+
+ /* Spec 38.322 Section 7.1
+ * All UM state variables can take values from 0 to 63 for 6 bit SN or
+ * from 0 to 4095 for 12 bit SN. All arithmetic operations on UM state
+ * variables are affected by the UM modulus
+ * (i.e. final value = [value from arithmetic operation] modulo 64
+ * for 6 bit SN and 4096 for 12 bit SN)
+ */