Abstract: Real-time performance monitoring facility in an integrated circuit (IC) data processor for monitoring events related to different bus activity. The monitoring facility is accessible via a bus connection the IC. Events include device acquisition and ownership time, and the number of requests and grants on a given bus. The events are counted as occurrences and durations by a number of event counters integrated in the IC. The IC can notify software when the counters overflow. The IC may feature multiple clock domains, including, for instance, multiple bus interfaces operating at different clock frequencies, in which events from different clock domains may be tracked by the same counter. In one embodiment, the performance monitoring facility is integrated into an I/O processor (IOP) die that complies with the popular intelligent I/O (I2O) and Peripheral Components Interconnect (PCI) specifications.

Abstract: Real-time performance monitoring facility in an integrated circuit (IC) data processor for monitoring events related to different bus activity. The monitoring facility is accessible via a bus connection the IC. Events include device acquisition and ownership time, and the number of requests and grants on a given bus. The events are counted as occurrences and durations by a number of event counters integrated in the IC. The IC can notify software when the counters overflow. The IC may feature multiple clock domains, including, for instance, multiple bus interfaces operating at different clock frequencies, in which events from different clock domains may be tracked by the same counter. In one embodiment, the performance monitoring facility is integrated into an I/O processor (IOP) die that complies with the popular intelligent I/O (I2O) and Peripheral Components Interconnect (PCI) specifications.

Abstract: Real-time performance monitoring facility in an integrated circuit (IC) data processor for monitoring events related to different bus activity. The monitoring facility is accessible via a bus connection the IC. Events include device acquisition and ownership time, and the number of requests and grants on a given bus. The events are counted as occurrences and durations by a number of event counters integrated in the IC. The IC can notify software when the counters overflow. The IC may feature multiple clock domains, including, for instance, multiple bus interfaces operating at different clock frequencies, in which events from different clock domains may be tracked by the same counter. In one embodiment, the performance monitoring facility is integrated into an I/O processor (IOP) die that complies with the popular intelligent I/O (I2O) and Peripheral Components Interconnect (PCI) specifications.

Abstract: A 32-bit mode operation for a typical 64-bit ECC memory subsystem. In 32-bit mode, each data block will have an 8-bit ECC value, which is consistent with ECC values generated for 64-bit data. This is achieved by prefixing the data with 32 zeroes. When reading out data, memory faults can be corrected and detected using ECC techniques on a zero prefixed data block that is read out of the memory. This allows a memory subsystem to be optimized for bandwidth and latency depending upon this application.

Abstract: A message unit that provides a hardware queue interface between a host processor and a local processor handling I/O operations in an I/O platform. Circuitry manages the head and tail pointers of an inbound free queue, an inbound post queue, an outbound free queue and an outbound post queue. Circuitry is also provided for enabling a host processor or bus agent to access these queues in a single bus transaction by reading or writing inbound port registers or outbound port registers. The queue elements contain handles of message buffers. The invention automatically performs the specific task of locating the next element in a queue, altering that element, and modifying a queue descriptor (i.e., a head or a tail pointer) to indicate the next element for a next queue access. A plurality of registers are used for selectively interrupting either the host processor or the local processor when the queues are written to by either the host processor, a bus agent, or the local processor.

Abstract: An application accelerator unit (AAU) that is integrated as part of a data processor, such as an I/O processor (IOP) integrated circuit. In one embodiment, the AAU includes logic for improving the performance of storage applications such as Redundant Array of Inexpensive Disks (RAID). The AAU performs boolean operations such as exclusive-or (XOR) on multiple blocks of data to form the image parity block which is then written to the redundant disk array. Additionally, the AAU may feature adder logic configured to perform an addition such as a network header checksum calculation on each data packet. The AAU includes a memory-mapped programming interface that allows software executed by a core processor in the IOP to utilize the AAU for accelerating storage and networking applications as well as for local memory DMA-type transfers, using the chain descriptor construct.

Abstract: A message unit that provides a hardware queue interface between a host processor and a local processor handling I/O operations in an I/O platform. Circuitry manages the head and tail pointers of an inbound free queue, an inbound post queue, an outbound free queue and an outbound post queue. Circuitry is also provided for enabling a host processor or bus agent to access these queues in a single bus transaction by reading or writing inbound port registers or outbound port registers. The queue elements contain handles of message buffers. The invention automatically performs the specific task of locating the next element in a queue, altering that element, and modifying a queue descriptor (i.e., a head or a tail pointer) to indicate the next element for a next queue access. A plurality of registers are used for selectively interrupting either the host processor or the local processor when the queues are written to by either the host processor, a bus agent, or the local processor.

Abstract: A multi-functional device that integrates a high performance processor into a PCI to PCI bus bridge. The invention consolidates a high performance processor, a PCI to PCI bus bridge, PCI bus-processor address translation unit, direct memory acces's (DMA) controller, memory controller, secondary PCI bus arbitration unit, inter-integrated circuit (I.sup.2 C) bus interface unit, advanced programmable interrupt (APIC) bus interface unit, and a messaging unit into a single system which utilizes a local memory. The PCI bus is an industry standard high performance, low latency system bus. The PCI to PCI bridge provides a connection path between two independent 32-bit PCI buses and provides the ability to overcome PCI electrical loading limits. The addition of the local processor brings intelligence to the PCI bus bridge.

Abstract: A wait state mechanism for lengthening a microprocessor's bus cycle to allow data transfers between slower off-chip devices. A microprocessor is responsive to a bus control signal generated by external programmable logic which instructs the microprocessor to insert wait states of varying number depending on the component involved in a bus transaction. The microprocessor receives only a single input from the programmable logic and varies its bus cycle length accordingly.

Abstract: Dynamic appending of chain descriptors is described with reference to a computer system having a host processor, a DMA unit, a host memory and an external memory wherein the DMA unit controls transference of data between the host memory and the external memory based upon data transference parameters specified in chain descriptors created by the host processor and stored as data structures within the host memory. In accordance with one method and apparatus described herein, dynamic appending of chain descriptors is achieved by employing a resume bit stored within a register of the DMA unit. The host processor, upon creating a new group of chain descriptors to be appended to a previous group, updates a link value within a last chain descriptor of the previous group to point to the first chain descriptor of the new group and also sets the resume bit within the DMA unit.

Abstract: A micro processor emulator in which a set of core micro processor registers are the communication interface between an external system and a core-ported memory. The registers are connected to a serial scan port for transfer of information between a halted emulation environment and the external system. The serial port includes a command register that receives a jump address to initiate execution of a software monitor. Two special bits are provided in the command register, one that indicates a break, and one that indicates a Fast Break GO. This provides a break mechanism for a micro processor chip which does not have a dedicated memory bus. This break mechanism is the mechanism by which a halt or an asynchronous break is effected. After a fast break, the Fast Break GO mechanism does the action described by one command, and then immediately goes back to emulation without any external processor intervention.