State parser for a multi-stage graphics pipeline

Abstract

A command parser,is coupled to an incoming data stream to insert an end of state token at the end of a group of state data,and an end of primitive token at the end of a group of primitive data,to create a parsed data stream. The parsed state data stream is transmitted to a state controller,which loads state data,into shadow stages,The state controller,validates a shadow stage,upon receiving an end of state group token. The parsed primitive data,are also transmitted to primitive controllers,The primitive controllers,prevent primitive data from being transmitted into a processing element,responsive to receiving an end of primitive_B token. Upon receiving an end of primitive_E token, the primitive controller,ascertains whether the first shadow stage,has been validated. If it has, the primitive controller,loads the state data,into the working stage,and allows the primitive data,to be transmitted to the processing element,where it is processed in accordance with the state data,in the working stage,In an alternate embodiment, a dirty bit,is used to indicate that the state data,received by the state controller,is identical to previously received state data,The primitive controller,ascertains whether the dirty bit,of the first shadow stage,associated with its processing element,is marked. If the dirty bit,is unmarked, the primitive controller,allows the primitive data,to be processed by the processing element,without delay in accordance with the existing state information in the working registers.