1. A circuit, comprising: a first set of registers; a second set of registers coupled with the first set of registers, the second set of registers to be written via one or more write operations addressed to one or more registers of the first set, wherein an address to select one from the second set is stored in at least one register of the first set; and a read controller coupled with the first and second sets of registers, the read controller to selectively output a portion of data stored in the first and second sets of registers based on data stored in one or more registers of the second set.