Graphics processor with arithmetic and elementary function units

• US 8,884,972 B2
• Filed: 05/25/2006
• Issued: 11/11/2014
• Est. Priority Date: 05/25/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Du, Yun, Jiao, Guofang, Yu, Chun, Bourd, Alexei V.
• Primary Examiner(s): Crawford, Jacinta M
• Application Number:
  US11/441,696
• Publication Number:
  US 20070273698A1
• Time in Patent Office: 3,092 Days
• Field of Search: 345/522, 345/501, 345/502, 345/505, 345/506, 712/1, 712/216
• US Class Current: 345/502
• CPC Class Codes: G06F 9/30167 of immediate specifier, e.g. constants
• CPC Class Codes: G06F 9/383 Operand prefetching cache prefetching G06F12/0862
• CPC Class Codes: G06F 9/3851 from multiple instruction streams, e.g. multistreaming
• CPC Class Codes: G06F 9/3885 using a plurality of independent parallel functional units
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining

Abstract

A graphics processor capable of efficiently performing arithmetic operations and computing elementary functions is described. The graphics processor has at least one arithmetic logic unit (ALU) that can perform arithmetic operations and at least one elementary function unit that can compute elementary functions. The ALU(s) and elementary function unit(s) may be arranged such that they can operate in parallel to improve throughput. The graphics processor may also include fewer elementary function units than ALUs, e.g., four ALUs and a single elementary function unit. The four ALUs may perform an arithmetic operation on (1) four components of an attribute for one pixel or (2) one component of an attribute for four pixels. The single elementary function unit may operate on one component of one pixel at a time. The use of a single elementary function unit may reduce cost while still providing good performance.

Claims

1. An apparatus comprising:

an output buffer;

at least one arithmetic logic unit (ALU) operative to perform arithmetic operations based on ALU instructions of one thread; and

at least one elementary function unit operative to compute elementary functions based on elementary function unit instructions of the one thread, wherein the at least one elementary function unit and the at least one ALU are independently coupled to the output buffer and are configured to operate on different instructions of the one thread in parallel, and wherein the ALU instructions of the one thread comprise synchronization bits, as part of the ALU instructions of the one thread, that ensure that the ALU instructions of the one thread that are dependent upon the elementary function unit instructions of the one thread follow the elementary function unit instructions of the one thread upon which the ALU instructions of the one thread depend.

2. The apparatus of claim 1, wherein the at least one ALU comprises at least four ALUs.

3. The apparatus of claim 2, wherein the at least four ALUs are operable to perform an arithmetic operation on up to four components of an attribute for a pixel.

4. The apparatus of claim 2, wherein the at least four ALUs are operable to perform an arithmetic operation on a component of an attribute for up to four pixels.

5. The apparatus of claim 1, wherein the at least one ALU comprises more than one ALU, and wherein the at least one elementary function unit comprises fewer elementary function units than ALUs.

6. The apparatus of claim 1, wherein the at least one elementary function unit comprises a single elementary function unit.

7. The apparatus of claim 1, wherein the at least one ALU and the at least one elementary function unit have different latency.

8. The apparatus of claim 1, further comprising:

a load control unit operative to facilitate exchanges of data between the at least one ALU and a memory system and between the at least one elementary function unit and the memory system.

9. The apparatus of claim 8, wherein the at least one elementary function unit is coupled to the load control unit.

10. The apparatus of claim 9, wherein the at least one elementary function unit is operable in parallel with the load control unit.

11. The apparatus of claim 9, wherein requests for the at least one elementary function unit and load requests for the load control unit share a bus, and wherein the at least one elementary function unit and the load control unit are operable to execute different threads in parallel.

12. The apparatus of claim 1, further comprising:

a scheduler operative to receive threads from at least one graphics application and to schedule execution of the threads, one thread at a time, by the at least one ALU and the at least one elementary function unit.

13. The apparatus of claim 12, wherein the at least one elementary function unit is coupled to the scheduler.

14. An integrated circuit comprising:

an output buffer;

at least one arithmetic logic unit (ALU) operative to perform arithmetic operations based on ALU instructions of one thread; and

at least one elementary function unit operative to compute elementary functions based on elementary function unit instructions of the one thread, wherein the at least one elementary function unit and the at least one ALU are independently coupled to the output buffer and are configured to operate on different instructions of the one thread in parallel, and wherein the ALU instructions of the one thread comprise synchronization bits, as part of the ALU instructions of the one thread, that ensure that the ALU instructions of the one thread that are dependent upon the elementary function unit instructions of the one thread follow the elementary function unit instructions of the one thread upon which the ALU instructions of the one thread depend.

15. The integrated circuit of claim 14, wherein the at least one ALU comprises at least four ALUs and fewer than four elementary function units.

16. The integrated circuit of claim 14, wherein the integrated circuit comprises more than one ALU, and wherein the integrated circuit comprises fewer elementary function units than ALUs.

17. The integrated circuit of claim 14, further comprising:

a processing unit that includes the at least one ALU and the at least one elementary function unit.

18. A wireless device comprising:

a graphics processor comprising;

an output buffer;

at least one arithmetic logic unit (ALU) operative to perform arithmetic operations based on ALU instructions of one thread; and

at least one elementary function unit operative to compute elementary functions based on elementary function unit instructions of the one thread, wherein the at least one elementary function unit and the at least one ALU are independently coupled to the output buffer and are configured to operate on different instructions of the one thread in parallel, and wherein the ALU instructions of the one thread comprise synchronization bits, as part of the ALU instructions of the one thread, that ensure that the ALU instructions of the one thread that are dependent upon the elementary function unit instructions of the one thread follow the elementary function unit instructions of the one thread upon which the ALU instructions of the one thread depend; and

a memory system operative to store data for the graphics processor.

19. The wireless device of claim 18, wherein the graphics processor comprises at least four ALUs and fewer than four elementary function units.

20. A method comprising:

performing, with at least one arithmetic logic unit (ALU), arithmetic operations based on ALU instructions of one thread; and

computing, with at least one elementary function unit, elementary functions based on elementary function unit instructions of the one thread;

wherein the ALU and the elementary function unit are independently coupled to an output buffer and operate on different instructions of the one thread in parallel, and

wherein the ALU instructions of the one thread comprise synchronization bits, as part of the ALU instructions of the one thread, that ensure that the ALU instructions of the one thread that are dependent upon the elementary function unit instructions of the one thread follow the elementary function unit instructions of the one thread upon which the ALU instructions of the one thread depend.

21. The method of claim 20, wherein performing arithmetic operations with at least one ALU comprises performing, with at least four ALUs, the arithmetic operations based on the ALU instructions of the one thread.

22. The method of claim 21, wherein performing, with the at least four ALUs, the arithmetic operations comprises performing, with the at least four ALUs, the arithmetic operations on up to four components of an attribute for a pixel.

23. The method of claim 21, wherein performing, with the at least four ALUs, the arithmetic operations comprises performing, with the at least four ALUs, the arithmetic operations on a component of an attribute for up to four pixels.

24. The method of claim 20, wherein performing the arithmetic operations comprises performing, with more than one ALU, the arithmetic operations, and wherein computing elementary functions comprises computing, with fewer elementary function units than ALUs, the elementary functions.

25. The method of claim 20, wherein computing elementary functions comprises computing, with a single elementary function unit, the elementary functions.

26. The method of claim 20, wherein the at least one ALU and the at least one elementary function unit have different latency.

27. The method of claim 20, further comprising:

facilitating, with a load control unit, exchanges of data between the at least one ALU and a memory system, and between the at least one elementary function unit and the memory system.

28. The method of claim 20, further comprising:

receiving, with a scheduler, threads from at least one graphics application, and scheduling, with the scheduler, execution of the threads, one thread at a time, by the at least one ALU and the at least elementary function unit.

29. An apparatus comprising:

an output buffer;

means for performing arithmetic operations based on arithmetic logic unit (ALU) instructions of one thread; and

means for computing elementary functions based on elementary function unit instructions of the one thread,

wherein the means for performing and the means for computing are independently coupled to the output buffer and are configured to operate on different instructions of the one thread in parallel, and

wherein the ALU instructions of the one thread comprise synchronization bits, as part of the ALU instructions of the one thread, that ensure that the ALU instructions of the one thread that are dependent upon the elementary function unit instructions of the one thread follow the elementary function unit instructions of the one thread upon which the ALU instructions of the one thread depend.

30. The apparatus of claim 29, wherein the means for performing comprises at least four ALUs.

31. The apparatus of claim 30, wherein the at least four ALUs are configured to perform an arithmetic operation on up to four components of an attribute for a pixel.

32. The apparatus of claim 30, wherein the at least four ALUs are configured to perform an arithmetic operation on a component of an attribute for up to four pixels.

33. The apparatus of claim 29, wherein the means for performing comprises more than one ALU, and wherein the means for computing comprises fewer elementary function units than ALUs.

34. The apparatus of claim 29, wherein the means for computing comprises a single elementary function unit.

35. The apparatus of claim 29, wherein the means for performing comprises at least one ALU, wherein the means for computing comprises at least one elementary function unit, and wherein the at least one ALU and the at least one elementary function unit have different latency.

36. The apparatus of claim 29, wherein the apparatus comprises one of:

an integrated circuit; and

a wireless device.

37. A non-transitory computer-readable storage medium having stored thereon instructions, when executed, cause one or more processors to:

perform, with at least one arithmetic logic unit (ALU), arithmetic operations based on ALU instructions of one thread; and

compute, with at least one elementary function unit, elementary functions based on elementary function unit instructions of the one thread;

wherein the ALU and the elementary function unit are independently coupled to an output buffer and operate on different instructions of the one thread in parallel, and

wherein the ALU instructions of the one thread comprise synchronization bits, as part of the ALU instructions of the one thread, that ensure that the ALU instructions of the one thread that are dependent upon the elementary function unit instructions of the one thread follow the elementary function unit instructions of the one thread upon which the ALU instructions of the one thread depend.

38. The computer-readable storage medium of claim 37, wherein the instructions that cause the one or more processors to perform arithmetic operations comprise instructions that cause the one or more processors to perform, with at least four ALUs, the arithmetic operations based on the ALU instructions of the one thread.

39. The computer-readable storage medium of claim 38, wherein the instructions that cause the one or more processors to perform, with the at least four ALUs, the arithmetic operations comprise instructions that cause the one or more processors to perform, with the at least four ALUs, the arithmetic operations on up to four components of an attribute for a pixel.

40. The computer-readable storage medium of claim 38, wherein the instructions that cause the one or more processors to perform, with the at least four ALUs, the arithmetic operations comprise instructions that cause the one or more processors to perform, with the at least four ALUs, the arithmetic operations on a component of an attribute for up to four pixels.

41. The computer-readable storage medium of claim 37, wherein the instructions that cause the one or more processors to perform the arithmetic operations comprise instructions that cause the one or more processors to perform, with multiple ALUs, the arithmetic operations, and wherein the instructions that cause the one or more processors to compute elementary functions comprise instructions that cause the one or more processors to compute, with fewer elementary function units than ALUs, the elementary functions.

42. The computer-readable storage medium of claim 37, wherein the instructions that cause the one or more processors to compute elementary functions comprise instructions that cause the one or more processors to compute, with a single elementary function unit, the elementary functions.

43. The computer-readable storage medium of claim 37, wherein the at least one ALU and the at least one elementary function unit have different latency.