Abstract: There is disclosed a data processor having a clustered architecture that comprises a plurality of clusters and an interrupt and exception controller. Each of the clusters comprises an instruction execution pipeline having N processing stages. Each of the N processing stages is capable of performing at least one of a plurality of execution steps associated with instructions being executed by the clusters. The interrupt and exception controller operates to (i) detect an exception condition associated with one of the executing instructions, wherein this executing instruction issued at time t1, and (ii) generate an exception in response to the exception condition upon completed execution of earlier ones of the executing instructions, these earlier executing instructions issued at time preceding t0.

Abstract: For use in a data processor comprising an instruction execution pipeline comprising N processing stages, a system and method of encoding constant operands is disclosed. The system comprises a constant generator unit that is capable of generating both short constant operands and long constant operands. The constant generator unit extracts the bits of a short constant operand from an instruction syllable and right justifies the bits in an output syllable. For long constant operands, the constant generator unit extracts K low order bits from an instruction syllable and T high order bits from an extension syllable. The right justified K low order bits and the T high order bits are combined to represent the long constant operand in one output syllable. In response to the status of op code bits located within a constant generation instruction, the constant generator unit enables and disables multiplexers to automatically generate the appropriate short or long constant operand.

Abstract: There is disclosed a data processor having a clustered architecture that comprises a plurality of clusters, an instruction cache and a power-down controller. Each of the clusters comprises an instruction execution pipeline having N processing stages. Each of the N processing stages is capable of performing at least one of a plurality of execution steps associated with instructions being executed by the clusters. The power-down controller monitors the instruction cache and each instruction execution pipeline to identify power-down conditions associated with the same and, in response to an identified power-down condition, at least one of: (i) bypasses performance of at least a portion of subsequent ones of the N processing stages associated with an executing instruction, (ii) powers down the instruction cache, and (iii) powers down the data processor.

Abstract: There is disclosed a data processor containing an instruction issue unit that efficiently transfers instruction bundles from a cache to an instruction pipeline. The data processor comprises 1) an instruction pipeline comprising N processing stages; and 2) an instruction issue unit for fetching into the instruction pipeline instructions fetched from the instruction cache, each of the fetched instructions comprising from one to S syllables.

Abstract: There is disclosed a data processor having a clustered architecture that comprises at least one branching cluster, at least one non-branching cluster and remote conditional branching control circuitry. Each of the clusters is capable of computing branch conditions, though only the branching cluster is operable to perform branch address computations. The remote conditional branching control circuitry, which is associated with each of the clusters, is operable in response to sensing a conditional branch instruction in a non-branching cluster to (i) cause the branching cluster to compute a branch address and a next program counter address,(ii) cause the non-branching cluster to compute a branch condition, and (iii) communicate the computed branch condition from the non-branching cluster to the branching cluster. The data processor then uses the computed branch condition to select one of the branch address or the next program counter address.

Abstract: There is disclosed bundle alignment and dispersal circuitry for use in a data processor.

Abstract: There is disclosed a data processor comprising: 1) an instruction execution pipeline comprising N processing stages for executing a load instruction; 2) a status register for storing a modifiable configuration value, the modifiable configuration value having a first value indicating the data processor is capable of executing a misaligned access handling routine and a second value indicating the data processor is not capable of executing a misaligned access handling routine; 3) a misalignment detection circuit for determining if the load instruction performs a misaligned access to a target address of the load instruction and, in response to a determination that the load instruction does perform a misaligned access, generating a misalignment flag; and 4) exception control circuitry capable of detecting the misalignment flag and in response thereto determining if the modifiable configuration value is equal to the first value.

Abstract: A cyclic redundancy check value is computed by iterating a loop in which the contents of an operand having a first CRC value and a data value are shifted 1 bit to the end at which the CRC value is located. A generator value is exclusive-RED into corresponding respective bits of the operand only if the bit shifted out of the operand by the shift was set. This is repeated until a data byte has been displaced entirely and a modified cyclic redundancy check value occupies the most significant bytes, but now incorporates the original data byte in modified form.