Intel Corporation

Marvellworld Trade Ltd.

Jay S Heeb

Lawrence T Clark

Dennis M O'Connor

Sunil R Shenoy

Michael W Morrow

Bart R McDaniel

Byron R Gillespie

Elliot D Garbus

Thomas M Johnson

Gregory B Tucker

Mitchell A Kahn

Jimmy W Wong

Tom J Adelmeyer

Yuan-Po Ypt Tseng

Ali Minaei

Sehat Sutardja

Mark Norman Fullerton

Hong-Yi Chen

Premanand Sakarda

Stephen J Strazdus

Mark A Schaecher

Timothy J Jehl

Scott B Huck

Paul G Meyer

Thomas Adelmeyer

Rahul Shukla

Avery Topps

A core switching system includes a mode switching module that receives a switch signal to switch operation between a first mode and a second mode. During the first mode, instructions associated with applications are executed by a first asymmetric core, and a second asymmetric core is inactive. During the second mode, the instructions are executed by the second asymmetric core, and the first asymmetric core is inactive. A core activation module stops processing of the applications by the first asymmetric core after interrupts are disabled. A state transfer module transfers a state of the first asymmetric core to the second asymmetric core. The core activation module allows the second asymmetric core to resume execution of the instructions and the interrupts are enabled.

Dynamic core switching

Briefly, in accordance with one embodiment of the invention, an integrated circuit has a voltage regulator and a clock divider that may be used to adjust the operational frequency and/or voltage potential of the integrated circuit to reduce the power consumption of the integrated circuit while in operation.

Apparatus having adjustable operational modes and method therefore

Briefly, in accordance with one embodiment of the invention, a system includes: a processor, a voltage regulator, and a memory. The voltage regulator is coupled to the processor to adjust the operating voltage of the processor. The memory is coupled to the processor by a memory bus. The memory has stored on it processor instructions that, when executed by the processor, result in modification of the operating frequency of the processor and result in adjustment of the operating voltage of the processor, based, at least in part, on dynamic changes in the processing load of the processor.

Method and apparatus for dynamic power control of a low power processor

A pre-arbitrated bypassing system in a speculative execution microprocessor is provided. The bypassing system provides execution units enhanced to include a comparator and an enabled driver. The comparator compares a bypass address that is broadcast upon instruction decode with the destination address within each execution unit. If there is a match, then the result data is driven onto the bypass bus. Additionally, a suppress signal and validation scheme/apparatus are included to ensure that valid data is being driven onto the bypass bus. A bypass bus and associated apparatus may be included for every potential source operand.

Pre-arbitrated bypasssing in a speculative execution microprocessor

A processor for executing a set of instructions, where each instruction in said set of instructions includes a set of operand references. The processor includes an instruction decoder for extracting the set of operand references from each instruction in the set of instructions; a register file decoder connected to the instruction decoder for receiving the set of operand references and generating a set of register data select signals; and, a register file connected to the register file decoder for receiving the set of register data select signals. Further, the register file includes: a set of registers; a first set of scoreboard bits; and, a second set of scoreboard bits; wherein for each signal in the set of register data select signals, the register file outputs: (1) a corresponding register from the set of registers; (2) a first corresponding scoreboard bit from the first set of scoreboard bits; and, (3) a second corresponding scoreboard bit from the second set of scoreboard bits.

Method and apparatus for dynamic location and control of processor

A processor core suitable for use with a wide variety of instruction fetch units. The processor core contains a plurality of pipe stages including an instruction pointer generation stage and a decode stage. The core bundles all control necessary for downstream pipeline operation with an instruction address in a first stage. The bundle is transmitted outside the core to the instruction fetch unit. The instruction fetch unit fetches the instruction and adds it to the bundle, before forwarding the bundle as modified back within the core and down the pipeline. In this way, an external pipe stage is introduced providing a connection between discontinuous pipe stages in the core. Additionally, by bundling the control signals and address information in a single bundle that traverses the external pipe stage as a group, synchronization concerns are reduced or eliminated.

Method and apparatus permitting the use of a pipe stage having an

Pre-arbitrated bypassing in a speculative execution microprocessor

A method and apparatus for hit-dependent flushing of cacheable memory access operations in a bus controller queue is described. The present invention is implemented in the context of a computer system including a microprocessor coupled to an external memory device through an external bus. The processor includes a processor core for issuing memory access operations, a cache, and a bus controller. The bus controller includes a queue having slots for storing pending memory access operations to be sent out over the external bus. After a first memory access operation is issued, the bus controller stores the first memory access operation in a first queue slot before it is determined whether the first operation hits or misses the cache. The bus controller flushes the first operation from the queue if the first operation hits the cache. In response to the processor core issuing a second memory access operation, the bus controller stores the second memory access operation in the first queue slot if the first operation hits the cache. If, on the other hand, the first operation misses the cache, then the bus controller stores the second memory access operation in a second queue slot. Preferably, the first operation is issued in a first cycle and stored in the first queue slot in a second cycle that immediately follows the first cycle, and the second operation is issued in the second cycle.

Method and apparatus for pushing a cacheable memory access operation

A microprocessor and method which allows data consistency to be maintained between a memory which is external to the microprocessor and a data cache unit. The microprocessor has a central processing unit coupled to a local bus. A direct memory access unit coupled to the central processing unit for loading data from and storing data to the direct access memory unit. The local bus is coupled to a system bus and has a bus control unit controlling the loading and storing of data on the system bus. The system bus transfers data external to the microprocessor using the bus control unit upon instructions from the central processing unit. A data cache unit is coupled to the local bus and selectively stores a copy of data loaded by the bus control unit and receives a memory address from the local bus during a memory access by either the central processing unit or the direct memory access unit. The microprocessor employs a mechanism that invalidates copy data when the memory access is a store by the direct memory access unit when a cache hit is detected. Further, the microprocessor employs a mechanism that designates as non-cacheable the loading of data by the direct access memory unit, even though the data was previously designated as cachable, preventing the data cache unit from performing any action, namely the overwriting of more critical data within the data cache unit.

Method and apparatus for using a direct memory access unit and a data

The system and method described provide for the detection and protection of memory accesses without the overhead typically incurred by memory management units. The processor includes a guarded memory unit, which monitors memory accesses to be performed by monitoring transmissions across the memory bus. The guarded memory unit includes a plurality of registers which identify memory addresses and modes which can cause a memory protection or detection violation to occur. If a memory protection violation occurs, a cancel signal is issued to cancel the memory operation prior to completion in order to protect the memory from unauthorized accesses. If a memory violation is detected, the memory operation is permitted to complete and a fault signal is issued to the processor to identify that a memory violation has been detected. As the structure of the protection mechanism does not require separate cycles in the processor, and simply monitors the memory bus for memory accesses, memory protection and detection can be performed with no additional overhead at the processor.

System for protecting memory accesses by comparing the upper and lower

A dynamically expandable pipeline in a microprocessor. The present invention is used in a microprocessor or a microprocessor in a computer system. The present invention delays execution of a cacheable LOAD instruction by a bus controller for one cycle to allow sufficient time for 'hit or miss' detection by a data cache unit. The present invention dynamically expands the instruction pipeline for cacheable LOAD instructions that 'miss' an on-chip data cache when the LOAD is followed by another instruction that uses the bus controller. The dynamic pipeline allows time for the 'hit or miss' detection by the data cache unit without unnecessarily degrading pipeline performance. The present invention offers increased overall microprocessor and computer system performance by allowing efficient implementation of an on-chip data cache. The present invention provides increased performance without undue or overly complex modifications to existing pipeline or data cache circuits.

Method and apparatus for dynamically expanding the pipeline of a

A method and apparatus for performing bi-endian byte and short accesses in a single endian microprocessor. The present invention is used in a microprocessor or in a microprocessor in a computer system. The present invention provides a single endian microprocessor that promotes sub-word accesses to word accesses with a means for manipulating the two least significant bits of the access address to point to the correct sub-word data returned during an access to bi-endian external memory. The method for manipulating the address bits is also used to allow a single endian data cache to operate with the bi-endian external memory. The two LSBs of the address are manipulated such that the pointer values are A1# and A0# for word promoted byte accesses or cacheable accesses. For word promoted short accesses or cacheable accesses, the pointer values are A1# and A0. The present invention offers increased flexibility in interfacing a single-endian microprocessor with bi-endian systems. The present invention provides easy interfacing without undue or overly complex modifications to existing circuits.

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Gilbert, AZ, United States of America

Jay S Heeb