Abstract: One or more Shadow Register Files (SRF) are interposed between a Physical Register File (PRF) and a Backing Store (BS) in a shadow register file system. The SRFs comprise dual-port registers connected serially in a chain of arbitrary depth from the PRF. A Register Save Engine has random access to one port of the registers in the final SRF in the chain, and saves/restores data between the final SRF and the BS, e.g., RAM. As PRF registers are deallocated from calling procedures for use by called procedures, data are serially shifted from multi-port registers in the PRF through successive corresponding dual-port registers in SRFs, and are serially shifted back toward the multi-port registers as the PRF registers are reallocated to calling procedures. Since no procedure can access more than the number of registers in the PRF, the effective size of the PRF is increased, using less costly dual-port registers.

Abstract: A system and method of using an n-way cache are disclosed. In an embodiment, a method includes determining a first way of a first instruction stored in a cache and storing the first way in a list of ways. The method also includes determining a second way of a second instruction stored in the cache and storing the second way in the list of ways. In an embodiment, the first way may be used to access a first cache line containing the first instruction and the second way may be used to access a second cache line containing the second instruction.

Abstract: A processing system and method for transferring data in a processing system. The processing system includes a bus mastering device, a plurality of slave devices, and a bus interconnect configured to switch the bus mastering device between the slave devices. Each of the slave devices has a plurality of addresses. The bus interconnect includes a DMA controller configured to transfer data from a first one of the addresses to a second one of the addresses in response to a single bus command from the bus mastering device.

Abstract: In an embodiment, a method is disclosed that includes receiving a clock signal at a delay chain of a circuit device and determining a value of the clock signal at a selected point within the delay chain. The method also includes adjusting the selected point when the value does not indicate detection of an edge of the clock signal.

Abstract: Techniques for the design and use of a digital signal processor, including processing transmissions in a communications (e.g., CDMA) system. A modified Booth multiplication system and process determine a multiplicand, A, and a multiplier, B. Radix-m, (e.g., radix-4) Booth recoding on B generates “n” multiplication factors, where “n,” an integer, is approximating one half of the number of the multiplier bits. “n” partial products are generated using the “n” multiplication factors as multipliers of A. Then, a multiplication tree is formed using radix-m Booth encoding. The multiplication tree includes multiplier bits associated to generate a multiplication factors. In the event of a negative multiplication factor, a two's complement of A is formed by inverting the bits of A and associating a sticky “1” to complete the two's complementation. Furthermore, multiplication factors are reduced in multiple stages to a form sum and carry components of a pre-determined length.

Abstract: A processing system may include a memory configured to store data in a plurality of pages, a TLB, and a memory cache including a plurality of cache lines. Each page in the memory may include a plurality of lines of memory. The memory cache may permit, when a virtual address is presented to the cache, a matching cache line to be identified from the plurality of cache lines, the matching cache line having a matching address that matches the virtual address. The memory cache may be configured to permit one or more page attributes of a page located at the matching address to be retrieved from the memory cache and not from the TLB, by further storing in each one of the cache lines a page attribute of the line of data stored in the cache line.

Abstract: Apparatuses and methods for dual channel memory architecture with reduced interface pin requirements are presented. One memory architecture includes a memory controller, a first memory device coupled to the memory controller by a shared address bus and a first clock signal, and a second memory device coupled to the memory controller by the shared address bus and a second clock signal, where the polarity of the second clock signal is opposite of the first clock signal. A method for performing data transactions is presented. The method includes providing addressing signals over a shared address bus to a first memory device and a second memory device, providing clock signals to the memory devices which are reversed in polarity, where the clock signals are derived from a common clock signal, and transferring data to the memory devices over separate narrow data buses in an alternating manner based upon the clock signals.

Abstract: An instruction cache system having a virtually tagged instruction cache which, from a software program perspective, operates as if it were a physically tagged instruction cache is disclosed. The instruction cache system also includes a means for address translation which is responsive to an address translation invalidate instruction and a control logic circuit. The control logic circuit is configured to invalidate an entry in the virtually tagged instruction cache in response to the address translation invalidate instruction.

Abstract: Techniques for the design and use of a digital signal processor, including processing transmissions in a communications (e.g., code division multiple access) system. Power-efficient sign extension for Booth multiplication processes involves applying a sign bit in a Booth multiplication tree. The sign bit allows the Booth multiplication process to perform a sign extension step. This further involves one-extending a predetermined partial product row of the Booth multiplication tree using a sign bit for preserving the correct sign of the predetermined partial product row. The process and system resolve the signal value of the sign bit by generating a sign-extension bit in the Booth multiplication tree. The sign-extension bit is positioned in a carry-out column to extend the product of the Booth multiplication process.

Abstract: A method of expanding a conditional instruction having a plurality of operands within a pipeline processor is disclosed. The method identifies the conditional instruction prior to an issue stage and determines if the plurality of operands exceeds a predetermined threshold. The method expands the conditional instruction into a non-conditional instruction and a select instruction. The method further executes the non-conditional instruction and the select instruction in separate pipelines.

Abstract: Energy stored in bypass capacitors in a portable device may be conserved when a power supply voltage is collapsed reducing the need to recharge the bypass capacitors and thereby saving power. A bypass charge saving circuit includes a bypass capacitor, a power source having an output supply voltage that is switchable, a load circuit of the portable device coupled to the output supply voltage, and the bypass capacitor operable to filter the output supply voltage. Also, a transistor switch is operable to decouple a discharge path of the bypass capacitor through the load circuit when the transistor switch is disabled. Further, a controller is operable to turn off the output supply voltage and the transistor switch in order to conserve energy stored in the bypass capacitor.

Abstract: A main die and a stacked die are included in the same component package. A transmission gate (370) is implemented on the main die, and can be enabled to receive leakage current in a connection (318) between the main die and the stacked die, and to conduct the leakage current to a bonding pad (344) that is accessible external to the package. Thus, the connectivity between the main die and the stacked die can be tested after the dies are packaged. The transmission gate is disabled during high-speed testing and normal operation. The package can also include a multiplexer (364) that is enabled during high-speed testing to input and output test signals at the package level. A direction signal is used to indicate whether test signals are being input to or output from the main die.

Abstract: A cached memory system that can handle high-rate input data and ensure that an embedded DSP can meet real-time constraints is described. The cached memory system includes a cache memory located close to a processor core, an on-chip memory at the next higher memory level, and an external main memory at the topmost memory level. A cache controller handles paging of instructions and data between the cache memory and the on-chip memory for cache misses. A direct memory exchange (DME) controller handles user-controlled paging between the on-chip memory and the external memory. A user/programmer can arrange to have the instructions and data required by the processor core to be present in the on-chip memory well in advance of when they are actually needed by the processor core.

Abstract: A method and apparatus for caching instructions for a processor having multiple operating states. At least two of the operating states of the processor supporting different instruction sets. A block of instructions may be retrieved from memory while the processor is operating in one of the states. The instructions may be pre-decoded in accordance with said one of the states and loaded into cache. The processor, or another entity, may be used to determine whether the current state of the processor is the same as said one of the states used to pre-decode the instructions when one of the pre-decoded instructions in the cache is needed by the processor.

Abstract: The search key and key fields of a CAM in a cache are encoded with a Hamming distance of at least two to increase the speed of the CAM by ensuring each mismatching match line is discharged by at least two transistors in parallel. Where the cache is physically tagged, the search key is a physical address. The page address portion of the physical address is encoded prior to being stored in a TLB. The page offset bits are encoded in parallel with the TLB access, and concatenated with the encoded TLB entry. If a page address addresses a large memory page size, a plurality of corresponding sub-page addresses may be generated, each addressing a smaller page size. These sub-page addresses may be encoded and stored in a micro TLB. The encoded key and key field are tolerant of single-bit soft errors.

Abstract: The disclosure includes a latch structure and self-adjusting pulse generator using the latch. In an embodiment, the system includes a first latch and a pulse generator coupled to provide a timing signal to the first latch. The pulse generator includes a second latch that has characteristics matching the first latch.

Abstract: Techniques for the design and use of a digital signal processor, including (but not limited to) processing transmissions in a communications (e.g., CDMA) system. The disclosed method and system process interrupts arising in a multithreaded processor by receiving in an interrupt register a plurality of interrupts of a statistically indeterminate interrupt type and then associating a plurality of processing threads with the interrupt register for receiving the interrupt from the interrupt register. The method and system mask at least a subset of the plurality of processing threads so as to receive within each of the threads within the subset only ones of the plurality of interrupts of one or more predetermined types, thereby controlling on a per thread basis the processing of the plurality of interrupts according to the mask associated with a particular thread.

Abstract: Techniques for performing data tracing in an integrated circuit with multiple embedded memories are described. A trace module within the integrated circuit forms packets of trace data for memory accesses of the multiple memories. The trace module includes multiple data capture units (one for each memory) and a trace stream generator. Each data capture unit includes a register, a comparator, an address compressor, a data compressor, and a packetizer. The register stores an address for a prior memory access of the associated memory. The comparator compares an address for a current memory access against the address stored in the register. The address and data compressors perform address and data compression, respectively, for the current memory access. The packetizer forms a packet of trace data for the current memory access. The trace stream generator generates a stream containing trace data packets from all data capture units.

Abstract: A method of testing a memory is provided that includes initiating a test on a computer readable memory. The computer readable memory provides output data associated with the test. Further, the method includes selecting to receive the output data from a first register or a second register. In a particular embodiment, the method may include selecting to receive the output data from the first register or the second register by use of a control line. In another particular embodiment, the method may include selecting to receive the RAM input data from the first register or the second register by use of a control line. The control line is configured dynamically by hardware or software on cycle by cycle basis. In a particular embodiment, the test is a built-in-self-test (BIST).

Abstract: Techniques for the design and use of a digital signal processor, including (but not limited to) for processing transmissions in a communications (e.g., CDMA) system. A method and system control transferring data between debugging registers and digital signal processor processes in association with a power transition sequence of the digital signal processor. In a digital signal processor, debugging registers associate with the core processor process and the debugging process. Control bits control transferring data among the debugging registers, the core processor process and the debugging process. The control bit prevents transferring data among the debugging registers, the core processor process and the debugging process in the event of a power transition sequence. Control bits also prevent a power transition sequence of the digital signal processor in the event of transferring data among the debugging registers and the core processor process or the debugging process.