摘要:
A system, method and computer program product for translations in a computer system. The system includes a general purpose register containing a base address of an address translation table. The system also includes a millicode accessible special displacement register configured to receive a plurality of elements to be translated. The system further includes a multiplexer for selecting a particular one of the plurality of elements from the millicode accessible special displacement register and for generating a displacement or offset value. The system further includes an address generator for creating a combined address containing the base address from the general purpose register and the generated displacement or offset value.
摘要:
A system, method and computer program product for translations in a computer system. The system includes a general purpose register containing a base address of an address translation table. The system also includes a millicode accessible special displacement register configured to receive a plurality of elements to be translated. The system further includes a multiplexer for selecting a particular one of the plurality of elements from the millicode accessible special displacement register and for generating a displacement or offset value. The system further includes an address generator for creating a combined address containing the base address from the general purpose register and the generated displacement or offset value.
摘要:
A microprocessor equipped to provide hardware initiated prefetching, includes at least one architecture for performing: issuance of a prefetch instruction; writing of a prefetch address into a prefetch fetch address register (PFAR); attempting a prefetch according to the address; detecting one of a cache miss and a cache hit; and if there is a cache miss, then sending a miss request to a next cache level and attempting cache access in a non-busy cycle; and if there is a cache hit, then incrementing the address in the PFAR and completing the prefetch. A method and a computer program product are provided.
摘要:
Result and operand forwarding is provided between differently sized operands in a superscalar processor by grouping a first set of instructions for operand forwarding, and grouping a second set of instructions for result forwarding, the first set of instructions comprising a first source instruction having a first operand and a first dependent instruction having a second operand, the first dependent instruction depending from the first source instruction; the second set of instructions comprising a second source instruction having a third operand and a second dependent instruction having a fourth operand, the second dependent instruction depending from the second source instruction, performing operand forwarding by forwarding the first operand, either whole or in part, as it is being read to the first dependent instruction prior to execution; performing result forwarding by forwarding a result of the second source instruction, either whole or in part, to the second dependent instruction, after execution; wherein the operand forwarding is performed by executing the first source instruction together with the first dependent instruction; and wherein the result forwarding is performed by executing the second source instruction together with the second dependent instruction.
摘要:
A microprocessor equipped to provide hardware initiated prefetching, includes at least one architecture for performing: issuance of a prefetch instruction; writing of a prefetch address into a prefetch fetch address register (PFAR); attempting a prefetch according to the address; detecting one of a cache miss and a cache hit; and if there is a cache miss, then sending a miss request to a next cache level and attempting cache access in a non-busy cycle; and if there is a cache hit, then incrementing the address in the PFAR and completing the prefetch. A method and a computer program product are provided.
摘要:
A method for selectively accelerating early instruction processing including receiving an instruction data that is normally processed in an execution stage of a processor pipeline, wherein a configuration of the instruction data allows a processing of the instruction data to be accelerated from the execution stage to an address generation stage that occurs earlier in the processor pipeline than the execution stage, determining whether the instruction data can be dispatched to the address generation stage to be processed without being delayed due to an unavailability of a processing resource needed for the processing of the instruction data in the address generation stage, dispatching the instruction data to be processed in the address generation stage if it can be dispatched without being delayed due to the unavailability of the processing resource, and dispatching the instruction data to be processed in the execution stage if it can not be dispatched without being delayed due to the unavailability of the processing resource, wherein the processing of the instruction data is selectively accelerated using an address generation interlock scheme. A corresponding system and computer program product.
摘要:
A system and method for overlapping execution (OE) of instructions through non-uniform execution pipelines in an in-order processor are provided. The system includes a first execution unit to perform instruction execution in a first execution pipeline. The system also includes a second execution unit to perform instruction execution in a second execution pipeline, where the second execution pipeline includes a greater number of stages than the first execution pipeline. The system further includes an instruction dispatch unit (IDU), the IDU including OE registers and logic for dispatching an OE-capable instruction to the first execution unit such that the instruction completes execution prior to completing execution of a previously dispatched instruction to the second execution unit. The system additionally includes a latch to hold a result of the execution of the OE-capable instruction until after the second execution unit completes the execution of the previously dispatched instruction.
摘要:
Result and operand forwarding is provided between differently sized operands in a superscalar processor by grouping a first set of instructions for operand forwarding, and grouping a second set of instructions for result forwarding, the first set of instructions comprising a first source instruction having a first operand and a first dependent instruction having a second operand, the first dependent instruction depending from the first source instruction; the second set of instructions comprising a second source instruction having a third operand and a second dependent instruction having a fourth operand, the second dependent instruction depending from the second source instruction, performing operand forwarding by forwarding the first operand, either whole or in part, as it is being read to the first dependent instruction prior to execution; performing result forwarding by forwarding a result of the second source instruction, either whole or in part, to the second dependent instruction, after execution; wherein the operand forwarding is performed by executing the first source instruction together with the first dependent instruction; and wherein the result forwarding is performed by executing the second source instruction together with the second dependent instruction.
摘要:
A system and method for overlapping execution (OE) of instructions through non-uniform execution pipelines in an in-order processor are provided. The system includes a first execution unit to perform instruction execution in a first execution pipeline. The system also includes a second execution unit to perform instruction execution in a second execution pipeline, where the second execution pipeline includes a greater number of stages than the first execution pipeline. The system further includes an instruction dispatch unit (IDU), the IDU including OE registers and logic for dispatching an OE-capable instruction to the first execution unit such that the instruction completes execution prior to completing execution of a previously dispatched instruction to the second execution unit. The system additionally includes a latch to hold a result of the execution of the OE-capable instruction until after the second execution unit completes the execution of the previously dispatched instruction.
摘要:
A method, system, and computer program product for reduced overhead address mode change management in a pipelined, recycling microprocessor are provided. The recycling microprocessor includes logic executing thereon. The microprocessor also includes an instruction fetch unit (IFU) supporting computation of address adds in selected address modes and reporting non-equal comparison of the computation to the logic. The microprocessor further includes a fixed point unit determining whether the mode has changed and reporting changes to the logic. Upon determining the comparison yields an equal result but the mode has changed, a recycle event is triggered to ensure subsequent ofetches are relaunched in the correct mode and that no execution writebacks occur from work performed in an incorrect mode. For comparisons yielding a non-equal result and a changed mode, the logic clears bits set in response to the determinations, and a serialization event is taken to reset a corresponding pipeline for operation in the correct mode.