Abstract: A prefetch device and method are disclosed that determines from which addresses to speculatively fetch data based on information collected regarding previous cache-miss addresses. A historical record showing a propensity to experience cache-misses at a particular address-offset from a prior cache-miss address within a region of memory provides an indication that data needed by future instructions has an increased likelihood to be located at a similar offset from a current cache-miss address. The prefetch device disclosed herein maintains a record of the relationship between a cache-miss address and subsequent cache-miss addresses for the most recent sixty-four unique data manipulation instructions that resulted in a cache-miss. The record includes a weighted confidence value indicative of how many cache-misses previously occurred at each of a selection of offsets from a particular cache-miss address.

Abstract: A first address is received and is used to determine a first address range. The first address range includes a second address range and a third address range. If the first address is in the second address range, a fourth address range is determined. The fourth address range is different from the first address range. Information is retrieved from a memory in response to determining that a second address is in the first address range or the fourth address range. If the first address is in the third address range, a fifth address range is determined. The fifth address range is different from the first address range. Other information is retrieved from the memory in response to determining the second address is in the first address range or the fifth address range.

Abstract: A prefetch device and method are disclosed that determines from which addresses to speculatively fetch data based on information collected regarding previous cache-miss addresses. A historical record showing a propensity to experience cache-misses at a particular address-offset from a prior cache-miss address within a region of memory provides an indication that data needed by future instructions has an increased likelihood to be located at a similar offset from a current cache-miss address. The prefetch device disclosed herein maintains a record of the relationship between a cache-miss address and subsequent cache-miss addresses for the most recent sixty-four unique data manipulation instructions that resulted in a cache-miss. The record includes a weighted confidence value indicative of how many cache-misses previously occurred at each of a selection of offsets from a particular cache-miss address.

Abstract: A first address is received and is used to determine a first address range. The first address range includes a second address range and a third address range. If the first address is in the second address range, a fourth address range is determined. The fourth address range is different from the first address range. Information is retrieved from a memory in response to determining that a second address is in the first address range or the fourth address range. If the first address is in the third address range, a fifth address range is determined. The fifth address range is different from the first address range. Other information is retrieved from the memory in response to determining the second address is in the first address range or the fifth address range.

Abstract: A method of rapidly detecting data errors includes generating a reference syndrome from data bits in a data word, the reference syndrome having at least a first portion and a second portion, generating a partial error code from the data bits and the first portion of the reference syndrome, and initiating an error recovery procedure if the partial error code contains any true values.

Abstract: The invention recasts the virtual register file frame calls to alias hazard detection in the hazard detect logic of the physical register file. By way of example, mapping to the stacked registers may be aliased with three sets of 32 registers rows, from 32 to 127, for data hazard calculations to decrease size implementation with minor performance decrease. The invention sacrifices occasional hazard detections—resulting in occasional pipeline stalls as a loss of processor performance—in order to remove the row-by-row dependencies on physical register size. The invention thus reduces the logic requirements associated with the “height” and “width” of the register file: “height” corresponds to the number of registers (e.g., 128), and “width” corresponds to the pipeline stages.

Abstract: A method of rapidly detecting data errors includes generating a reference syndrome from data bits in a data word, the reference syndrome having at least a first portion and a second portion, generating a partial error code from the data bits and the first portion of the reference syndrome, and initiating an error recovery procedure if the partial error code contains any true values.

Abstract: A data processing system (10) having a bus controller (5) that uses a communication bus (22) which adapts to various system resources (7) and is capable of burst transfers. In one embodiment, the processor core (2) and system resources (7) supply control signals supplying required parameters of the next transfer. The bus controller is capable of transferring operands and/or instructions in incremental bursts from these system resources. Each transfer data burst has an associated unique access address where successive bytes of data are associated with sequential addresses and the burst increment equals the data port size. The burst capability is dependent on the ability of system resource (7) to burst data and can be inhibited with a transfer burst inhibit signal. The length of the desired data is controlled by a sizing signal from the core (2) or from cache and the increment size is supplied by the resource (7).

Abstract: A data processing system (10) having a bus controller (5) and a multiplexed communication bus (22) and provides a portion of the valid address information during the data phase. In one embodiment, in response to an address extension control signal, the bus controller (5) allocates the communication bus (22) to provide the address extension on conductors not needed for data, reducing the need for address latch circuitry. In an alternate embodiment, the bus controller (5) provides burst transfers where the processor core (2) increments a portion of each address with each data in the burst. For such burst transfers, the length of the desired data is controlled by a sizing signal (42) from the core (2) or from cache and the increment size is supplied by the system resource (7).