Abstract: There is disclosed a processing system comprising: 1) a first data processor comprising a unified memory architecture for receiving memory access requests from an external bus coupled to the first data processor; 2) a memory coupled to the first data processor and controlled by the unified memory architecture, the memory storing a first plurality of instructions executable by the first data processor; and 3) a second data processor coupled to the external bus and capable of sending the memory access requests to the first data processor, wherein the memory access requests access data used by the second data processor stored in the memory.

Abstract: There is disclosed an apparatus for providing a virtual PCI device for use in a processing system comprising a data processor having an external peripheral bus coupled thereto in which peripheral devices associated with the external peripheral bus are controlled by accessing configuration circuitry associated with each of the peripheral devices. The apparatus comprises: a) an address trap circuit for detecting a configuration cycle accessing a virtual configuration address space associated with the virtual PCI device and generating an enable signal in response and b) an interrupt generation circuit associated with the address trap circuit that receives the enable signal and, in response, generates an interrupt signal that causes the data processor to execute instructions stored in system memory associated with the virtual device.

Abstract: A processing system having a CPU core and a cache transfers data between a first block of memory and a second block of memory that is preferably partitioned out of the cache as a non-cacheable scratchpad area and performs address calculations with protection and privilege checks without polluting the cache. Responsive to executing a predetermined instruction, the CPU core signals the cache to prevent caching data during transfer from system to scratchpad memory thereby reducing the number of bus turnarounds while maintaining byte granularity addressability.

Abstract: A processing system includes a graphics subsystem that directly renders raster data to system memory and moves bitmaps between locations within system memory with the graphics subsystem providing the data and a processor providing the virtual-to-physical addresses with privilege and protection check mechanisms.