Abstract:
A microprocessor includes one or more registers which are architecturally defined to be used for at least two data formats. In one embodiment, the registers are the floating point registers defined in the x86 architecture, and the data formats are the floating point data format and the multimedia data format. The registers actually implemented by the microprocessor for the floating point registers use an internal format for floating point data. Part of the internal format is a classification field which classifies the floating point data in the extended precision defined by the x86 microprocessor architecture. Additionally, a classification field encoding is reserved for multimedia data. As the microprocessor begins execution of each multimedia instruction, the classification information of the source operands is examined to determine if the data is either in the multimedia class, or in a floating point class in which the significand portion of the register is the same as the corresponding significand in extended precision. If so, the multimedia instruction executes normally. If not, the multimedia instruction is faulted. Similarly, as the microprocessor begins execution of each floating point instruction, the classification information of the source operands is examined. If the data is classified as multimedia, the floating point instruction is faulted. A microcode routine is used to reformat the data stored in at least the source registers of the faulting instruction into a format useable by the faulting instruction. Subsequently, the faulting instruction is re-executed.
Abstract:
The present invention enables efficient matrix multiplication operations on parallel processing devices. One embodiment is a method for mapping CTAs to result matrix tiles for matrix multiplication operations. Another embodiment is a second method for mapping CTAs to result tiles. Yet other embodiments are methods for mapping the individual threads of a CTA to the elements of a tile for result tile computations, source tile copy operations, and source tile copy and transpose operations. The present invention advantageously enables result matrix elements to be computed on a tile-by-tile basis using multiple CTAs executing concurrently on different streaming multiprocessors, enables source tiles to be copied to local memory to reduce the number accesses from the global memory when computing a result tile, and enables coalesced read operations from the global memory as well as write operations to the local memory without bank conflicts.
Abstract:
In parallel processing devices, for streaming computations, processing of each data element of the stream may not be computationally intensive and thus processing may take relatively small amounts of time to compute as compared to memory accesses times required to read the stream and write the results. Therefore, memory throughput often limits the performance of the streaming computation. Generally stated, provided are methods for achieving improved, optimized, or ultimately, maximized memory throughput in such memory-throughput-limited streaming computations. Streaming computation performance is maximized by improving the aggregate memory throughput across the plurality of processing elements and threads. High aggregate memory throughput is achieved by balancing processing loads between threads and groups of threads and a hardware memory interface coupled to the parallel processing devices.
Abstract:
In parallel processing devices, for streaming computations, processing of each data element of the stream may not be computationally intensive and thus processing may take relatively small amounts of time to compute as compared to memory accesses times required to read the stream and write the results. Therefore, memory throughput often limits the performance of the streaming computation. Generally stated, provided are methods for achieving improved, optimized, or ultimately, maximized memory throughput in such memory-throughput-limited streaming computations. Streaming computation performance is maximized by improving the aggregate memory throughput across the plurality of processing elements and threads. High aggregate memory throughput is achieved by balancing processing loads between threads and groups of threads and a hardware memory interface coupled to the parallel processing devices.
Abstract:
An apparatus and method for superforwarding load operands in a microprocessor are provided. An execution unit in a microprocessor is configured to receive a load instruction and a subsequent instruction. If the load instruction corresponds to a simple load instruction, a destination operand of the load instruction can be superforwarded to a subsequent instruction if the subsequent instruction specifies a source operand that depends on the destination operand of the load instruction. The subsequent instruction is not required to wait until a load instruction executes or completes and can be scheduled and/or executed prior to or at the same time as the load instruction. Consequently, latencies associated with operand dependencies may be reduced.
Abstract:
A microprocessor configured to rapidly execute floating point store status word (FSTSW) type instructions that are immediately preceded by floating point compare (FCOM) type instructions is disclosed. FCOM-type instructions are modified to store their results to an architectural floating point status word and a temporary destination register. If an FSTSW-type instruction is detected immediately following an FCOM-type instruction, then the FSTSW-type instruction is transformed into a special fast floating point store status word (FSTSWEF) instruction. Unlike the FSTSW-type instruction, which is serializing and negatively impacts performance, the FSTSWEF instruction is not serializing and allows execution to continue without undue serialization. A computer system and method for rapidly executing FSTSW instructions immediately preceded by FCOM-type instructions are also disclosed.
Abstract:
A multi-function look-up table for determining output values for predetermined ranges of a first mathematical function and a second mathematical function. In one embodiment, the multi-function look-up table is a bipartite look-up table including a first plurality of storage locations and a second plurality of storage locations. The first plurality of storage locations store base values for the first and second mathematical functions. Each base value is an output value (for either the first or second function) corresponding to an input region which includes the look-up table input value. The second plurality of storage locations, on the other hand, store difference values for both the first and second mathematical functions. These difference values are used for linear interpolation in conjunction with a corresponding base value in order to generate a look-up table output value. The multi-function look-up table further includes an address control unit coupled to receive a first input value and a signal which indicates whether an output value is to be generated for the first or second mathematical function. The address control unit then generates a first address value from these signals which is in turn conveyed to the first and second plurality of storage locations. In response to receiving the first address value, the first and second plurality of storage locations are configured to output a first base value and a first difference value, respectively. The first base value and first difference value are then conveyed to an output unit configured to generate a look-up table output value from the two values.