Abstract: A processing device (10) provides general-purpose input/output pins (52) for use by software routines as needed. A data input register (54) has bits corresponding to each pin (52) for storing the value of the signal on the pin. A data output register (56) has bits corresponding to each pin for driving the signal on the pin (52) to a desired value. An output enable register (58) controls output buffers (62) coupled between the output register (56) and the pins (52). A plurality of mask registers (60) may be individually set to define a set a pins associated with the mask. Each of the data registers, the data input register (56), the data output register (58) and the output enable register (60) are accessed through a plurality of addresses, where the address specifies both the data register being accessed and an associated mask register (60). Logic (50) accesses the data registers in view of the state of the associated mask register (60).

Abstract: An interface for use with a multiprocessor computer system, having a host processor system and a graphics processor system. The interface permits extended functions to be developed on the host system or on another system, and subsequently loaded to the graphics processor system. The interface comprises software residing on both the host system side and the graphics system side, which operates at run time to permit the function to be called from a main program running on the host. The function's arguments are passed to the graphics system so that the function is executed by the graphics processor.