International Business Machines Corporation

J Adam Butts

Silvia Melitta Mueller

Stephen Victor Kosonocky

Harry S Barowski

Jochen Preiss

Viresh Paruthi

Maarten Jakob Boersma

Gary S Ditlow

Nicolas Maeding

Tobias Gemmeke

Brian Chan Monwai

The forcing of the result or output of a rounder portion of a floating point processor occurs only in a fraction non-increment data path within the rounder and not in the fraction increment data path within the rounder. The fraction forcing is active on a corner case such as a disabled overflow exception. A disabled overflow exception may be detected by inspecting the normalized exponent. If a disabled overflow exception is detected, the round mode is selected to execute only in the non-increment data path thereby preventing the fraction increment data path from being selected.

Efficient forcing of corner cases in a floating point rounder

The present invention provides a fully automatic method for obtaining a circuit having minimized power consumption due to clock-gating. A circuit design to be optimized is modified to a reduced power modified design and associated with a clock gating scheme. Verification tools compare the modified design with the original design to a predetermined trigger-events to determine if the modified design can be used. Further modifications may be made iteratively until an optimal design is achieved.

Formally deriving a minimal clock-gating scheme

A method for executing multiple computational primitives is provided in accordance with exemplary embodiments. A first computational unit and at least a second computational unit cooperate to execute multiple computational primitives. The first computational unit independently computes other computational primitives. By virtue of arbitration for shared source operand buses or shared result buses, availability of the first and second computational units needed to execute cooperatively the multiple computational primitives is assured by a process of reservation as used for a computational primitive executed on a dedicated computational unit.

Multiplexing output from second execution unit add/saturation processing portion of wider width intermediate result of first primitive execution unit for compound computation

A circuit incorporating a current starved ring oscillator is coupled to a power gate switch in an integrated circuit. The circuit incorporating the current starved ring oscillator amplifies a voltage difference between a virtual ground associated with the power gate switch and ground, and converts the difference to a frequency. Digital logic monitors the output of the ring oscillator using a counter and a reference clock. Control circuitry controls operation of the integrated circuit in dependence on the monitored conditions associated with the power gate switch. A method monitors a virtual ground voltage across a power gate switch in an integrated circuit; and controls operation of the integrated circuit in dependence on the monitored virtual ground voltage.

Methods and apparatus for monitoring power gating circuitry and for controlling circuit operations in dependence on monitored power gating conditions

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Hartsdale, NY, United States of America

J Adam Butts