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US 3,942,156 AGranted
Indirect arithmetic control
AssigneeXerox Corporation
InventorsHoward C. Mock, Kenneth N. Isaac, Charles P. Disparte, Warren L. Hall
Life of this patent
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AssigneeXerox Corporation
InventorsHoward C. Mock, Kenneth N. Isaac, Charles P. Disparte, Warren L. Hall
Estimating the term…
Circuits for the improved operation of microprogrammable computers are described. This improvement is accomplished by providing a set of read-only memory devices for storing the micro-code for all combinations of arithmetic logic unit function, carry bit and file register address than can be specified by an instruction word executed from Main Memory. In a universal microprogram designed to execute that family of Main Memory instructions that differ only in the functions specified above, the instruction word is used to address the read-only memory devices, the micro-code output of which is used to control the file, carry in bit and arithmetic logic unit. Through the use of these circuits a family of instructions may be executed by a single microprogram and at no increase in execution time over that required for the execution of a microprogram dedicated to a single instruction.
In a microprogrammable computer of the type having data registers, an arithmetic logic unit, control lines for controlling the transfer of data between said data registers and said arithmetic logic unit, and a control memory comprising first circuit for storing microprograms and second circuit for executing said microprograms and for coupling the control information generated by said microprogram execution to said control lines, an improved indirect arithmetic control circuit comprising:
In a microprogrammable computer of the type having control lines for controlling the flow of data between the data registers and the arithmetic logic unit of said computer, and a control memory comprising first circuit for storing microprograms and second circuit for executing said microprograms and for coupling the control information generated thereby to said control lines, an improved indirect arithmetic control circuit comprising:
In a microprogrammable computer of the type having control lines for controlling the flow of data between the data registers and arithmetic logic unit of said computer, a function control register for driving said control lines, and a control memory for storing microprograms in a first circuit of said control memory and for executing said microprograms and for outputting the control information generated by a said microprogram execution by second circuit of said control memory,
The apparatus as set forth in claim 15 wherein said read-only memory device comprises a plurality of read-only memory chips.
Dependencies are inferred from the claim text.