Cache memory having a multiplexor assembly for ordering output on a data

Abstract

A CPU is coupled to the cache memory over a system bus having a width of 64 data bits. The cache memory is organized into a left array and a right array, with data bits stored as lines of data wherein each line is comprised of 256 data bits defined into four data 'chunks' of 64 bits each. Each memory read access by the CPU to the cache results in a complete line of data to be read in the cache. The chunks comprising the line of data are coupled over an internal cache bus to a 'chunk' multiplexor. The chunk multiplexor stages the data chunks in an order defined by the CPU, and sequentially send the data chunks over the system bus to the CPU. The chunks are organized as high and low order chunks. The multiplexor includes a first multiplexor for receiving the high order chunks and a second multiplexor for receiving the low order chunks. Latches are provided which are coupled to the first and second multiplexors to receive the high order chunks upon the receipt of a first clock signal, and the low order chunks upon the receipt of a second clock signal. Enabling signals are provided to the latches such that the high order and low order chunks are coupled to the system bus in a sequential order which is determined by the CPU.