Abstract: A processor includes a physical register file having physical registers and an execution unit to perform an arithmetic operation to generate a result mapped to a physical register, wherein the processor delays a write of the result to the physical register file until the result is qualified as valid. A method includes mapping the same physical register both to store load data of a load-execute operation and to subsequently store a result of an arithmetic operation of the load-execute operation, and writing the load data into the physical register. The method further includes, in a first clock cycle, executing the arithmetic operation to generate the result, and, in a second clock cycle, providing the result as a source operand for a dependent operation. The method includes, in a third clock cycle, enabling a write of the result to the physical register file responsive to the result qualifying as valid.

Abstract: A processor includes a physical register file having physical registers and an execution unit to perform an arithmetic operation to generate a result mapped to a physical register, wherein the processor delays a write of the result to the physical register file until the result is qualified as valid. A method includes mapping the same physical register both to store load data of a load-execute operation and to subsequently store a result of an arithmetic operation of the load-execute operation, and writing the load data into the physical register. The method further includes, in a first clock cycle, executing the arithmetic operation to generate the result, and, in a second clock cycle, providing the result as a source operand for a dependent operation. The method includes, in a third clock cycle, enabling a write of the result to the physical register file responsive to the result qualifying as valid.

Abstract: Methods and apparatuses are provided for increased efficiency and enhanced power saving in a processor via scalar code optimization. The method comprises determining that an instruction comprises a scalar instruction and then processing the instruction using only a lower portion of an XMM register. The apparatus comprises an operational unit capable of determining whether an instruction comprises a scalar instruction and execution units responsive that determining for processing the scalar instruction using only a lower portion of an XMM register of the processor. By not processing the upper portion of the XMM register efficiency is increased and power saving is enhanced.

Abstract: A method and mechanism for reducing latency of a multi-cycle scheduler within a processor. A processor comprises a front end pipeline that determines data dependencies between instructions prior to a scheduling pipe stage. For each data dependency, a distance value is determined based on a number of instructions a younger dependent instruction is located from a corresponding older (in program order) instruction. When the younger dependent instruction is allocated an entry in a multi-cycle scheduler, this distance value may be used to locate an entry storing the older instruction in the scheduler. When the older instruction is picked for issue, the younger dependent instruction is marked as pre-picked. In an immediately subsequent clock cycle, the younger dependent instruction may be picked for issue, thereby reducing the latency of the multi-cycle scheduler.

Abstract: A decision tree, representing a knowledge base, is segmented into at least two decision tree portions. The lower portion includes the tree entry point and is stored in a memory element with a faster access time than the upper portion, which includes the terminating element of the decision tree. Thus during the process of reading the tree entries for comparing them with the search object, the search entries in the lower portion of the tree can be read faster than the search entries in the upper portion, resulting in a faster traversal through the entire decision tree.

Abstract: A network processor or other type of processor includes in an illustrative embodiment a first pass classifier coupled to first memory circuitry in the form of a relatively small internal memory, and a second pass classifier coupled to second memory circuitry in the form of a larger internal buffer memory. The first memory circuitry is configurable to store at least a portion of a given packet to be processed by the first pass classifier. The second memory circuitry is configurable to store a different and preferably smaller portion of the given packet to permit processing thereof by the second pass classifier. The portion of the given packet storable in the second memory circuitry is a portion of the given packet determined by a first pass classification, performed by the first pass classifier, to be required for a second pass classification, performed by the second pass classifier.

Abstract: A network processor or other type of processor includes classification circuitry and memory circuitry coupled to the classification circuitry. The memory circuitry is configured to store at least a portion of at least a given one of a number of packets to be processed by the classification circuitry. The classification circuitry implements a non-sequential packet classification process for at least a subset of the packets including the given packet. For example, in an embodiment in which the given packet is generated in accordance with multiple embedded protocols, the non-sequential packet classification process allows the processor to return from a given point within the packet, at which a final one of the protocols is identified, to a beginning of the packet, through the use of a “skip to beginning” instruction. The skip to beginning instruction may be configured to allow the processor to skip back to a particular bit, e.g.

Abstract: A network processor or other type of processor includes first classification circuitry, scheduling circuitry and second classification circuitry. The first classification circuitry is configured to determine for a given packet received by the processor whether the packet has one or more errors. The scheduling circuitry in an illustrative embodiment receives an indication of the error determination made by the first classification circuitry, and based on the indication controls the dropping of the given packet from the processor memories if the packet has one or more errors, e.g., via a flush transmit command. The second classification circuitry, which may be implemented as a single classification engine or a set of such engines, may be configured to perform at least one classification operation for the given packet, e.g., if the packet is supplied thereto by the scheduling circuitry.

Abstract: A network processor or other type of processor includes classification circuitry and memory circuitry coupled to the classification circuitry. The memory circuitry is configured to store at least a portion of at least a given one of a number of packets to be processed by the classification circuitry. The classification circuitry implements a non-sequential packet classification process for at least a subset of the packets including the given packet. For example, in an embodiment in which the given packet is generated in accordance with multiple embedded protocols, the non-sequential packet classification process allows the processor to return from a given point within the packet, at which a final one of the protocols is identified, to a beginning of the packet, through the use of a “skip to beginning” instruction. The skip to beginning instruction may be configured to allow the processor to skip back to a particular bit, e.g.

Abstract: A network processor or other type of processor includes in an illustrative embodiment a first pass classifier coupled to first memory circuitry in the form of a relatively small internal memory, and a second pass classifier coupled to second memory circuitry in the form of a larger internal buffer memory. The first memory circuitry is configurable to store at least a portion of a given packet to be processed by the first pass classifier. The second memory circuitry is configurable to store a different and preferably smaller portion of the given packet to permit processing thereof by the second pass classifier. The portion of the given packet storable in the second memory circuitry is a portion of the given packet determined by a first pass classification, performed by the first pass classifier, to be required for a second pass classification, performed by the second pass classifier.

Abstract: A network processor or other type of processor includes first classification circuitry, scheduling circuitry and second classification circuitry. The first classification circuitry is configured to determine for a given packet received by the processor whether the packet has one or more errors. The scheduling circuitry in an illustrative embodiment receives an indication of the error determination made by the first classification circuitry, and based on the indication controls the dropping of the given packet from the processor memories if the packet has one or more errors, e.g., via a flush transmit command. The second classification circuitry, which may be implemented as a single classification engine or a set of such engines, may be configured to perform at least one classification operation for the given packet, e.g., if the packet is supplied thereto by the scheduling circuitry.

Abstract: A decision tree, representing a knowledge base, is segmented into at least two decision tree portions. The lower portion includes the tree entry point and is stored in a memory element with a faster access time than the upper portion, which includes the terminating element of the decision tree. Thus during the process of reading the tree entries for comparing them with the search object, the search entries in the lower portion of the tree can be read faster than the search entries in the upper portion, resulting in a faster traversal through the entire decision tree.