Disclosed is a vector indexed memory unit and method of operation. In one
embodiment a plurality of values are stored in segments of a vector index
register. Individual ones of the values are provided to an associated
operator (e.g., adder or bit replacement). Individual ones of the
operators operates on its associated vector index value and a base value
to generate a memory address. These memory addresses are then
concurrently accessed in one or more memory units. If the data in the
memory units are organized as data tables, the apparatus allows for
multiple concurrent table lookups. In an alternate embodiment, in
addition to the above described operators generating multiple memory
addresses, an adder is provided to add the base value to the value
represented by the concatenation of the bits in the vector index register
to generate a single memory address. Multiplexers controlled by a
programmable mode select signal are used to provide either the multiple
memory addresses or the single memory address to the memory units. This
alternate embodiment provides an apparatus that can programmably function
in either an vector indexed memory mode or a conventional memory
addressing mode.