The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 14, 1990
Filed:
Oct. 21, 1988
Junichi Iwasaki, Tokyo, JP;
Shingo Kojima, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A microcomputer system includes a master processor and a coprocessor interconnected via a bus. The coprocessor supplies first, second and third signals to the master process, the first (BUSY) signal taking an active level when the coprocessor requests a wait condition of the master processor, the second (CPERR) signal taking an active level at least when the first signal is changed to the inactive level in a state of occurrence of an arithmetic exception in the coprocessor, and the third (CPEND) signal taking an active level when the coprocessor is free of execution of an instruction and of an occurrence of an arithmetic exception. When the coprocessor executes an instruction whose execution result is not required to be returned to the master processor, the master processor detects the level of the third signal and if the third signal is at the active level, the master processor starts to execute subsequent instructions irrespective of the first and second signals, in parallel with the execution of the instruction by the coprocessor.