos->turn, pos->pinners);
+    pos_set_pinners_blockers(pos);
 
     pos_gen_pseudomoves(pos, &pseudo);
     pos_all_legal(pos, &pseudo, &legal);
 
-    //for (nmove = 0; nmove < legal.nmoves; ++nmove ) {
-    while ((move =  pos_next_legal(pos, &pseudo, &movetmp)) != MOVE_NONE) {
-
+    for (nmove = 0; nmove < legal.nmoves; ++nmove ) {
+        //while ((move =  pos_next_legal(pos, &pseudo, &movetmp)) != MOVE_NONE) {
+        //printf("depth=%d movetmp=%d\n", depth, movetmp);
         state_t state;
         move = legal.move[nmove];
         move_do(pos, move, &state);
@@ -64,7 +65,45 @@ u64 perft(pos_t *pos, int depth, int ply)
         move_undo(pos, move, &state);
     }
     if (ply == 1)
-        printf("Total: %d\n", nodes);
+        printf("\nTotal: %lu\n", nodes);
+    return nodes;
+}
+
+u64 perft2(pos_t *pos, int depth, int ply)
+{
+    int subnodes, nmove = 0;
+    u64 nodes = 0;
+    movelist_t pseudo = { .nmoves = 0 };
+    move_t move;
+
+    if (is_in_check(pos, OPPONENT(pos->turn)))
+        return 0;
+    if (depth == 0)
+        return 1;
+    pos->checkers = pos_checkers(pos, pos->turn);
+    pos->pinners = pos_king_pinners(pos, pos->turn);
+    pos->blockers = pos_king_blockers(pos, pos->turn, pos->pinners);
+
+    pos_gen_pseudomoves(pos, &pseudo);
+    //pos_all_legal(pos, &pseudo, &legal);
+
+    for (nmove = 0; nmove < pseudo.nmoves; ++nmove ) {
+        //while ((move =  pos_next_legal(pos, &pseudo, &movetmp)) != MOVE_NONE) {
+        //printf("depth=%d movetmp=%d\n", depth, movetmp);
+        state_t state;
+        move = pseudo.move[nmove];
+        move_do(pos, move, &state);
+        subnodes = perft2(pos, depth - 1, ply + 1);
+
+        if (ply == 1) {
+            char movestr[8];
+            printf("%s: %d\n", move_str(movestr, move, 0), subnodes);
+        }
+        nodes += subnodes;
+        move_undo(pos, move, &state);
+    }
+    if (ply == 1)
+        printf("\nTotal: %lu\n", nodes);
     return nodes;
 }
 

src/search.h

@@ -20,5 +20,6 @@
 //eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color);
 
 u64 perft(pos_t *pos, int depth, int ply);
+u64 perft2(pos_t *pos, int depth, int ply);
 
 #endif  /* SEARCH_H */