International Business Machines Corporation

Motorola Corporation

Cisco Technology, Inc.

Aubrey Deene Ogden

James Allan Kahle

Chin-Cheng Kau

Albert J Loper, Jr

Soummya Mallick

Donald E Waldecker

John Victor Sell

Ali A Poursepanj

David S Levitan

Gianfranco Gerosa

Michael C Alexander

Alexander Dankwart Essbaum

Arturo L Arizpe

Paul Kang-Guo Tu

Michael Putrino

Neil R Vanderschaaf

Tai Dinh Ngo

Anita S Grossman

Paul K-g Tu

Johm Victor Sell

Gregory L Limes

Mason L Weems

A router coupled to a plurality of networks receives a data packet from a first one of the networks and routes the data packet to a second one of the networks. The data packet includes a first portion having a destination network address. The router receives a first portion of the data packet, and the first portion of the data packet includes a destination network address. The destination network address of the data packet is asserted to a content addressable memory (&ldquo;CAM&rdquo;), where the CAM has stored routing information, while the first packet is not yet fully received from the first network. The CAM identifies one of the networks coupled to the router, in response to the destination network address being in the CAM, while the router is still receiving a remaining portion of the data packet. After identification of the destination network the data packet is routed to the destination network. However, in response to the destination network address not being in the CAM, the data packet is received completely, and a database searched for the destination network address, and the data packet is forwarded after the destination address is found in the database. The destination address may then be written into the CAM.

Method and apparatus for message routing, including a content addressable memory

In a router coupled to a number of networks, a data packet is received from a first one of the networks and routed to a second one of the networks. The data packet includes a first portion having a destination network address. The destination network address for the data packet is input to a content addressable memory (&ldquo;CAM&rdquo;) while the router is still receiving at least a portion of the data packet, so that the CAM, having network address information stored therein, identifies one of the networks coupled to the router and corresponding to the destination address of the data packet while the router is still receiving at least a portion of the data packet.

A method and system for increased instruction dispatch efficiency in a superscalar processor system having an instruction queue for receiving a group of instructions in an application specified sequential order and an instruction dispatch unit for dispatching instructions from an associated instruction buffer to multiple execution units on an opportunistic basis. The dispatch status of instructions within the associated instruction buffer is periodically determined and, in response to a dispatch of the instructions at the beginning of the instruction buffer, the remaining instructions are shifted within the instruction buffer in the application specified sequential order and a partial group of instructions are loaded into the instruction buffer from the instruction queue utilizing a selectively controlled multiplex circuit. In this manner additional instructions may be dispatched to available execution units without requiring a previous group of instructions to be dispatched completely.

Method and system for increased instruction dispatch efficiency in a

A method and system for permitting single cycle instruction dispatch in a superscalar processor system which dispatches multiple instructions simultaneously to a group of execution units for execution and placement of results thereof within specified general purpose registers. Each instruction generally includes at least one source operand and one destination operand. A plurality of intermediate storage buffers are provided and each time an instruction is dispatched to an available execution unit, a particular one of the intermediate storage buffers is assigned to any destination operand within the dispatched instruction, permitting the instruction to be dispatched within a single cycle by eliminating any requirement for determining and selecting the specified general purpose register or a designated alternate general purpose register.

Method and system for enhanced instruction dispatch in a superscalar

A method and device of executing a load multiple instruction in a superscaler microprocessor is provided. The method comprises the steps of dispatching a load multiple instruction to a load/store unit, wherein the load/store unit begins execution of a dispatched load multiple instruction, and wherein the load multiple instruction loads data from memory into a plurality of registers. The method further includes the step of maintaining a table that lists each register of the plurality of registers and that indicates when data has been loaded into each register by the executing load multiple instruction. The method concludes by executing an instruction that is dependent upon source operand data loaded by the load multiple instruction into a register of the plurality of registers indicated by the instruction as a source register, prior to the load multiple instruction completing its execution, when the table indicates the source operand data has been loaded into the source register. Also, according to the present invention, a method of executing a store multiple instruction in a superscaler microprocessor is provided. This method comprises the steps of dispatching a store multiple instruction to a load/store unit, whereupon the load/store unit begins executing the store multiple instruction, wherein the load store instruction stores data from a plurality of registers to memory; and executing a fixed point instruction that is dependent upon data being stored by the store multiple instruction from a register of the plurality of registers indicated by the fixed point instruction as a source register, prior to the store multiple instruction completing its execution, but prohibiting the executing fixed point instruction from writing to a register of the plurality of registers prior to the store multiple instruction completing.

Method and processor that permit concurrent execution of a store

A method and system for enhanced system management operations in a superscalar data processing system. Those supervisory level instructions which execute selected privileged operations within protected memory space are first identified as not requiring a full context synchronization. Each time execution of such an instruction is initiated an enable special access (ESA) instruction is executed as an entry point to that instruction or group of instructions. A portion of the machine state register for the data processing system is stored and the machine state register is then modified as follows: a problem bit is set, changing the execution privilege state to 'supervisor;' external interrupts are disabled; and access privilege state bit is set; and, a special access mode bit is set, allowing execution of special instructions. The instructions which execute the selected privileged operations within the protected memory space are then executed. A disable special access (DSA) instruction is then executed which restores the bits within the machine state register which were modified during the ESA instruction. The ESA and DSA instructions are implemented without modifying the instruction stream by utilizing user level procedure calls, thereby reducing the overhead of the branch table necessary to determine the desired execution path.

Method and system for enhanced management operation utilizing intermixed

The method and system of the present invention permits enhanced instruction dispatch efficiency in a superscalar processor system capable of fetching an application specified ordered sequence of scalar instructions and simultaneously dispatching a group of the scalar instructions to a plurality of execution units on a nonsequential opportunistic basis. A group of scalar instructions fetched in an application specified ordered sequence on a nonsequential opportunistic basis is processed in the present invention. The present invention detects conditions requiring serialization during the processing. In response to a detection of a condition requiring serialization, processing of particular scalar instructions from the group of scalar instructions are selectively controlled, wherein at least a portion of the scalar instructions within the group of scalar instructions are thereafter processed in a serial fashion.

Method and system for selective serialization of instruction processing

A method and system for permitting the selective support of non-architected instructions within a superscalar processor system. A special access bit within the system machine state register is provided and set in response to each initiation of an application during which execution of non-architected instructions is desired. Thereafter, each time a non-architected instruction is decoded the status of the special access bit is determined. The non-architected instruction is executed in response to a set state of the special access bit. The illegal instruction program interrupt is issued in response to an attempted execution of a non-architected instruction if the special access bit is not set. In this manner, for example, complex instruction set computing (CISC) instructions may be selectively enabled for execution within a reduced instruction set computing (RISC) data processing system while maintaining full architectural compliance with the reduced instruction set computing (RISC) instructions.

Method and system for selective support of non-architected instructions

A single-precision floating-point register array for a floating-point execution unit that performs double-precision operations by emulation is provided. The register array comprises a plurality of single-precision floating-point registers and a storage device that stores one or more status bits in association with each of the plurality of registers; the status bits associated with each register indicate either that the associated data register contains single-precision or integer data, or that the data for the associated register is contained in an emulated register in memory that is mapped to the associated register. When a register is a source for an operation, the status bits associated with the register are checked and the required operand data for that register is read from the register or from an emulated register mapped to that register, as a function of the state of the status bits.

Single-precision, floating-point register array for floating-point units

A method and system for efficient memory management in a data processing system which utilizes a memory management unit to translate effective addresses into real addresses within a translation lookaside buffer is disclosed. During a first mode of operation a selected number of effective address identifiers are stored in the translation lookaside buffer. In association with each virtual address identifier is a corresponding real address entry for a single memory block wherein selected virtual addresses may be translated into corresponding real addresses utilizing the translation lookaside buffer. In a second mode of operation, a selected number of virtual address identifiers are stored in a translation lookaside buffer and each virtual address identifier has a number of protection bits stored in association therewith, wherein each protection bit is indicative of a protection status for a large number of contiguous memory blocks beginning with the associated virtual address identifier, wherein memory block protection may be provided for a large number of memory blocks utilizing a fixed size translation lookaside buffer.

Method and system for efficient memory management in a data processing

Method and device for early deallocation of resources during load/store

A processing system and method of operation are provided. At least one execution unit processes information of a register in response to an instruction specifying the register. Each of multiple control units selectively allocates a respective one of multiple buffers to store the information in response to the instruction.

Method and system for storing information in a processing system

A method and circuitry are provided, in which a first operation is performed with first circuitry. A second operation is performed with second circuitry. A first signal is generated in response to the first operation. A second signal is generated in response to the second operation. Power consumption is adjusted within the second circuitry in response to the first and second signals.

Circuitry and method for reducing power consumption within an electronic

A method and system for enhanced instruction dispatch efficiency in a superscalar processor system having a plurality of intermediate storage buffers, a plurality of general purpose registers, and a storage buffer index. Multiple scalar instructions may be simultaneously dispatched from a dispatch buffer to a plurality of execution units. Each of the multiple scalar instructions generally include at least one source operand and one destination operand. A particular one of the plurality of intermediate storage buffers is assigned to a destination operand within a selected one of the multiple scalar instructions. A relationship between the particular one of the plurality of intermediate storage buffers and a designated one of the plurality of general purpose registers is stored in the storage buffer index at that time when the instruction which has been dispatched is replaced in the dispatcher by another instruction in the application program sequence. Results of execution from the selected one of the multiple scalar instructions are stored in the particular one of the intermediate storage buffers when the selected instruction is executed. The storage buffer index is used to determine which storage buffers to use as source operands for those instructions which are dispatched between the time that a storage buffer has been assigned for a specific general purpose register and the results of execution are moved from the storage buffer into the general purpose register.

Growing community of inventors

Round Rock, TX, United States of America

Aubrey Deene Ogden