1 files changed, 48 insertions, 0 deletions
diff --git a/board.c b/board.c
new file mode 100644
index 0000000..91cee2a
--- /dev/null
+++ b/board.c
@@ -0,0 +1,48 @@
+#include "board.h"
+
+
+void b_set(board_t B, cboard_t C) {
+	B[0] = C[0];
+	B[1] = C[1];
+}
+
+void b_drop(board_t B, int xy, int v) {
+	u64 mask = 0xfULL << (4 * xy), stkbot = 0x1ULL << (4 * xy);
+	u64 bit = ((B[0] | B[1]) & mask) + stkbot;
+	B[v] = B[v] | bit;
+}
+
+bool b_stk_full(cboard_t B, int xy) {
+	u64 mask = 0xfULL << (4 * xy);
+	return ((B[0] | B[1]) & mask) == mask;
+}
+
+static u64 winmasks[61] = {
+	0xfULL, 0xf0ULL, 0xf00ULL, 0x1111ULL,
+	0x2222ULL, 0x4444ULL, 0x8421ULL, 0x8888ULL,
+	0xf000ULL, 0xf0000ULL, 0xf00000ULL, 0xf000000ULL,
+	0x11110000ULL, 0x22220000ULL, 0x44440000ULL, 0x84210000ULL,
+	0x88880000ULL, 0xf0000000ULL, 0xf00000000ULL, 0xf000000000ULL,
+	0xf0000000000ULL, 0x111100000000ULL, 0x222200000000ULL, 0x444400000000ULL,
+	0x842100000000ULL, 0x888800000000ULL, 0xf00000000000ULL, 0x1000100010001ULL,
+	0x2000200020002ULL, 0x4000400040004ULL, 0x8000400020001ULL, 0x8000800080008ULL,
+	0xf000000000000ULL, 0x10001000100010ULL, 0x20002000200020ULL, 0x40004000400040ULL,
+	0x80004000200010ULL, 0x80008000800080ULL, 0xf0000000000000ULL, 0x100010001000100ULL,
+	0x200020002000200ULL, 0x400040004000400ULL, 0x800040002000100ULL, 0x800080008000800ULL,
+	0xf00000000000000ULL, 0x1000010000100001ULL, 0x1000100010001000ULL, 0x1111000000000000ULL,
+	0x2000020000200002ULL, 0x2000200020002000ULL, 0x2222000000000000ULL, 0x4000040000400004ULL,
+	0x4000400040004000ULL, 0x4444000000000000ULL, 0x8000040000200001ULL, 0x8000080000800008ULL,
+	0x8000400020001000ULL, 0x8000800080008000ULL, 0x8421000000000000ULL, 0x8888000000000000ULL,
+	0xf000000000000000ULL,
+};
+
+enum win_t b_win(cboard_t B) {
+	if ((B[0] | B[1]) == ~0ULL) return WIN_DRAW;
+
+	for (int i = 0; i < (int)(sizeof(winmasks) / sizeof(winmasks[0])); i++) {
+		if ((B[0] & winmasks[i]) == winmasks[i]) return WIN_P0;
+		if ((B[1] & winmasks[i]) == winmasks[i]) return WIN_P1;
+	}
+
+	return WIN_NONE;
+}