METHOD AND SYSTEM FOR SCALABLE, DATAFLOW-BASED, PROGRAMMABLE PROCESSING OF GRAPHICS DATA

A scalable pipelined pixel shader that processes packets of data and preserves the format of each packet at each processing stage. Each packet is an ordered array of data values, at least one of which is an instruction pointer. Each member of the ordered array can be indicative of any type of data. As a packet progresses through the pixel shader during processing, each member of the ordered array can be replaced by a sequence of data values indicative of different types of data (e.g., an address of a texel, a texel, or a partially or fully processed color value). Information required for the pixel shader to process each packet is contained in the packet, and thus the pixel shader is scalable in the sense that it can be implemented in modular fashion to include any number of identical pipelined processing stages and can execute the same program regardless of the number of stages. Preferably, each processing stage is itself scalable, can be implemented to include an arbitrary number of identical pipelined instruction execution stages known as microblenders, and can execute the same program regardless of the number of microblenders. The current value of the instruction pointer (IP) in a packet determines the next instruction to be executed on the data contained in the packet. Any processing unit can change the instruction that will be executed by a subsequent processing unit by modifying the IP (and/or condition codes) of a packet that it asserts to the subsequent processing unit. Other aspects of the invention include graphics processors (each including a pixel shader configured in accordance with the invention), methods and systems for generating packets of data for processing in accordance with the invention, and methods for pipelined processing of packets of data.