Abstract: A digital system and method of operation is provided in which the digital system has at least one processor, with an associated multi-segment memory circuit. Validity circuitry is connected to the memory circuit and is operable to indicate if each segment of the plurality of segments holds valid data. Block transfer circuitry is connected to the memory circuit and is operable to transfer a block of data to a selected portion of segments of the memory circuit such that a transfer to any segment within the selected portion of segments holding valid data is inhibited. A block transfer to a selected plurality of segments in the memory circuit is initiated (1600, 1624). During the block transfer, each segment is tested (1602) to detect if a segment within the selected plurality of segments holds valid data. A transfer within the block transfer to a segment is inhibited if the segment contains a valid data value (1604).

Abstract: A mobile device (10) manages tasks (18) using a scheduler (20) for scheduling tasks on multiple processors (12). To conserve energy, the set of tasks to be scheduled are divided into two (or more) subsets, which are scheduled according to different procedures. In a specific embodiment, the first subset contains tasks with the highest energy consumption deviation based on the processor that executes the task. This subset is scheduled according to a power-aware procedure for scheduling tasks primarily based on energy consumption criteria. If there is no failure, the second subset is scheduled according to a real-time constrained procedure that schedules tasks primarily based on the deadlines associated with the various tasks in the second subset. If there is a failure in either procedure, one or more tasks with the lowest energy consumption deviation are moved from the first subset to the second subset and the scheduling is repeated.

Abstract: A transport packet parser (42) includes a transport packet header decoder (50)for identifying a packet identifier (PID) and continuity counter (CC) associated with a current packet. The PID along with an enable (En) bit is input to an PID associative memory (52) in search mode to identify an address associated with the PID. The address is used to access a CC associated with a previous packet for the same PID in a random access memory (62). The previous continuity counter is used along with other header information to determine whether the current packets satisfies predetermined criteria. If so, the packet is passed to a transport packet buffer for further processing.

Abstract: A VIVT (virtual index, virtual tag) cache (18) uses an interruptible hardware clean function to clean dirty entries in the cache during a context switch. A MAX counter (82) and a MIN register (84) define a range of cache locations which are dirty. During the hardware clean function, the MAX counter (82) counts downward while cache entries at the address given by the MAX counter (82) are written to main memory (16) if the entry is marked as dirty. If an interrupt occurs, the MAX counter is disabled until a subsequent clean request is issued after the interrupt is serviced.

Abstract: A digital system and method of operation is provided in which several processors (590n) are connected to a shared cache memory resource (500). A translation lookaside buffer (TLB) (310n) is connected to receive a request virtual address from each respective processor. A set of address regions (pages) is defined within an address space of a back-up memory associated with the cache and write allocation in the cache is defined on a page basis. Each TLB has a set of entries that correspond to pages of address space and each entry provides a write allocate attribute (550) for the associated page of address space. During operation of the system, software programs are executed and memory transactions are performed. A write allocate attribute signal (550) is provided with each write transaction request. In this manner, the attribute signal is responsive to the value of the write allocation attribute bit assigned to an address region that includes the address of the write transaction request.

Abstract: A digital system and method of operation is which the digital system has a processor with a virtual machine environment for interpretively executing instructions. First, a sequence of instructions is received (404) for execution by the virtual machine. The sequence of instructions is examined (408-414) to determine if a certain type of iterative sequence is present. If the certain type of iterative sequence is present, the iterative sequence is replaced (412) with a proprietary code sequence. After the modifications are complete, the modified sequence is executed in a manner that a portion of the sequence of instructions is executed in an interpretive manner (418); and the proprietary code sequences are executed directly by acceleration circuitry (420).

Abstract: A digital system and method of operation is provided in which several processors (440, 450) are connected to a shared memory resource (460). Translation lookaside buffers (TLB) (400, 402) are connected to receive a request address (404a-n) from each respective processor. Each TLB has a set of entries that correspond to pages of address space. Each entry provides a set of task memory attributes (TMA) (412a-n) for the associated page of address space. Task memory attributes are defined by a task control block associated with a currently executing task. For each memory transfer request, the TLB accesses an entry corresponding to the request address and provides a translated physical memory address and a task memory attribute value associated with that requested address space page. Functional circuitry (470) performs pre/post-processing on data that is being transferred between a processor and the memory in accordance with the task memory attribute value provided by the TLB with each memory transfer request.

Abstract: A digital system and method of operation is provided in which a method is provided for cleaning a range of addresses in a storage region specified by a start parameter and an end parameter. An interruptible clean instruction (802) can be executed in a sequence of instructions (800) in accordance with a program counter. If an interrupt (804) is received during execution of the clean instruction, execution of the clean instruction is suspended before it is completed. After performing a context switch (810), the interrupt is serviced (820). Upon returning from the interrupt service routine (830, 834), execution of the clean instruction is resumed by comparing the start parameter and the end parameter provided by the clean instruction with a current content of a respective start register and end register used during execution of the clean instruction. If the same, execution of the clean instruction is resumed using the current content of the start register and end register.

Abstract: A method for generating program code for translating high level code into instructions for one of a plurality of target processors comprises first determining a desired program code characteristic corresponding to a target processor. Then, selecting one or more predefined program code modules from a plurality of available program code modules in accordance with said desired program code characteristic, and generating program code for translating high level code into instructions for said target processor from said selected one or more predefined program code modules. Preferably, the method comprises forming agglomerated program code from a plurality of program code modules in accordance with said desired program code characteristic.

Abstract: A memory traffic access controller (18) responsive to a plurality of requests to access a memory. The controller includes circuitry (18d) for associating, for each of the plurality of requests, an initial priority value corresponding to the request. The controller further includes circuitry (18b, 18d, 18e, 18f) for changing the initial priority value for selected ones of the plurality of requests to a different priority value. Lastly, the controller includes circuitry for outputting (18d) a signal to cause access of the memory in response to a request in the plurality of requests having a highest priority value.

Abstract: An on-screen display with variable resolution capability permits respective parts of a screen to be processed according to their respective resolution requirements. For any active window in the on-screen display, the data format used in memory to represent the pixels of that window can be determined, thereby permitting the window resolution to vary from window to window.

Abstract: A DSP (10) accesses internal memory using physical addresses and has a internal MMU (19) which allows the DSP (10) to work with a large virtual address space mapped to an external memory (20). The MMU (19) performs the translation between a virtual address and the physical address associated with the external memory (20). The MMU (19) includes a translation lookaside buffer (28) and walking table logic (32) for translating virtual addresses to physical addresses.

Abstract: Circuitry for identifying digital data packets, each comprising a useful signal and a header signal containing data pertaining to the contents of the useful signal is provided. The circuitry includes a means (30) for extracting data from each header signal, which data is representative of a corresponding useful signal, a means for storing reference data in a memory, at addresses each corresponding to a packet type, and a means for comparing the data extracted from each header signal with said reference data stored in memory, and for the delivery, to a data processing unit (32,34), of an address signal indicating the nature of the corresponding packet. The data storage means and the comparison means preferably employ an associative memory (38) adapted to ensure the simultaneous comparison of the data extracted from each header signal with the reference data stored in memory.

Abstract: A digital system and method of operation is provided in which several processors (1400, 1402, 1404) are connected to a shared resource (1432). Each processor has an access priority register (1410) that is loaded with an access priority value by software executing on the processor. Arbitration circuitry (1430) is connected to receive a request signal from each processor along with the access priority value from each access priority register. The arbitration circuitry is operable to schedule access to the shared resource according to the access priority values provided by the processors. A software priority state is established during execution of an instruction module on each of the several processors. An instruction is executed on each processor to form an access request to the shared resource. An access priority value is provided with each access request that is responsive to the software priority state of the respective processor.

Abstract: A memory traffic access controller (18) responsive to a plurality of requests to access a memory. The controller includes circuitry (18d) for associating, for each of the plurality of requests, an initial priority value corresponding to the request. The controller further includes circuitry (18b, 18d, 18e, 18f) for changing the initial priority value for selected ones of the plurality of requests to a different priority value. Lastly, the controller includes circuitry for outputting (18d) a signal to cause access of the memory in response to a request in the plurality of requests having a highest priority value.

Abstract: A DSP (10) accesses internal memory using physical addresses and has a internal MMU (19) which allows the DSP (10) to work with a large virtual address space mapped to an external memory (20). The MMU (19) performs the translation between a virtual address and the physical address associated with the external memory (20). The MMU (19) includes a translation lookaside buffer (28) and walking table logic (32) for translating virtual addresses to physical addresses.

Abstract: A digital system is provided with a several processors, a private level one (L1) cache associated with each processor, a shared level two (L2) cache having several segments per entry, and a level three (L3) physical memory. The shared L2 cache architecture is embodied with 4-way associativity, four segments per entry and four valid and dirty bits. When the L2-cache misses, the penalty to access to data within the L3 memory is high. The system supports miss under miss to let a second miss interrupt a segment prefetch being done in response to a first miss. Thus, an interruptible SDRAM to L2-cache prefetch system with miss under miss support is provided. A shared translation look-aside buffer (TLB) is provided for L2 accesses, while a private TLB is associated with each processor. A micro TLB (&mgr;TLB) is associated with each resource that can initiate a memory transfer.

Abstract: A digital system and method of operation is provided in which the digital system has at least one processor, with an associated multi-segment cache memory circuit (1806(n). Validity circuitry (VI) and dirty bit circuitry (DI) is connected to the memory circuit and is operable to indicate if each segment of the plurality of segments holds valid data. Block circuitry (700, 702) is connected to the set of valid bits and dirty bits and is operable to invalidate a selected range of lines in response to a directive from the first processor. The block circuitry has a start register (700) and an end register (702) each separately loadable by the processor. The block circuitry can invalidate either a single line or a block of lines in response to an operation command from the processor, depending on whether the end register is loaded or not. Likewise, the block circuitry can clean a single line or a block of lines in response to an operation command from the processor.

Abstract: A digital system is provided with a memory (506) shared by several initiator resources (540-550), wherein a portion of the initiator resources are big endian and another portion of the initiator resources are little endian. The memory is segregated into a set of regions by a memory management unit (MMU) (500-510) and an endianism attribute bit is defined for each region. For each memory request to the memory, the endianism attribute bit for the selected region is provided by the MMU. Each memory transaction request is completed in accordance with the endianism attribute of the selected region. Depending on the capability of a given initiator resource, the memory request address is adjusted to agree with the endianism attribute of the selected region, or an access fault is generated (530) if the endianism of the initiating resource does not match the endianism attribute of the selected memory region.

Abstract: A digital system and method of operation is provided in which several processing resources (340) and processors (350) are connected to a shared translation lookaside buffer (TLB) (300, 310(n)) of a memory management unit (MMU) and thereby access memory and devices. These resources can be instruction processors, coprocessors, DMA devices, etc. Each entry location in the TLB is filled during the normal course of action by a set of translated address entries (308, 309) along with qualifier fields (301, 302, 303) that are incorporated with each entry. Operations can be performed on the TLB that are qualified by the various qualifier fields. A command (360) is sent by an MMU manager to the control circuitry of the TLB (320) during the course of operation. Commands are sent as needed to flush (invalidate), lock or unlock selected entries within the TLB. Each entry in the TLB is accessed (362, 368) and the qualifier field specified by the operation command is evaluated (364).