Siemens Aktiengesellschaft

Werner Boening

Rod Fleck

Helmut Stettmaier

A microprocessor assembly includes an integrated microprocessor and an external bus having a plurality of signal lines and a corresponding number of terminals connected to the integrated microprocessor. The integrated microprocessor includes a plurality of terminals; a core processor; at least one quasi-external bus having a plurality of signal lines; a bus control unit connecting the core processor to the quasi-external bus; a device connecting the quasi-external bus to the external bus through a corresponding number of terminals; and at least one peripheral connected to the quasi-external bus. The quasi-external bus has at least the same number of signal lines carrying the same signal as the external bus, and the quasi-external bus has the same control performance as the external bus, for connecting a peripheral without modification to both the external bus and the quasi-external bus.

Integrated microprocessor with internal bus and on-chip peripheral

A correction circuit for arithmetic operations with non-hexadecimal operands in hexadecimal arithmetic units incorporates a full hexadecimal adder for each four-bit word of the operands, a carry storage register coupled to a carry output of the full adder and to its own output, and a coupling circuit for selectively coupling to an operand input of the full adder an operand or a correction factor or the output of the carry storage register. The adder has a second operand input and an output which is connected to a memory for storing a sum output of the adder. The coupling circuits are controllable so that a carry produced by arithmetic operations involving two operands is stored in the carry storage register. In a subsequent arithmetic operation involving the sum of the first arithmetic opration and a correction factor, the carry storage register is connected to its own output and to the carry output of the adder. In a third arithmetic operation the output of the carry storage register is connected to the operand input which corresponds to the correction factor while the correction factor is being added or subtracted to the previously produced sum.

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Munchen, Germany

Werner Boening