METHOD AND APPARATUS FOR LOOP AND BRANCH INSTRUCTIONS IN A PROGRAMMABLE GRAPHICS PIPELINE

A method and apparatus for executing loop and branch program instructions in a programmable graphics shader. The programmable graphics shader converts a sequence of instructions comprising a portion of a shader program and selects a first set of fragments to be processed. Subsequent sequences of instructions are converted until all of the instructions comprising the shader program have been executed on the first set of fragments. Each remaining set of fragments is processed by the shader program until all of the fragments are processed in the same manner. Furthermore, the instructions can contain one or more loop or branch program instructions that are conditionally executed. Additionally, when instructions within a loop as defined by a loop instruction are being executed a current loop count is pipelined through the programmable graphics shader and used as an index to access graphics memory.