Graphics pipeline token synchronization

• US 6,867,781 B1
• Filed: 11/28/2000
• Issued: 03/15/2005
• Est. Priority Date: 08/23/2000
• Status: Expired due to Term

• Current Assignee: Nintendo Company Limited
• Original Assignee: Nintendo Company Limited
• Inventors: Cheng, Howard H., Van Hook, Timothy J., Moore, Robert, Fouladi, Farhad
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): NGUYEN, HAU H
• Application Number:
  US09/722,419
• Time in Patent Office: 1,568 Days
• Field of Search: 345/506, 345/522, 345/422, 345501-505, 345/556, 712/40, 712/219
• US Class Current: 345/506
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining
• CPC Class Codes: G06T 15/005 General purpose rendering architectures

Abstract

A graphics system including a custom graphics and audio processor produces exciting 2D and 3D graphics and surround sound. The system includes a graphics and audio processor including a 3D graphics pipeline and an audio digital signal processor. The graphics pipeline processes graphics commands at different rates depending upon the type of operation being performed. This makes it difficult to synchronize pipeline operations with external operations (e.g., a graphics processor with a main processor). To solve this problem, a synchronization token including a programmable data message is inserted into a graphics command stream sent to a graphics pipeline. At a predetermined point near the bottom of the pipeline, the token is captured and a signal is generated indicated the token has arrived. The graphics command producer can look at the captured token to determine which of multiple possible tokens has been captured, and can use the information to synchronize a task with the graphics pipeline. Applications include maintaining memory coherence in memory shared between the 3D graphics pipeline and a graphics command producer.

Claims

1. A method of synchronizing at least one process external to a graphics pipeline with the graphics pipeline comprising:

sending a programmable content synchronization token down the graphics pipeline;

detecting when the synchronization token has reached a predetermined point in the pipeline; and

signaling the external process when the synchronization token has been detected to reach said predetermined point in the pipeline.

2. The method of claim 1 wherein the synchronization token comprises a variable content data message the graphics pipeline does not modify.

3. The method of claim 1 wherein the detecting step comprises comparing a value returned by a token register with the value of the sent synchronization token.

4. The method of claim 1 further including specifying, with an application program, a variable synchronization token value to send down the graphics pipeline.

5. The method of claim 1 wherein the synchronization token comprises a 16-bit variable value.

6. The method of claim 1 wherein the detecting step includes polling a synchronization token register at the end of the pipeline in response to an interrupt.

7. A method of synchronizing at least one process external to a graphics pipeline with the graphics pipeline, said graphics pipeline being of the type including a command processor, a transformation unit, a lighting unit, a texture coordinate generator, a texture mapper, a rasterizer, a blender, a pixel engine and a frame buffer, the method comprising:

inserting a variable content synchronization message into the graphics pipeline;

capturing the variable content synchronization message at a predetermined position within the pipeline;

signaling the external process when the variable content synchronization message has reached the predetermined position within the pipeline; and

testing whether the captured variable content synchronization message corresponds to the inserted variable content synchronization message.

8. The method of claim 7 wherein the signaling step comprises generating an interrupt when the variable content synchronization message reaches the bottom of the pipeline.

9. The method of claim 7 wherein the capturing step comprises storing the variable content synchronization message in a register, and the determining step includes reading the contents of the register.

10. The method of claim 7 wherein the pixel engine performs the signaling step.

11. The method of claim 7 wherein the graphics pipeline does not modify the variable content synchronization message.

12. A graphics pipeline including:

a command processor,

a transformation unit,

a lighting unit,

a texture coordinate generator,

a texture mapper,

a rasterizer,

a blender,

a pixel engine, and

a frame buffer,

wherein the command processor receives a variable content synchronization message and passes the variable content synchronization message through the graphics pipeline to the pixel engine, the pixel engine including a register that captures the variable content synchronization message and signals at least one process external to the graphics pipeline when the variable content synchronization message has reached the pixel engine.

13. The graphics pipeline of claim 12 wherein the graphics pipeline does not alter the variable content synchronization message.

14. A graphics system of the type that receives a stream of graphics commands and generates an image based on the graphics command stream, the graphics system being adapted to receive, within the stream of graphics commands, a synchronization token comprising a variable content synchronization message, the graphics system providing a response to an inquiry as to whether portions of the graphics stream earlier in a graphics command sequence with respect to the synchronization token have been processed to allow synchronization of graphics system events with at least one process external to the graphics command stream processing.

15. The graphics system as in claim 14 wherein the graphics system includes an application specific integrated circuit.

16. The graphics system as in claim 14 wherein the graphics system includes a 3D graphics pipeline.

17. A method of synchronizing a process external to a 3D graphics pipeline with the 3D graphics pipeline, the 3D graphics pipeline being of the type including command processing, transformation, lighting, texture coordinate generation, texture mapping, rasterizing, and blending, an improvement comprising:

inserting a variable content synchronizing token into the graphics pipeline; and

signaling the external process upon the token reaching a predetermined point in the graphics pipeline.