diff -r ffd452cf05ff -r b980a7192b5a src/chess/pawn.c
--- a/src/chess/pawn.c	Tue Jun 03 08:43:17 2025 +0200
+++ b/src/chess/pawn.c	Wed Jun 04 23:56:40 2025 +0200
@@ -30,21 +30,21 @@
 #include "pawn.h"
 #include "rules.h"
 
-_Bool pawn_chkrules(GameState *gamestate, Move *move) {
+bool pawn_chkrules(GameState *gamestate, Move *move) {
     int8_t d = ((move->piece & COLOR_MASK) == WHITE ? -1 : 1);
     
     if (move->torow == (d < 0 ? 7 : 0)) {
         if (move->promotion) {
             uint8_t promopiece = move->promotion & PIECE_MASK;
             if (!promopiece || promopiece == PAWN || promopiece == KING) {
-                return 0;
+                return false;
             }
         } else {
-            return 0;
+            return false;
         }
     } else {
         if (move->promotion) {
-            return 0;
+            return false;
         }
     }
     
@@ -57,7 +57,7 @@
                 (gamestate->board[move->fromrow][move->tofile]
                 & ENPASSANT_THREAT);
         } else {
-            return 0;
+            return false;
         }
     } else {
         if (move->fromfile == move->tofile) {
@@ -65,12 +65,12 @@
                 (move->fromrow == (d < 0 ? 1 : 6) && /* advanced first move */
                 move->fromrow == move->torow + d*2);
         } else {
-            return 0;
+            return false;
         }
     }
 }
 
-_Bool pawn_isblocked(GameState *gamestate, Move *move) {
+bool pawn_isblocked(GameState *gamestate, Move *move) {
     if (move->torow == move->fromrow + 1 || move->torow == move->fromrow - 1) {
         return mdst(gamestate->board, move) && !move->capture;
     } else {