filling all current holes it is envisioned that other triggering events can cause the graphics processor 114 to signal the cpu 102 for example if the difference between a max and a min exceeds a threshold value which may be programmable it is envisioned that signaling mechanisms other than cpu interrupts may cause all holes to be filled either with or without the assistance of driver software when all holes in the command buffer 306 are filled the hole count becomes zero thereby allowing the graphics processor to continue executing command words the command execution module 307 maintains a 34 read pointer 34 which represents the address in the associated command buffer 306 that was most recently read by the graphics processor 114 this address marks the boundary in the command buffer 306 between words that have been read and dispatched to a controller and words that have not yet been read or dispatched when depth inc is added to the command execution module 39 s 307 command depth counter 408 the read pointer advances causing the command execution module 307 to read words from the command buffer 306 and to dispatch them to the appropriate controller e g the fbi controller 302 or the tmu interface 308 in order to ensure the integrity of the data and or commands that have been written to the command buffer 306 but not yet processed by the graphics processor 114 the driver software does not write to addresses past the address stored in the read pointer the driver software writes command data words to successive command buffer addresses beginning at the first address of the command buffer b and continuing.