Apple Inc.

Edvin Catovic

Shingo Suzuki

Rajat Goel

Pradeep Kanapathipillai

Richard F Russo

Harsha Krishnamurthy

Boris S Alvarez-Heredia

Matthew R Johnson

Raghava Rao V Denduluri

Manoj Gopalan

Pankaj Lnu

A processor includes an instruction issue circuit, and high-utilization and low-utilization execution unit circuits coupled to execute instructions received from the instruction issue unit. On average, utilization of the low-utilization execution unit circuit is lower than utilization of the high-utilization execution unit circuit. The processor also includes a retention circuit coupled to a different power domain than the low-utilization execution unit circuit, and a power management circuit. The power management circuit may be configured to detect that inactivity of the low-utilization execution unit circuit satisfies a threshold inactivity level; upon detecting that the threshold inactivity level is satisfied, cause architecturally-visible state of the low-utilization execution unit circuit to be copied to the retention circuit; and subsequent to copying of the architecturally-visible state to the retention circuit, cause the low-utilization execution unit circuit to enter a power-off state, where the retention circuit retains stored data during the power-off state.

Execution unit power management

Embodiments of a multiplier unit that may be used for division and square root operations are disclosed. The embodiments may provide a reduced and fixed latency for denormalization and rounding used in the division and square root operations. A storage circuit may be configured to receive first and second source operands. A multiplier circuit may be configured to perform a plurality of multiplication operations dependent upon the first and second source operands. Each result after an initial result of the multiplier may also depend on at least one previous result. Circuitry may be configured to perform a shift operation and a rounding operation on a given result of the plurality of results. An error of the given result may be less than a predetermined threshold value.

Multiplier unit with speculative rounding for use with division and square-root operations

In an embodiment, an integrated circuit may include one or more power gated blocks and a power manager circuit. The power manager circuit may be configured to generate a block enable for each power gated block and a block enable clock. The power gated block may generate local block enables to various power switch segments in the power gated block. In particular, the power gated block may include a set of series-connected flops that receive the block enable from the power manager circuit. The power gated block may include a set of multiplexors (muxes) that provide the local block enables for each power switch segment. One input of the muxes is coupled to the block enable, and the other input is coupled to another enable propagated through one of the other power switch segments. Accordingly, the muxes may be controlled to select the propagated enables or the input block enable.

Power switch ramp rate control using selectable daisy-chained connection of enable to power switches or daisy-chained flops providing enables

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San Francisco, CA, United States of America

Edvin Catovic