Abstract: An integrated circuit for processing communication packets having separate data buffers and separate state information buffers. Each data buffer and each state information buffer (hereinafter termed resources) has an associated in-use counter. Multiple events can share the same resource. The counter associated with a resource is incremented when a resource becomes associated with a particular event. The counter associated with a resource is decremented when an event completes the use of that particular resource. When the in-use counter for a resource becomes zero, the in-use counter indicates that the resource is unassigned and that the resource can be assigned to a new event.

Abstract: An integrated circuit processes communication packets and comprises a pointer cache and control logic. The pointer cache store pointers that correspond to external buffers that are external to the integrated circuit and configured to store the communication packets. The control logic allocates the external buffers as the corresponding pointers are read from the pointer cache and de-allocates the external buffers as the corresponding pointers are written back to the pointer cache.

Abstract: An integrated circuit processes a communication packet and comprises a core processor and scheduling circuitry. The core processor executes a software application that directs the core processor to process the communication packet. The scheduling circuitry retrieves first scheduling parameters cached in a context buffer for the packet and executes a first algorithm based on the first scheduling parameters to schedule subsequent transmission of the communication packet.

Abstract: Circuitry to free the core processor from performing the explicit read operation required to read data into the internal register set. The processor's register set is expanded and a “shadow register” set is provided. While the core processor is processing one event the “context” and “data” and other associated information for the next event is loaded into the shadow register set. When the core processor finishes processing an event, the core processor switches to the shadow register set and it can begin processing the next event immediately. With short service routines, there might not be time to fully pre-fetch the “context” and “data” associated with the next event before the current event ends. In this case, the core processor still starts processing the next event and the pre-fetch continues during the event processing.

Abstract: An integrated circuit for processing communication packets having separate data buffers and separate state information buffers. Each data buffer and each state information buffer (hereinafter termed resources) has an associated in-use counter. Multiple events can share the same resource. The counter associated with a resource is incremented when a resource becomes associated with a particular event. The counter associated with a resource is decremented when an event completes the use of that particular resource. When the in-use counter for a resource becomes zero, the in-use counter indicates that the resource is unassigned and that the resource can be assigned to a new event.

Abstract: An integrated circuit comprises co-processor circuitry and a core processor. The co-processor circuitry comprises context buffers and data buffers. The co-processor circuitry receives and stores one of the communication packets in one of the data buffers. The co-processor circuitry correlates the one communication packet with one of a plurality of channel descriptors. The co-processor circuitry associates the one data buffer with one of the context buffers holding the one channel descriptor to maintain the correlation between the one communication packet and the one channel descriptor. The co-processor circuitry prevents multiple valid copies of the one channel descriptor from existing in the context buffers. In some examples of the invention, this is accomplished by tracking a number of the data buffers associated with the one context buffer.

Abstract: An integrated circuit processes communication packets and comprises a core processor and scheduling circuitry. The core processor executes a software application that directs the core processor to process the communication packets. The scheduling circuitry comprises multiple scheduling boards where at least some of the scheduling boards have multiple priority levels. The scheduling circuitry processes the scheduling boards to schedule and subsequently initiate transmission of the communication packets.

Abstract: An integrated circuit processes communication packets and comprises co-processor circuitry and a core processor. The co-processor circuitry is configured to operate in parallel with the core processor. The co-processor circuitry receives and stores the communication packets in data buffers. The co-processor circuitry also determines a prioritized processing order. The core processor executes a packet processing software application that directs the processor to process the communication packets in the data buffers based on the prioritized processing order.

Abstract: Circuitry to free the core processor from performing the explicit read operation required to read data into the internal register set. The processor's register set is expanded and a “shadow register” set is provided. While the core processor is processing one event the “context” and “data” and other associated information for the next event is loaded into the shadow register set. When the core processor finishes processing an event, the core processor switches to the shadow register set and it can begin processing the next event immediately. With short service routines, there might not be time to fully pre-fetch the “context” and “data” associated with the next event before the current event ends. In this case, the core processor still starts processing the next event and the pre-fetch continues during the event processing.

Abstract: An integrated circuit for processing communication packets having separate data buffers and separate state information buffers. Each data buffer and each state information buffer (hereinafter termed resources) has an associated in-use counter. Multiple events can share the same resource. The counter associated with a resource is incremented when a resource becomes associated with a particular event. The counter associated with a resource is decremented when an event completes the use of that particular resource. When the in-use counter for a resource becomes zero, the in-use counter indicates that the resource is unassigned and that the resource can be assigned to a new event.

Abstract: Methods and apparatus for processing cells in an asynchronous transfer mode (ATM) communication system. A group of bits comprises a primary scoreboard indicative of the scheduling status for cell time slots in a periodic container of cells, with each bit indicating the availability of a corresponding cell time slot. A connection identifier (ID) table is maintained with each location in the table corresponding to one of the cell time slots and thus a single primary scoreboard bit. A cell scheduling instruction specifies a connection ID for a virtual connection on an ATM transmission link. A processor searches the primary scoreboard until a bit corresponding to an available cell time slot is located, reserves the located cell slot by setting the corresponding bit, and stores the connection ID in the corresponding location in the connection ID table. A cell servicing instruction specifies an address in the connection ID table.

Abstract: Methods and apparatus for processing cells in an asynchronous transfer mode (ATM) communication system. A group of bits comprises a primary scoreboard indicative of the scheduling status for cell time slots in a periodic container of cells, with each bit indicating the availability of a corresponding cell time slot. A connection identifier (ID) table is maintained with each location in the table corresponding to one of the cell time slots and thus a single primary scoreboard bit. A cell scheduling instruction specifies a connection ID for a virtual connection on an ATM transmission link. A processor searches the primary scoreboard until a bit corresponding to an available cell time slot is located, reserves the located cell slot by setting the corresponding bit, and stores the connection ID in the corresponding location in the connection ID table. A cell servicing instruction specifies an address in the connection ID table.

Abstract: Methods and apparatus for processing cells in an asynchronous transfer mode (ATM) communication system. An ATM cell processor provides a cell buffer RAM (CBR) memory space gathering protocol which allows unused portions of a number of cell buffers to be addressed as a contiguous virtual memory space. The space gathering protocol may utilize a CPU or direct memory access (DMA) controller in an ATM cell processor to set a gather bit appended to a virtual CBR address. An address generator in the CBR detects the gather bit and translates those virtual addresses which include a set gather bit to physical addresses into the CBR memory space. The translation is performed by setting certain bits of the physical address to predetermined states to reach the unused 8 bytes at the bottom of any given 64-byte cell buffer, and shifting certain bits of the virtual address to other positions in the physical address to move from cell buffer to cell buffer in the contiguous virtual space.

Abstract: Methods and apparatus for processing cells in an asynchronous transfer mode (ATM) communication system. An ATM cell processor provides a modulo arithmetic feature which permits branching on the modulo portion of the result of an arithmetic operation. An arithmetic logic unit (ALU) or other processor instruction is modified to include a modulo field which specifies the number of right to left bits after which the result of the corresponding ALU operation will be truncated. Conditional branch instructions such as branch on zero result, branch on non-zero result, branch on negative result, branch on carry and branch on overflow may be configured to operate only on the modulo portion of the ALU instruction result and/or on a carry out of the most significant bit (MSB) position of the modulo portion.

Abstract: Methods and apparatus for processing cells in an asynchronous transfer mode (ATM) communication system. An ATM cell processor implements a "bubble" count technique which efficiently accommodates multiple layers of scheduling requests and/or external cell sources. In the case of multiple layers of scheduling requests, first and second primary scoreboards are provided for scheduling/servicing of, for example, higher and lower priority traffic, higher and lower cell rate traffic, or externally and internally generated traffic, respectively. A bubble count is maintained for the second scoreboard, and the count is incremented each time the first scoreboard is serviced and decremented each time an idle slot is encountered on the second scoreboard but not queued for transmission. Scheduling requests for the second scoreboard are then made at a target time plus the bubble count.

Abstract: Methods and apparatus for processing cells in an asynchronous transfer mode (ATM) communication system. An ATM cell processor includes a load multiple instruction which provides a burst transfer of a data block from an external control memory, and allows the result of a subsequent operation on a loaded value to be automatically written back to the control memory location from which it was previously read. The instruction may specify the address in the control memory of a data block to be retrieved, a destination register in a CPU register file into which the first retrieved halfword of a data block will be loaded, and a total number of halfwords to be retrieved. The instruction includes a link field option which directs the storage of information linking the processor registers which receive the retrieved halfwords to the control memory locations from which the halfwords were read.

Abstract: An integrated circuit processes communication packets and comprises a pointer cache and control logic. The pointer cache store pointers that correspond to external buffers that are external to the integrated circuit and configured to store the communication packets. The control logic allocates the external buffers as the corresponding pointers are read from the pointer cache and de-allocates the external buffers as the corresponding pointers are written back to the pointer cache.