1 files changed, 24 insertions, 0 deletions
diff --git a/src/new.c b/src/new.c
new file mode 100644
index 0000000..3bdd6d0
--- /dev/null
+++ b/src/new.c
@@ -0,0 +1,24 @@
+#include <stdint.h>
+
+static const uint64_t divtab[244] = {
+	[1] = 0xffffffff + 1l,
+	[3] = 0x55555555 + 1l,
+	[9] = 0x1c71c71c + 1l,
+	[27] = 0x097b425e + 1l,
+	[81] = 0x0329161f + 1l,
+	[243] = 0x010db20a + 1l
+};
+
+#define FASTDIV(n, C) (((n) * (C)) >> 32)
+#define FASTMOD(n, d, C) ((n) - (d) * FASTDIV((n), (C)))
+
+int new(int i, int x, int y)
+{
+	uint64_t A, B, C;
+
+	A = FASTDIV(i, divtab[y]);
+	B = FASTMOD(A, 3, divtab[3]);
+	C = FASTMOD(A + (uint64_t)x, 3, divtab[3]);
+
+	return i + (C - B) * y;
+}