Control store apparatus having dual mode operation handling mechanism

摘要

A writeable control store in a data processing system is provided with a dual mode capability. Coupled with the control store in the system is a central processing unit which may provide the next address of the control store's memory dependent upon the mode of the control store. Otherwise, also dependent upon such mode, the control store memory is addressed, dependent upon the results of tests conducted in the central processing unit, by one of at least two alternative addresses. The control words addressed in the writeable control store are used to control the operation of the central processing unit.