Abstract: A traffic control system and method with flow control aggregation. The system includes a switching fabric and an ingress module. The switching fabric includes read counters that are associated with a plurality of queues. The read counters represent an aggregated number of cells dequeued from respective queues since a previous flow control message (FCM) was sent to the ingress module. The read counters are reset when a FCM is created. The ingress module includes write counters that are associated with the queues. The write counters are incremented each time a cell is sent to the respective queues. The write counters are decremented in accordance with the FCM when the FCM is received. Also, read counters for one or more queues are aggregated into a single FCM.

Abstract: A network flow controller to manage network traffic bandwidth is described. Embodiments of the network flow controller include a hierarchical flow creditor, a proportional flow creditor, and a rate limiter. The hierarchical flow creditor is configured to manage a plurality of hierarchical credit accounts. The hierarchical credit accounts include a shared credit account associated with a plurality of distinct network traffic flows for a shared bandwidth resource. The proportional flow creditor is configured to track an oversubscription of the shared bandwidth resource by the plurality of distinct network traffic flows. The rate limiter is coupled to the hierarchical flow creditor and the proportional flow creditor. The rate limiter is configured to limit at least one of the distinct network traffic flows based on the oversubscription tracked by the proportional flow creditor.

Abstract: A system for efficiently reassembling packets from cells received on independent switching fabrics according to a serial high speed interface (HSI) protocol. The system includes redundancy in that fabrics may be removed by skipping the fabrics in striping and reassembly sequences. When fabrics are added, the fabrics are included in the striping and reassembly sequences. The system is efficient due in part to in-order transmission of cells serially across multiple fabrics. Full fabric bandwidth is thereby utilized without reordering overhead. Since packets are striped across all available fabrics, load is balanced across the fabrics.

Abstract: A system for efficiently sending cells in-order to independent switching fabrics according to a serial high speed interface (HSI) protocol. The system includes redundancy in that fabrics may be removed by deleting the fabrics from striping and reassembly sequences. When fabrics are added, the fabrics are added to the striping and reassembly sequences. The system is efficient due in part to in-order transmission of cells serially across multiple fabrics. Full fabric bandwidth is thereby utilized without reordering overhead. Since packets are striped across all available fabrics, load is balanced across the fabrics.

Abstract: The present invention relates to the design of highly reliable high performance microprocessors, and more specifically to designs using a blind invalidate circuit in high-speed memories. In accordance with an embodiment of the present invention, a tag array memory circuit including a plurality of memory bit circuits coupled together to form an n-bit memory cell; and a blind invalidate circuit coupled to a memory bit circuit in the n-bit memory cell, the blind invalidate circuit to clear a bit in the memory bit circuit, if a primary clear bit line is asserted and a received bit value of a right-adjacent memory bit circuit is zero.

Abstract: A method is provided for requesting data from a memory. The method includes issuing a plurality of data requests to a data request port for the memory. The plurality of data requests includes at least two ordered data requests. The method includes determining if an earlier one of the ordered data requests corresponds to a miss in the memory, and converting a later one of the ordered data requests to a prefetch in response to the earlier one of the ordered data requests corresponding to a miss in the memory. An apparatus includes a memory having at least one pipelined port for receiving data requests. The port is adapted to determine whether an earlier ordered one of the data requests corresponds to a miss in the memory. The port converts a later ordered one of the data requests to a prefetch in response to determining that the earlier ordered one of the data requests corresponds to a miss in the memory.

Abstract: A packet-based traffic switching system with error detection and correction without taking the system offline. The system tests offline paths without interfering with other online paths. Also, the system tests online paths even while no data cell traffic is sent over the paths. The system responds to the addition or removal of paths or path components without interrupting cell traffic. The system detects and selectively flushes defective paths without impacting paths that are working properly. The system initializes new switching fabrics automatically without using software to set values. Thus, the system tests online paths and corrects errors without going offline.

Abstract: An apparatus and method to provide ordering when an advanced load address table is used for advanced loads. An advanced load address table (ALAT) is used to retain an entry associated with a location accessed by an advanced load instruction. The entry is utilized to determine if an intervening access to the location is performed by another instruction prior to the execution of a corresponding checking instruction. Ordering is maintained to ensure validity of the entry in the ALAT, when the advanced load instruction is boosted past an ordering setting boundary.

Abstract: An apparatus and method for reducing power consumption in a processor front end are provided. The processor includes an instruction cache, a TLB, and a branch predictor. For sequential code execution, the instruction cache is disabled unless the next instruction fetch will cross a cache line boundary, thus reducing unnecessary accesses to the instruction cache. The TLB is disabled unless the next instruction fetch will cross a page boundary, thus reducing unnecessary TLB look-ups. For code branching, the branch predictor is configured to include, for each target address, an indication of whether the target address is in the same page as the corresponding branch address. When a branch occurs so as to cause access to a given entry in the branch predictor, the TLB is disabled if the target address is in the same page as the branch address.

Abstract: A prime number based pointer allocation technique. A packet-forwarding system incorporating the technique stores cells of a packet in packet memory, according to allocated pointers that have a fixed correspondence to locations in the packet memory. Each packet input interface of an ingress module has a memory parameter counter that is incremented by a different prime number each time a memory pointer is allocated to that input interface. The memory parameter counter includes a memory interface portion and a memory bank portion that correspond to the memory interfaces and memory banks of a packet memory with which the memory pointers are associated.

Abstract: A traffic control system and method with flow control aggregation. The system includes a switching fabric and an ingress module. The switching fabric includes read counters that are associated with a plurality of queues. The read counters represent an aggregated number of cells dequeued from respective queues since a previous flow control message (FCM) was sent to the ingress module. The read counters are reset when a FCM is created. The ingress module includes write counters that are associated with the queues. The write counters are incremented each time a cell is sent to the respective queues. The write counters are decremented in accordance with the FCM when the FCM is received. Also, read counters for one or more queues are aggregated into a single FCM.

Abstract: A system for efficiently reassembling packets from cells received on independent switching fabrics according to a serial high speed interface (HSI) protocol. The system includes redundancy in that fabrics may be removed by skipping the fabrics in striping and reassembly sequences. When fabrics are added, the fabrics are included in the striping and reassembly sequences. The system is efficient due in part to in-order transmission of cells serially across multiple fabrics. Full fabric bandwidth is thereby utilized without reordering overhead. Since packets are striped across all available fabrics, load is balanced across the fabrics.

Abstract: A system for efficiently sending cells in-order to independent switching fabrics according to a serial high speed interface (HSI) protocol. The system includes redundancy in that fabrics may be removed by deleting the fabrics from striping and reassembly sequences. When fabrics are added, the fabrics are added to the striping and reassembly sequences. The system is efficient due in part to in-order transmission of cells serially across multiple fabrics. Full fabric bandwidth is thereby utilized without reordering overhead. Since packets are striped across all available fabrics, load is balanced across the fabrics.

Abstract: A translation buffer is described which can translate virtual addresses to physical addresses wherein the virtual addresses have varying page sizes. The translation buffer includes a decoder to generate a hashed index, the index identifying an entry into two arrays. The first of the two arrays identifies a corresponding physical page address and the other array identifies a corresponding variable page address that in comparison to a variable portion of the virtual address, will indicate whether the entry in the first array has a matching entry. If the first array identifies a matching physical page address, then the physical page address is combined with the offset of the virtual address to yield a physical address translation of the virtual address.

Abstract: A translation buffer is described which can translate virtual addresses to physical addresses wherein the virtual addresses have varying page sizes. The translation buffer includes a decoder to generate a hashed index, the index identifying an entry into two arrays. The first of the two arrays identifies a corresponding physical page address and the other array identifies a corresponding variable page address that in comparison to a variable portion of the virtual address, will indicate whether the entry in the first array has a matching entry. If the first array identifies a matching physical page address, then the physical page address is combined with the offset of the virtual address to yield a physical address translation of the virtual address.

Abstract: An apparatus includes a plurality of error detection circuits. Each of the plurality of error detection circuits is coupled to one of a like plurality of ways in a set associative cache memory to receive a tag word and an error detection flag from the coupled way. Each of the plurality of error detection circuits generates a way error signal that is asserted if an error is detected in the tag word of the coupled way. A logical OR circuit is coupled to the plurality of error detection circuits to receive the plurality of way error signals. The logical OR circuit generates a tag error signal that is asserted if at least one of the plurality of way error signals is asserted.

Abstract: A prevalidation content addressable memory, CAM, is used to pre-decode a virtual address region extension and enable it for use by a translation look-aside buffer, TLB. The prevalidation CAM removes the region extensions stored in region registers from a serial TLB look-up path.

Abstract: A method is provided for managing temporal and non-temporal data in the same cache structure. The temporal or non-temporal character of data targeted by a cache access is determined, and a cache entry for the data is identified. When the targeted data is temporal, a replacement priority indicator associated with the identified cache entry is updated to reflect the access. When the targeted data is non temporal, the replacement priority indicator associated with the identified cache entry is preserved. The method may also be implemented by employing a first algorithm to update the replacement priority indicator for temporal data and a second, different algorithm to update the replacement priority indicator for non-temporal data.

Abstract: A novel on-chip cache memory and method of operation are provided which increase microprocessor performance. The cache design allows two cache requests to be processed simultaneously (dual-ported) and concurrent cache requests to be in-flight (pipelined). The design of the cache allocates a first clock cycle to cache tag and data access and a second cycle is allocated to data manipulation. The memory array circuit design is simplified because the circuits are synchronized to the main processor clock and do not need to use self-timed circuits. The overall logic control scheme is simplified because distinct cycles are allocated to the cache functions.

Abstract: A fully-associative translation lookaside buffer structure for a computer system includes a first-level TLB0 memory having a plurality of entries and a second-level TLB1 memory operatively coupled to the first level TLB0 memory. The second-level TLB1 memory also has a plurality of entries. Entries are placed in the TLB0 and TLB1 structure as a result of software controlled translation register operations and hardware controlled translation cache operations. Logic controlling TLB0 treats both operations the same way and uses a hardware replacement algorithm to determine the entry index. Logic controlling TLB1 uses a hardware replacement algorithm to determine the entry index for translation cache entries, and use an index provided within the insertion instruction to determine the entry index for translation register operations.