Abstract: An integrated circuit may include several components, one or more interfaces, an interconnect (e.g., a bus), and a controller. The components may each be configured to assert a read request to read data stored externally to the integrated circuit. The interfaces may be configured to output the read request asserted by one of the components and to receive data in response to outputting the request. The interconnect may be coupled to perform one or more data transactions to transmit the data from one of the interfaces to one or more of the components. In response to the read request asserted by one of the components, the controller may inhibit performance of a read transaction initiated by the read request dependent upon a comparison of a total number of outstanding data transactions to a maximum allowable number of outstanding data transactions.

Abstract: An external cache management unit for use with a 3D-RAM frame buffer and suitable for use in a computer graphics system is described. The unit may reduce power consumption within the 3D-RAM by performing partial block write-back according to status information stored in an array of dirty tag bits. Periodic level one cache block cleansing is provided for during empty memory cycles.

Abstract: A merge unit for the merging of tiles or arrays of pixels or samples, and suitable for use in a high performance graphics system is described. The unit may improve the utilization of memory bandwidth by combining non-intersecting tiles of pixels, and hence potentially reducing the number of storage operations to the memory.

Abstract: A memory array management unit suitable for use in a computer graphics system is described. The unit is especially designed to facilitate the storage of tiles of graphics data. Alignment detection between the tiles and memory block boundaries is provided for, with misalignments resulting in the automatic decimation to produce sub-tiles and generation of multiple memory write sequences.

Abstract: A graphics system for providing two-sided lighting. The graphics system may include a media processor and a hardware accelerator. The media processor may be configured to receive a stream of vertices, and to perform a two-sided lighting computation on each vertex resulting in front color and back color for each vertex. The hardware accelerator may be configured to (a) receive the vertices of the first stream along with the front and back color for each vertex, (b) assemble the vertices into polygons, (c) compute an orientation for each of the polygons, (d) select the front color or the back color of the vertices forming each polygon based on a result of the orientation computation for each polygon, and (e) render each polygon using the selected color of the vertices forming the polygon.

Abstract: A method and a system for stalling large pipelined designs. A computational pipeline may comprise a first module and a second module coupled together. The first module may propagate one or more signals to the second module. A stall-signal may be asserted in order to stall the computational pipeline if the second module is not ready to receive the one or more signals from the first module. The one or more signals propagated from the first module and the asserted stall-signal may be buffered in a stall-buffer. The asserted stall-signal may be propagated to the first module in a next cycle. The first module may be stalled in response to the first module receiving the propagated asserted stall-signal. Next, the asserted stall-signal may be propagated up the computational pipeline.

Abstract: An integrated circuit may include several components, one or more interfaces, an interconnect (e.g., a bus), and a controller. The components may each be configured to assert a read request to read data stored externally to the integrated circuit. The interfaces may be configured to output the read request asserted by one of the components and to receive data in response to outputting the request. The interconnect may be coupled to perform one or more data transactions to transmit the data from one of the interfaces to one or more of the components. In response to the read request asserted by one of the components, the controller may inhibit performance of a read transaction initiated by the read request dependent upon a comparison of a total number of outstanding data transactions to a maximum allowable number of outstanding data transactions.

Abstract: A graphics system may include a frame buffer that includes several sets of one or more memory banks and a cache. The frame buffer may load data from one of the memory banks into the cache in response to receiving a cache fill request. Each set of memory banks is accessible independently of each other set of memory banks. A frame buffer interface coupled to the frame buffer includes a plurality of cache fill request queues. Each cache fill request queue is configured to store one or more cache fill requests targeting a corresponding one of the sets of memory banks. The frame buffer interface is configured to select a cache fill request from one of the cache fill request queues that stores cache fill requests targeting a set of memory banks that is not currently being accessed and to provide the selected cache fill request to the frame buffer.

Abstract: An integrated circuit including logic for testing internal operation of the integrated circuit. The integrated circuit may comprise a plurality of internal functional blocks coupled by a plurality of internal buses. The integrated circuit may also comprise a set of test control input pins and a set of test output pins comprised on the integrated circuit. The integrated circuit may comprise selection logic. The selection logic comprises inputs coupled to various ones of the internal buses, an output coupled to the set of test output pins, and a select input coupled to receive select signals from the set of test control input pins. The selection logic is operable to select internal bus signals from an internal bus based on the select signals from the test control input pins, and the selection logic is configured to output the selected internal bus signals to the set of test output pins.

Abstract: A system for managing the control of a bi-directional data bus between a master unit and a slave unit. The master couples to the slave through a request opcode bus, a reply opcode bus and the data bus. If the master is in a bus driving state (with respect to the data bus) and receives a read request, the master relinquishes bus control and sends a read request through the request opcode bus. The slave unit assumes bus control and sends the requested data through the data bus. If the master is in a bus sensing state and receives a write request, the master sends a last read opcode to the slave via the request opcode bus, and waits for the slave to return a special token through the reply opcode bus. Upon receiving the special token the master unit assumes bus control and performs the write transaction.

Abstract: An external cache management unit for use with 3D-RAM and suitable for use in a computer graphics system is described. The unit maintains and tracks the status of level one cache memory in the 3D-RAM. The unit identifies dirty blocks of cache memory and prioritizes block cleansing based on a least used algorithm. Periodic block cleansing during empty memory cycles is provided for, and may also be prompted on demand.

Abstract: A method and system for synchronizing data streams and transferring control of resources between two processes in a graphics processor is described. The method allows for completion of pending operations of a first process in a manner that ensures the first process may be restarted without loss of data or process sequence. The processing pipeline is allowed to complete normal execution of all process operations required to reach a first process step that may be interrupted. The second process is initiated when the interruption of the first process is verified. Upon completion of the second process, the first process is reactivated at the next process step in sequence.

Abstract: A system and method for reading register contents from a computational pipeline having a plurality of computational units. The system includes a readback bus and a read control unit. The readback bus has a plurality of logic units coupled in a series. Each logic unit couples to a corresponding one of the computational units. The read control unit couples to each of the computational units through a corresponding load line, and is configured to assert a load signal on one of the load lines in response to a register read request. Each of the computational units is configured to transmit a data value from a selected register onto the readback bus in response to detecting an assertion of the load signal on its corresponding load line.

Abstract: A data queue optimized for receiving loosely packed graphics data and suitable for use in a computer graphics system is described. The data queue operates on first-in-first-out principals, and has a variable width input and output. The variable width on the input side facilitates the reception and storage of loosely packed data. The variable width output allows for the single-cycle output of multi-word data. Packing of the data occurs on the write-side of the FIFO structure.

Abstract: A memory interface controls read and write accesses to a memory device. The memory device includes a level-one cache, level-two cache and storage cell array. The memory interface includes a data request processor (DRP), a memory control processor (MCP) and a block cleansing unit (BCU). The MCP controls transfers between the storage cell array, the level-two cache and the level-one cache. In response to a read request with associated read clear indication, the DRP controls a read from a level-one cache block, updates bits in a corresponding dirty tag, and sets a mode indicator of the dirty tag to a the read clear mode. The modified dirty tag bits and mode indicator are signals to the BCU that the level-one cache block requires a source clear operation. The BCU commands the transfer of data from a color fill block in the level-one cache to the level-two cache.

Abstract: A graphics system includes a frame buffer, a write address generator, and a pixel buffer. A burst of pixels received from the frame buffer may not be in display order. In one embodiment, a write address generator calculates a write address for each pixel in the burst of pixels output from the frame buffer. The write address corresponds to a relative display order within the burst for each respective pixel. Each pixel in the burst is stored to its write address in the pixel buffer. This way, the pixels in the burst are stored in display order within the pixel buffer.

Abstract: A system and method for rasterizing and rendering graphics data is disclosed. Vertices may be grouped to form primitives such as triangles, which are rasterized using two-dimensional arrays of samples bins. To overcome fragmentation problems, the system's sample evaluation hardware may be configured to over-evaluate samples each clock cycle. Since a number of the samples will typically not survive evaluation because they will be outside the primitive being rendered, the remaining surviving samples may be combined into sets, with one set being forwarded to subsequent pipeline stages each clock cycle in order to attempt to keep the pipeline utilization high.

Abstract: A memory array management unit suitable for use in a computer graphics system is described. The unit is especially designed to facilitate the storage of tiles of graphics data. Alignment detection between the tiles and memory block boundaries is provided for, with misalignments resulting in the automatic decimation to produce sub-tiles and generation of multiple memory write sequences.

Abstract: An external cache management unit for use with a 3D-RAM frame buffer and suitable for use in a computer graphics system is described. The unit may reduce power consumption within the 3D-RAM by performing partial block write-back according to status information stored in an array of dirty tag bits. Periodic level one cache block cleansing is provided for during empty memory cycles.

Abstract: An external cache management unit for use with a 3D-RAM frame buffer and suitable for use in a computer graphics system is described. The unit may reduce power consumption within the 3D-RAM by performing partial block write-back according to status information stored in an array of dirty tag bits. Periodic level one cache block cleansing is provided for during empty memory cycles.