INSTRUCTION FETCH APPARATUS WITH COMBINED LOOK-AHEAD AND LOOK-BEHIND CAPABILITY

摘要

Apparatus for fetching instructions to an instruction register of a central processing unit, including instruction buffers for storing instructions prior to their execution in the CPU (look-ahead) and apparatus for storing instructions which have been executed in the CPU (look-behind) in anticipation of their further use in, for example, programming loops. The look-behind apparatus comprises a multi-word buffer with its associated data register. The buffer data register, in addition to its function as part of the look-behind apparatus, also provides an additional level of look-ahead.