Abstract: A pipelined CPU executes instructions of variable length, and references memory using various data widths. Macroinstruction pipelining is employed (instead of microinstruction pipelining), with queueing between units of the CPU to allow flexibility in instruction execution times. A branch prediction method employs a branch history table which records the taken vs. not-taken history of branch opcodes recently used, and uses an empirical aglorithm to predict which way the next occurrence of this branch will go, based upon the history table. The branch history table stores in each entry a number of bits for each branch address, each bits indicating "taken" or "not-taken" for one occurrence of the branch. The table is indexed by branch address. A register stores the empirical aglorithm, and upon occurrence of a branch its history is fetched from the table and used to select a location in the register containing a prediction for this particular pattern of branch history.