Matthew A Carlson

Address:

3417 Foothill Ter, Austin, TX 78731

VIN:

JTEBU11F570047374

Make:

TOYOTA

Model:

FJ CRUISER

Year:

2007

US Patent:

58928979, Apr 6, 1999

Filed:

Feb 5, 1997

Appl. No.:

8/795581

Inventors:

Matthew L. Carlson - Kyle TX
Bruce A. Parker - Austin TX

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

G06F 1100

US Classification:

39518313

Abstract:

A trailer microprocessor in a debugging tool runs code a known number of cycles behind a master and shadow pair of processors. A pipeline queues up bus activity from the shadow processor a number of cycles, and then outputs those signals to the trailer microprocessor to execute the same code and signals as the master and shadow microprocessors a known number of cycles behind. The outputs of the master and shadow microprocessors are compared and the trailer microprocessor is halted, along with the master and shadow, when a "mismatch" occurs between the outputs of the master and shadow processors. When the internal states of all three processors are scanned, the differences in the internal state of the shadow processor before and at a failure can be theoretically compared. The trailer microprocessor may be stepped cycle-by-cycle up to and past the point of failure of the shadow processor for further analysis.