Data processing system with a microprogrammed dispatcher for working either in native or non-native mode

摘要

A data processing system having a common data bus to which access is gained by at least a control store, an arithmetic logic unit (ALU) and an emulator unit (EMU). The control store includes a microprogrammable switch for enabling either the EMU or the ALU to process instructions received on a common bus. Common opcode bits in the instruction are interpreted by either the ALU or the EMU and responded to thereby depending upon the state of a control register in the control store. The instructions are stored in a control store array in the control store coupled with the bus, and allows operation of either the ALU (native mode of operation) or the EMU (non-native mode of operation), dependent upon the microprogram's instruction in the control store thereby giving increased efficiency of operation of the system.