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.

Date of Patent:
Sep. 02, 1997

Filed:

Sep. 16, 1994
Applicant:
Inventors:

Johannes Wang, Redwood City, CA (US);

Ata R Khan, Saratoga, CA (US);

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
395500 ; 364D / ; 36493362 ; 711156 ;
Abstract

A microcontroller routs bits of a PSW to and from a bus depending on a mode. Whenever in a mode compatible with a prior generation microcontroller, address and routing circuitry using decoders and multiplexers, during a read operation, places bits of the PSW of the current generation on the bus at a location of the prior generation microcontroller. In a write operator circuitry also moves bits from the bus in an arrangement compatible with the prior generation and stores them in the arrangement of the current generation. The circuitry also allows various units such as the ALU to update the PSW register bits directly without making a bus transfer.


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