Abstract: A cache memory system including a primary cache and an overflow cache that are searched together using a search address. The overflow cache operates as an eviction array for the primary cache. The primary cache is addressed using bits of the search address, and the overflow cache is addressed by a hash index generated by a hash function applied to bits of the search address. The hash function operates to distribute victims evicted from the primary cache to different sets of the overflow cache to improve overall cache utilization. A hash generator may be included to perform the hash function. A hash table may be included to store hash indexes of valid entries in the primary cache. The cache memory system may be used to implement a translation lookaside buffer for a microprocessor.

Abstract: A processor including a memory controller for interfacing an external memory and a programmable functional unit (PFU). The PFU is programmed by a PFU program to modify operation of the memory controller, in which the PFU includes programmable logic elements and programmable interconnectors. For example, the PFU is programmed by the PFU program to add a function or otherwise to modify an existing function of the memory controller enhance its functionality during operation of the processor. In this manner, the functionality and/or operation of the memory controller is not fixed once the processor is manufactured, but instead the memory controller may be modified after manufacture to improve efficiency and/or enhance performance of the processor, such as when executing a corresponding process.

Abstract: A processor with an expandable instruction set architecture for dynamically configuring execution resources. The processor includes a programmable execution unit (PEU) that may be programmed to perform a user-defined function in response to a user-defined instruction (UDI). The PEU includes programmable logic elements and programmable interconnectors that are collectively programmed to perform at least one processing operation. A UDI loader is responsive to a UDI load instruction that specifies a UDI and a location of programming information that is used to program the PEU. The PEU may be programmed for one or more UDIs for one or more processes. An instruction table stores each UDI and corresponding information to identify the UDI and possibly to reprogram the PEU if necessary. A UDI handler consults the instruction table to identify a received UDI and to send corresponding information to the PEU to execute the corresponding user-defined function.

Abstract: A processor includes a processing core that detects a predetermined program is running on the processor and looks up a prefetch trait associated with the predetermined program running on the processor, wherein the prefetch trait is either exclusive or shared. The processor also includes a hardware data prefetcher that performs hardware prefetches for the predetermined program using the prefetch trait. Alternatively, the processing core loads each of one or more range registers of the processor with a respective address range in response to detecting that the predetermined program is running on the processor. Each of the one or more address ranges has an associated prefetch trait, wherein the prefetch trait is either exclusive or shared. The hardware data prefetcher performs hardware prefetches for the predetermined program using the prefetch traits associated with the address ranges loaded into the range registers.

Abstract: A processor includes first and second processing cores configured to support first and second respective subsets of features of its instruction set architecture (ISA) feature set. The first subset is less than all the features of the ISA feature set. The first and second subsets are different but their union is all the features of the ISA feature set. The first core detects a thread, while being executed by the first core rather than by the second core, attempted to employ a feature not in the first subset and, in response, to indicate a switch from the first core to the second core to execute the thread. The unsupported feature may be an unsupported instruction or operating mode. A switch may also be made if the lower performance/power core is being over-utilized or the higher performance/power core is being under-utilized.

Abstract: A processor includes a prefetcher that prefetches data in response to memory accesses, wherein each memory access has an associated memory access type (MAT) of a plurality of predetermined MATs. The processor also includes a table that holds scores that indicate effectiveness of the prefetcher to prefetch data with respect to the plurality of predetermined MATs. The prefetcher prefetches data in response to memory accesses at a level of aggressiveness based on the scores held in the table and the associated MATs of the memory accesses.

Abstract: A processor including a programmable prefetcher for prefetching information from an external memory. The programmable prefetcher includes a load monitor, a programmable prefetch engine, and a prefetch requester. The load monitor tracks load requests issued by the processor to retrieve information from the external memory. The programmable prefetch engine is configured to be programmed by at least one prefetch program to operate as a programmed prefetcher, such that during operation of the processor, the programmed prefetcher generates at least one prefetch address based on the load requests issued by the processor. The requester uses each generated prefetch address to prefetch information from the external memory. A prefetch memory may store one or more prefetch programs and a prefetch programmer may be included to select from among stored prefetch programs to program the prefetcher based on an executing process. Each prefetch program may be configured according to a prefetch definition.

Abstract: A processor including a front end, at least one load pipeline, and a memory system that further includes a programmable prefetcher for prefetching information from an external memory. The front end converts fetched program instructions into microinstructions including load microinstructions and dispatches microinstructions for execution. The load pipeline executes dispatched load microinstructions and provides load requests to the memory system. The programmable prefetcher includes a load monitor, a programmable prefetch engine, and a prefetch requester. The load monitor tracks the load requests. The prefetch engine is configured to be programmed by at least one prefetch program to operate as a programmed prefetcher, such that during operation of the processor, the programmed prefetcher generates at least one prefetch address based on the load requests issued by the processor. The prefetch requester submits the at least one prefetch address to prefetch information from the memory system.

Abstract: A processor includes an indicator configured to indicate a first mode or a second mode and a functional unit configured to perform computations with a full degree of accuracy when the indicator indicates the first mode and to perform computations with less than the full degree of accuracy when the indicator indicates the second mode.

Abstract: A conversion system that converts a standard executable program according to a predetermined ISA into a custom executable program executable by a general purpose processor. The processor includes a PEU that is programmable to execute a UDI. The conversion system includes a PEU programming tool that converts a functional description of a processing operation to be performed by the PEU of the processor into programming information for the PEU to perform the processing operation in response to the UDI. A converter converts the standard executable program into the custom executable program and includes an optimization routine that replaces a portion of the standard executable program with the specified UDI and that inserts the UDI into the custom executable program, and that further inserts a UDI load instruction that specifies the UDI and a location of the programming information in the custom executable program.

Abstract: A compiler system that converts an application source program into an executable program according to a predetermined ISA executable by a general purpose processor. The processor includes a PEU that is programmable to execute a UDI. The compiler system includes a PEU programming tool that converts a functional description of a processing operation to be performed by the PEU of the processor into programming information for programming the PEU to perform the processing operation in response to the specified UDI. The compiler system includes a compiler that converts the application source program into the executable program, which includes an optimization routine that represents a portion of the application source program with the specified UDI and that inserts the UDI into the executable program, and that further inserts into the executable program a UDI load instruction that specifies the UDI and a location of the programming information in the executable program.

Abstract: A set associative cache memory comprises an M×N memory array of storage entries arranged as M sets by N ways, both M and N are integers greater than one. Within each group of P mutually exclusive groups of the M sets, the N ways are separately powerable. A controller, for each group of the P groups, monitors a utilization trend of the group and dynamically causes power to be provided to a different number of ways of the N ways of the group during different time instances based on the utilization trend.

Abstract: A microprocessor comprises a cache including a tag array; a tagpipe that arbitrates access to the tag array; and a logic analyzer for investigating a starvation, livelock, or deadlock condition. The logic analyzer, which comprises read logic coupled to the tagpipe, is configured to record snapshots of transactions to access the tag array.

Abstract: A microprocessor includes a plurality of dynamically reconfigurable functional units, a fingerprint, and a fingerprint unit. As the plurality of dynamically reconfigurable functional units execute instructions according to a first configuration setting, the fingerprint unit accumulates information about the instructions according to a mathematical operation to generate a result. The microprocessor also includes a reconfiguration unit that reconfigures the plurality of dynamically reconfigurable functional units to execute instructions according to a second configuration setting in response to an indication that the result matches the fingerprint.

Abstract: A controller for controlling a dynamic random access memory (DRAM) comprising a plurality of blocks. A block is one or more units of storage in the DRAM for which the DRAM controller can selectively enable or disable refreshing. The DRAM controller includes flags each for association with a block of the blocks of the DRAM. A sanitize controller determines a block is to be sanitized and in response sets a flag associated with the block and disables refreshing the block. In response to subsequently receiving a request to read data from a location in the block, if the flag is clear, the DRAM controller reads the location and returns data read from it. If the flag is set, the DRAM controller refrains from reading the DRAM and returns a value of zero.

Abstract: A superscalar pipelined microprocessor includes a register set defined by an instruction set architecture of the microprocessor, execution units, and a store unit, coupled to the cache memory and distinct from the other execution units of the microprocessor. The store unit comprises an ALU. The store unit receives an instruction that specifies a source register of the register set and an operation to be performed on a source operand to generate a result. The store unit reads the source operand from the source register. The ALU performs the operation on the source operand to generate the result, rather than forwarding the source operand to any of the other execution units of the microprocessor to perform the operation on the source operand to generate the result. The store unit operatively writes the result to the cache memory.

Abstract: A microprocessor comprises a cache including a tag array; a tag pipeline that arbitrates access to the tag array; and a pattern detector. The pattern detector comprises a register; a decoder that decodes transaction type identifiers of tagpipe arbs advancing through the tag pipeline; and an accumulator that accumulates into the register the transaction type identifiers of a plurality of tagpipe arbs that advance through the tag pipeline.

Abstract: A processor includes a cache memory having a plurality of entries. Each of the entries holds data of a cache line, a state of the cache line and a tag of the cache line. The cache memory includes an engine comprising one or more finite state machines. The processor also includes an interface to a bus over which the processor writes back modified cache lines from the cache memory to the system memory in response to encountering an architectural writeback and invalidate instruction. The processor also invalidates the state of the entries of the cache memory in response to encountering the architectural writeback and invalidate instruction. In response to being instructed to perform a cache diagnostic operation, for each entry of the entries, the engine writes the state and the tag of the entry on the bus and does not invalidate the state of the entry.

Abstract: A set associative cache memory, comprising: an array of storage elements arranged as N ways; an allocation unit that allocates the storage elements of the array in response to memory accesses that miss in the cache memory; wherein each of the memory accesses has an associated memory access type (MAT) of a plurality of predetermined MATs, wherein the MAT is received by the cache memory; a mapping that, for each MAT of the plurality of predetermined MATs, associates the MAT with a subset of one or more ways of the N ways; wherein for each memory access of the memory accesses, the allocation unit allocates into a way of the subset of one or more ways that the mapping associates with the MAT of the memory access; and wherein the mapping is dynamically updatable during operation of the cache memory.

Abstract: A set associative cache memory, comprising: an array of storage elements arranged as M sets by N ways, each set belongs in one of L mutually exclusive groups; an allocation unit allocates the storage elements in response to memory accesses that miss in the cache; each memory access has an associated memory access type (MAT) of a plurality of predetermined MAT; a mapping, for each group of the L mutually exclusive groups: for each MAT, associates the MAT with a subset of the N ways; and for each memory access, the allocation unit allocates into a way of the subset of ways that the mapping associates with the MAT of the memory access and with one of the L mutually exclusive groups in which the selected set belongs.