*/
static inline uint_fast32_t board_above(int y)
{
- uint_fast32_t val = board_row(y);
-
- return val | (val-1);
+ return ( 0x20ul << 5*y ) - 1;
}
/*
*/
static inline uint_fast32_t board_below(int y)
{
- uint_fast32_t val = board_row(y);
-
- return val | (~val + 1);
+ return ~( 1ul << 5*y ) + 1;
}
/*
return ~val + 0x108421;
}
+/*
+ * Return the board bitmap setting the rectangle of locations that are:
+ *
+ * - on or right of column x1, and
+ * - on or left of column x2, and
+ * - on or below row y1, and
+ * - on or above row y2.
+ *
+ * It must be the case that x2 >= x1 and y2 >= y1.
+ */
+static inline uint_fast32_t board_rect(int x1, int y1, int x2, int y2)
+{
+ return (board_left(x2-x1) << x1) & (board_above(y2-y1) << 5*y1);
+}
+
/*
* Move the bits in the game bitmaps according to a move at position (x, y),
* and update the location of the empty position which, if the move was valid
* is now (x, y).
*
- * Returns 0 if the move was valid (and board has been updated), -1 otherwise.
+ * Returns the board bitmap indicating which positions changed. A return
+ * value of 0 therefore indicates an invalid move.
*/
-int game_do_move(struct board *board, int x, int y);
+uint_fast32_t game_do_move(struct board *board, int x, int y);
/*
* Returns the board bitmap setting game locations that differ from the goal.
*/
void game_begin(struct board *board);
+/*
+ * Return the total elapsed time (in ms) since the last call to game_begin.
+ */
+int_fast32_t game_elapsed(struct board *board);
+
/*
* Disable new moves and clear all tile bits other than the 9 goal tiles.
* Returns the total elapsed time (in ms).