Apparatus and method for an enhanced integer divide in an IA64 architecture

• US 6,779,106 B1
• Filed: 09/28/2000
• Issued: 08/17/2004
• Est. Priority Date: 09/28/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Blandy, Geoffrey Owen
• Primary Examiner(s): TSAI, HENRY
• Application Number:
  US09/671,873
• Time in Patent Office: 1,419 Days
• Field of Search: 712/221, 712/222, 712/220, 712/24, 712/23, 712/25, 712/26, 712/244, 708/552, 708/650
• US Class Current: 712/221
• CPC Class Codes: G06F 7/535 Dividing only
• CPC Class Codes: G06F 9/3001 Arithmetic instructions
• CPC Class Codes: G06F 9/30181 Instruction operation extension or modification
• CPC Class Codes: G06F 9/3853 of compound instructions

Abstract

An apparatus and method for performing integer divide operations in an IA64 architecture based data processing system is provided. The apparatus and method insert integer divide checks in place of NOP instructions in the instruction bundles associated with integer divide operations. The checks serve to identify typically encountered integer divide operations. Based on such identifications, the integer divide operation may be short-circuited such that the appropriate result may be returned without having to complete the integer divide operation.

Claims

1. A method of performing an integer divide operation in a data processing device, comprising:

receiving a call to an integer divide routine;

creating instruction bundles for the integer divide routine; and

replacing one or more instructions in the instruction bundles with an integer divide check operation.

2. The method of claim 1, wherein the data processing device has an IA64 architecture.

3. The method of claim 1, wherein the integer divide check operation is one of checking for a positive denominator being greater than a positive numerator, a denominator being equal to the numerator, a positive numerator and a denominator being 10, a divide by 1, and division of powers of 2.

4. The method of claim 1, wherein replacing one or more instructions in the instruction bundles with an integer divide check operation is performed based on a priority order of one or more integer divide check operations.

5. The method of claim 1, wherein the method is implemented in a Java Virtual Machine on the data processing device.

6. The method of claim 1, wherein the integer divide check operation is a check for an integer divide condition that is typically encountered.

7. The method of claim 1, further comprising:

checking the integer divide operation using the integer divide check operation; and

returning a result of the integer divide operation based on a positive outcome of checking the integer divide operation using the integer divide check operation, wherein the result is returned without completing execution of the integer divide routine, and wherein the result is a result that would have been obtained had execution of the integer divide routine been permitted to complete.

8. The method of claim 1, wherein the integer divide check operation short-circuits the integer divide routine when a result of the integer divide check operation is positive, to thereby output a result without completing the execution of the integer divide routine, wherein the result is a result that would have been obtained had execution of the integer divide routine been permitted to complete.

9. The method of claim 1, wherein replacing one or more instructions with an integer divide check operation is performed repeatedly.

10. The method of claim 1, wherein the one or more instructions are NOP instructions.

11. An apparatus for performing an integer divide operation in a data processing device, comprising:

means for receiving a call to an integer divide routine;

means for creating instruction bundles for the integer divide routine; and

means for replacing one or more instructions in the instruction bundles with an integer divide check operation.

12. The apparatus of claim 11, wherein the data processing device has an IA64 architecture.

13. The apparatus of claim 11, wherein the integer divide check operation is one of checking for a positive denominator being greater than a positive numerator, a denominator being equal to the numerator, a positive numerator and a denominator being 10, a divide by 1, and division of powers of 2.

14. The apparatus of claim 11, wherein the means for replacing one or more instructions in the instruction bundles with an integer divide check operation replaces the one or more instructions based on a priority order of one or more integer divide check operations.

15. The apparatus of claim 11, wherein the means for receiving, means for creating and means for replacing are part of a Java Virtual Machine on the data processing device.

16. The apparatus of claim 11, wherein the integer divide check operation is a check for an integer divide condition that is typically encountered.

17. The apparatus of claim 11, further comprising:

means for checking the integer divide operation using the integer divide check operation; and

means for returning a result of the integer divide operation based on a positive outcome of checking the integer divide operation using the integer divide check operation, wherein the result is returned without completing execution of the integer divide routine, and wherein the result is a result that would have been obtained had execution of the integer divide routine been permitted to complete.

18. The apparatus of claim 11, wherein the integer divide check operation short-circuits the integer divide routine when a result of the integer divide check operation is positive, to thereby output a result without completing the execution of the integer divide routine, wherein the result is a result that would have been obtained had execution of the integer divide routine been permitted to complete.

19. The apparatus of claim 11, wherein the means for replacing one or more instructions with an integer divide check operation performs the replacing of the one or more instructions repeatedly.

20. The apparatus of claim 11, wherein the one or more instructions are NOP instructions.

21. A computer program product in a computer readable medium for performing an integer divide operation in a data processing device, comprising:

first instructions for receiving a call to an integer divide routine;

second instructions for creating instruction bundles for the integer divide routine; and

third instructions for replacing one or more instructions in the instruction bundles with an integer divide check operation.

22. The computer program product of claim 21, wherein the data processing device has an IA64 architecture.

23. The computer program product of claim 21, wherein the integer divide check operation is one of checking for a positive denominator being greater than a positive numerator, a denominator being equal to the numerator, a positive numerator and a denominator being 10, a divide by 1, and division of powers of 2.

24. The computer program product of claim 21, wherein the third instructions for replacing one or more instructions in the instruction bundles with an integer divide check operation are executed based on a priority order of one or more integer divide check operations.

25. The computer program product of claim 21, wherein the computer program product is executed in a Java Virtual Machine on the data processing device.

26. The computer program product of claim 21, wherein the integer divide check operation is a check for an integer divide condition that is typically encountered.

27. The computer program product of claim 21, further comprising:

fourth instructions for checking the integer divide operation using the integer divide check operation; and

fifth instructions for returning a result of the integer divide operation based on a positive outcome of checking the integer divide operation using the integer divide check operation, wherein the result is returned without completing execution of the integer divide routine, and wherein the result is a result that would have been obtained had execution of the integer divide routine been permitted to complete.

28. The computer program product of claim 21, wherein the integer divide check operation short-circuits the integer divide routine when a result of the integer divide check operation is positive, to thereby output a result without completing the execution of the integer divide routine, wherein the result is a result that would have been obtained had execution of the integer divide routine been permitted to complete.

29. The computer program product of claim 21, wherein the third instructions for replacing one or more instructions with an integer divide check operation are executed repeatedly.

30. The computer program product of claim 21, wherein the one or more instructions are NOP instructions.