Sun Microsystems, Inc.

Advanced Micro Devices Corporation

Harry R Fair

Matthew E Becker

Dwight K Elvey

Joseph R Siegel

Marc E Lamere

Kevin M Gillespie

Michael D Estlick

David R Akeson

Jonathan A White

A fault tolerant scannable glitch latch for use with scan chains that enable reset, debug and repairability of machines and parts is described. A scan shift enable signal controls a switch such that a stuck-at zero fault on a data input line is prevented from driving voltage to a state node or pulling the state node high during a scan chain operation. Propagation of the stuck-at zero fault is therefore eliminated. The scan shift enable signal also controls a switch that enables a parallel path to ground for the scan data and state node which would otherwise have been driven high due to the stuck-at zero fault.

Fault tolerant scannable glitch latch

A method of performing a fast information compare within a processor which includes performing a more significant bit compare when information is loaded into a translation lookaside buffer, storing a result of the more significant bit compare within the translation lookaside buffer as part of an entry containing the information, and using the result of the more significant bit compare in conjunction with results from a compare of less significant bits of the information and less significant bits of compare information to determine whether a match is present. The more significant bit compare compares more significant bits of the information being loaded into the translation lookaside buffer with more significant bits of compare information.

Partial address compares stored in translation lookaside buffer

Methods and systems for improving a logic circuit are described. By using a voltage reducer for connecting a power-supply to a virtual ground, the voltage reducer reduces the voltage supplied by the power-supply to the virtual ground during one phase of the clock, thereby increasing the speed and efficiency of the logic circuit.

Virtual ground circuit

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Harry R Fair