NIBBEL- OCH ORDADRESSERBART MINNE FOER UPPSOEKNING AV PAO VARANDRA FOELJANDE DATAENHETER SOM STOED FOER DECIMAL-ARITMETISKA OPERATIONER.

摘要

A data processing system having a central processing unit (CPU) capable of performing binary and decimal arithmetic software instructions is described. The CPU includes a microprocessor which executes the binary arithmetic software instructions under firmware control. The CPU also includes commercial instruction logic which is used in conjunction with the microprocessor to execute decimal arithmetic operations. The commercial instruction logic also operates under firmware control with the addressing of the firmware microinstructions being controlled by the microprocessor. Also disclosed is the method by which the CPU performs decimal addition, subtraction, multiplication and division arithmetic operations and the method used to convert a number in binary format to a number in a decimal format and the method used to convert a number in a decimal format to a number in binary format.