Abstract: The disclosure describes an improved apparatus and method for performing an arithmetic operation and multibit shift on two digital numbers during a single pass of the numbers through the arithmetic and shifting apparatus. In order to reduce the time required for the operation, the digital numbers are stored in registers which can be read simultaneously.

Abstract: The disclosure describes improved microprogramming apparatus for a data processor. The improved apparatus includes a translating diode matrix which translates the operation code of a macroinstruction being executed into a predetermined address of a microinstruction stored in a read-only memory. For each operation code being executed, the translating diode matrix is capable of reading two different microinstructions held at two different addresses. This technique enables the sharing of microinstructions by macroinstructions requiring common execution techniques. Logic circuitry is also provided to enable conditional branching of the microprogram.