+
+/* Returns X / Y, rounding up. X must be nonnegative to round correctly. */
+#define DIV_ROUND_UP(X, Y) (((X) + ((Y) - 1)) / (Y))
+
+/* Returns X rounded up to the nearest multiple of Y. */
+#define ROUND_UP(X, Y) (DIV_ROUND_UP(X, Y) * (Y))
+
+/* Returns X rounded down to the nearest multiple of Y. */