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Patent Searching and Data


Title:
ARITHMETIC CIRCUIT
Document Type and Number:
Japanese Patent JPS6272030
Kind Code:
A
Abstract:

PURPOSE: To perform high-speed, high-precision arithmetic through a small-scale circuit by providing a correcting circuit which makes the binary-coded decimal correction of the output signal of a binary arithmetic circuit and adds zero, and determining which of decimal correction and zero addition is selected with a microcode.

CONSTITUTION: When a microcode for setting a binary arithmetic mode is stored in a program memory 6 and executed, an instruction decoder 7 outputs a control signal for selecting the binary arithmetic mode to a selecting circuit 5 and the correcting circuit 4 adds zero to the output of the binary arithmetic circuit 3, so that the binary arithmetic results of temporary registers 1 and 2 are outputted to a data bus 8. This is effective for all or specific arithmetic instructions until a microcode for changing the setting to the decimal arithmetic code is executed newly.


Inventors:
YOKOUCHI HIDEAKI
Application Number:
JP21294485A
Publication Date:
April 02, 1987
Filing Date:
September 26, 1985
Export Citation:
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Assignee:
SEIKO EPSON CORP
International Classes:
G06F7/50; G06F7/494; (IPC1-7): G06F7/50
Domestic Patent References:
JPS5649945B21981-11-26
JPS5380933A1978-07-17
JPS6065342A1985-04-15
Attorney, Agent or Firm:
Kisaburo Suzuki (1 outside)