摘要:
A queuing apparatus having a hierarchy of queues, in one of a number of aspects, is configured to control backpressure between processors in a multiprocessor system. A fetch queue is coupled to an instruction cache and configured to store first instructions for a first processor and second instructions for a second processor in an order fetched from the instruction cache. An in-order queue is coupled to the fetch queue and configured to store the second instructions accepted from the fetch queue in response to a write indication. An out-of-order queue is coupled to the fetch queue and to the in-order queue and configured to store the second instructions accepted from the fetch queue in response to an indication that space is available in the out-of-order queue, wherein the second instructions may be accessed out-of-order with respect to other second instructions executing on different execution pipelines.
摘要:
Apparatus and methods provide early access of instructions. A fetch queue is coupled to an instruction cache and configured to store a mix of processor instructions for a first processor and coprocessor instructions for a second processor. A coprocessor instruction selector is coupled to the fetch queue and configured to copy coprocessor instructions from the fetch queue. A queue is coupled to the coprocessor instruction selector and from which coprocessor instructions are accessed for execution before the coprocessor instruction is issued to the first processor. Execution of the copied coprocessor instruction is started in the coprocessor before the coprocessor instruction is issued to a processor. The execution of the copied coprocessor instruction is completed based on information received from the processor after the coprocessor instruction has been issued to the processor.
摘要:
A queuing apparatus having a hierarchy of queues, in one of a number of aspects, is configured to control backpressure between processors in a multiprocessor system. A fetch queue is coupled to an instruction cache and configured to store first instructions for a first processor and second instructions for a second processor in an order fetched from the instruction cache. An in-order queue is coupled to the fetch queue and configured to store the second instructions accepted from the fetch queue in response to a write indication. An out-of-order queue is coupled to the fetch queue and to the in-order queue and configured to store the second instructions accepted from the fetch queue in response to an indication that space is available in the out-of-order queue, wherein the second instructions may be accessed out-of-order with respect to other second instructions executing on different execution pipelines.
摘要:
Systems and methods for tracking data hazards in a processor. The processor comprises a pipelined architecture configured to execute a first instruction and a second instruction, wherein the second instruction is older than the first instruction. At least one of the first and second instructions comprises at least one operand expressed as a range of registers. Hazard detection logic is configured to compare the first instruction and the second instruction to determine if there is a data hazard, prior to expanding the second instruction.
摘要:
Methods and apparatus for processing instructions by elaboration of instructions prior to issuing the instructions for execution are described. An instruction is received at a hybrid instruction queue comprised of a first queue and a second queue. When the second queue has available space, the instruction is elaborated to expand one or more bit fields to reduce decoding complexity when the elaborated instruction is issued, wherein the elaborated instruction is stored in the second queue. When the second queue does not have available space, the instruction is stored in an unelaborated form in a first queue. The first queue is configured as an exemplary in-order queue and the second queue is configured as an exemplary out-of-order queue.
摘要:
Apparatus and methods provide early access of instructions. A fetch queue is coupled to an instruction cache and configured to store a mix of processor instructions for a first processor and coprocessor instructions for a second processor. A coprocessor instruction selector is coupled to the fetch queue and configured to copy coprocessor instructions from the fetch queue. A queue is coupled to the coprocessor instruction selector and from which coprocessor instructions are accessed for execution before the coprocessor instruction is issued to the first processor. Execution of the copied coprocessor instruction is started in the coprocessor before the coprocessor instruction is issued to a processor. The execution of the copied coprocessor instruction is completed based on information received from the processor after the coprocessor instruction has been issued to the processor.
摘要:
In a denormal support mode, the normalization circuit of a floating-point adder is used to normalize or denormalized the output of a floating-point multiplier. Each floating-point multiply instruction is speculatively converted to a multiply-add instruction, with the addend forced to zero. This preserves the value of the product, while normalizing or denormalizing the product using the floating-point adder's normalization circuit. When the operands to the multiply operation are available, they are inspected. If the operands will not generate an unnormal intermediate product or a denormal final product, the add operation is suppressed, such as by operand-forwarding. Additionally, each non-fused floating-point multiply-add instruction is replaced with a multiply-add instruction having a zero addend, and a floating-point add instruction having the addend of the original multiply-add instruction is inserted into the instruction stream. Upon inspection of the operands, if an unnormal intermediate result or a denormal final result will not occur, the addend may be restored to the multiply-add instruction and the add instruction converted to a NOP.
摘要:
A floating-point processor with selectable subprecision includes a register configured to store a plurality of bits in a floating-point format, a controller, and a floating-point mathematical operator. The controller is configured to select a subprecision for a floating-point operation, in response to user input. The controller is configured to determine a subset of the bits, in accordance with the selected subprecision. The floating-point operator is configured to perform the floating-point operation using only the subset of the bits. Excess bits that are not used in the floating-point operation may be forced into a low-leakage state. The output value resulting from the floating-point operation is either truncated or rounded to the selected subprecision.
摘要:
Data from a source domain operating at a first data rate is transferred to a FIFO in another domain operating at a different data rate. The FIFO buffers data before transfer to a sink for further processing or storage. A source side counter tracks space available in the FIFO. In disclosed examples, the initial counter value corresponds to FIFO depth. The counter decrements in response to a data ready signal from the source domain, without delay. The counter increments in response to signaling from the sink domain of a read of data off the FIFO. Hence, incrementing is subject to the signaling latency between domains. The source may send one more beat of data when the counter indicates the FIFO is full. The last beat of data is continuously sent from the source until it is indicated that a FIFO position became available; effectively providing one more FIFO position.
摘要:
Selective power control of one or more processing elements matches a degree of parallelism to requirements of a task performed in a highly parallel programmable data processor. For example, when program operations require less than the full width of the data path, a software instruction of the program sets a mode of operation requiring a subset of the parallel processing capacity. At least one parallel processing element, that is not needed, can be shut down to conserve power. At a later time, when the added capacity is needed, execution of another software instruction sets the mode of operation to that of the wider data path, typically the full width, and the mode change reactivates the previously shut-down processing element.