Intel Corporation

Zenith Data Systems Corporation

Packard Bell Nec

Norman J Rasmussen

William S Wu

Bruce A Young

Peter D MacWilliams

Stephen Anthony Fischer

Suresh K Marisetty

Nicholas D Wade

Puthiya K Nizar

Jeffrey L Rabe

Dave Carson

Gary A Solomon

Thomas F Joyce

Darren L Abramson

Jian-Kuo Shen

Chester M Nibby, Jr

Michael J McTague

Brad W Hosler

Bruno DiPlacido, Jr

Jeffrey S Somers

Thomas L Murray, Jr

James F Bertone

Michelle A Pence

G Lewis Steiner

Lance J McNally

Martin Massucci

Marc Sanfacon

Brent S Baxter

George R Hayek

David G Carson

Charles B Guy

Colyn Case

Apparatus and methods to control an external bus. In one embodiment, an apparatus includes an external bus port and an external bus controller. The external bus controller can include a first register interface to receive a first set of data and a second register interface to receive a second set of data. The external bus controller can send the first set of data and the second set of data to said external bus port.

Apparatus and method for dedicated interconnection over a shared external bus

A high-throughput memory access interface allows higher data transfer rates between a system memory controller and video/graphics adapters than is possible using standard local bus architectures. The interface enables data to be written directly to a peripheral device at either one of two selectable speeds. The peripheral device may be a graphics adapter. A signal indicative of whether the adapter's write buffers are full is used to determine whether a write transaction to the adapter can proceed. If the transaction can not proceed at that time, it can be enqueued in the interface.

High-throughput interface between a system memory controller and a peripheral device

A high throughput memory access port is provided. The port includes features which provide higher data transfer rates between system memory and video/graphics or audio adapters than is possible using standard local bus architectures, such as PCI or ISA. The port allows memory read and write requests to be pipelined in order to hide the effects of memory access latency. In particular, the port allows bus transactions to be performed in either a non-pipelined mode, such as provided by PCI, or in a pipelined mode. In the pipelined mode, one or more additional memory access requests are permitted to be inserted between a first memory access request and its corresponding data transfer. In contrast, in the non-pipelined mode, an additional memory access request cannot be inserted between a first memory access request and its corresponding data transfer.

High-throughput interconnect having pipelined and non-pipelined bus transaction modes

High-throughput interface between a system memory controller and a

Memory bus extensions to a high speed peripheral bus are presented. Specifically, sideband signals are used to overlay advanced mechanisms for cache attribute mapping, cache consistency cycles, and dual processor support onto a high speed peripheral bus. In the case of cache attribute mapping, three cache memory attribute signals that have been supported in previous processors and caches are replaced by two cache attribute signals that maintain all the functionality of the three original signals. In the case of cache consistency cycles, advanced modes of operation are presented. These include support of fast writes, the discarding of write back data by a cache for full cache line writes, and read intervention that permits a cache to supply data in response to a memory read. In the case of dual processor support, several new signals and an associated protocol for support of dual processors are presented. Specific support falls into three areas: the extension of snooping to support multiple caches, the support of shared data between the two processors, and the provision of a processor and upgrade arbitration protocol that permits dual processors to share a single grant signal line.

Method and apparatus for sharing a signal line between agents

A symmetric multiprocessing system with a unified environment and distributed system functions provides unified address space for all functional units in the system while distributing the execution of various system functions over the functional units of the system whereby each functional unit assumes responsibility for its own aspects of these operations. In addition, the system provides improved system bus operation for transfer of data from memory.

Symmetric multiprocessing system with unified environment and

A method of arbitrating among bus agents, wherein a bus agent is permitted multiple transactions within a single arbitration cycle. An arbitration event is initiated, and a request from a bus agent is granted to that bus agent for executing a transaction. A timer is started and the transaction is executed. If the timer does not expire before the transaction is completed, another request from that same bus agent is granted to the bus agent for executing an additional transaction before a subsequent arbitration event is initiated.

Method and apparatus for executing multiple transactions within a single

A computer bus that enables bus mastering agents to send/receive a burst of data to/from a slave agent without determining in advance the number of data words to be transferred, or even the maximum number of data words that could be transferred. Either the master, the slave, or the bus arbiter can terminate the burst at any time with minimum overhead. Furthermore, either the master or the slave can throttle the speed of the data transfer by adding wait states. Distributed address decode is performed by each agent coupled to the bus. Each agent must claim a transaction directed toward it by the master. If no agent claims the transaction within a predetermined number of clock periods, a subtractive decode device may claim the transaction by default. The bus also includes a bus lock wherein each bus slave agent may be able to enter a locked state, and once in the locked state, reject all accesses except those initiated by the master agent that locked it. Signal line LOCK# is owned by only one master agent at a time. Although the LOCK# signal must be obtained by acquiring the bus while LOCK# is high, ownership of the line is maintained as long as LOCK# is held low. Therefore, a master agent can own the lock while another master uses the bus.

Locking protocol for peripheral component interconnect utilizing master

A bus bridge is disclosed that handles bus transactions that must be completed on a destination bus before being completed on an originating bus by indicating a retry to delay such bus transactions on the originating bus while completing such bus transactions on the destination bus.

Data consistency across a bus transactions that impose ordering

Method and apparartus for sharing a signal line between agents

Timing calculator means in a computer system are used to adaptively generate an appropriate access signal, to one of a plurality of memory types, based on first and second timing control values, wherein the first timing control value represents information specific to and limited to the start of a memory operation and wherein the second timing control value represents information representing other timing events. That is, the state machine of the present invention requires a distinct starting control value, separate from other timing values, for calculation of appropriate memory access parameters.

Adaptively generating timing signals for access to various memory

A bus with bus commands which optimize the management of buffers within a bus bridge is disclosed. The bus incorporates at least two types of write commands, a Postable Memory Write command and a Memory Write command. The Postable Memory Write command serves as a write command which additionally instructs the bus bridge that the processor will not be informed that the data transfer is complete, and thus, data may be posted in the bus bridge. In contrast, the Memory Write command serves as a write command which additionally instructs the bus bridge that the processor may be informed that the data transfer is complete, and that data should not, accordingly, be posted. These two write commands are used in combination such that a data transfer of a contiguous block of data utilizes Postable Memory Write commands until the final transaction in the transfer, at which time, a Memory Write command is used. The bus further incorporates at least two types of read commands, including a Memory Read Prefetch command and a Memory Read command. The Memory Read Pre-fetch command serves as a read command which additionally instructs the bus bridge to pre-fetch a first amount of data. The Memory Read command serves as a read command which additionally instructs the bridge to pre-fetch a second amount of data, or in an alternative usage, to read the data without pre-fetching.

Bus bridge for responding to received first write command by storing

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Hillsboro, OR, United States of America

Norman J Rasmussen