Floating point instruction with selectable comparison attributes

Patent metadata

Field	Value
Publication number	US-9785435-B1
Application number	US-201615335914-A
Country	US
Kind code	B1
Filing date	Oct 27, 2016
Priority date	Oct 27, 2016
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

An instruction to perform a comparison of a first value and a second value is executed. Based on a control of the instruction, a compare function to be performed is determined. The compare function is one of a plurality of compare functions configured for the instruction, and the compare function has a plurality of options for comparison. A compare option based on the first value and the second value is selected from the plurality of options defined for the compare function, and used to compare the first value and the second value. A result of the comparison is then placed in a select location, the result to be used in processing within a computing environment.

First claim

What is claimed is:

1. A computer program product for facilitating processing within a computing environment, the computer program product comprising:
a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:
obtaining an instruction to be executed, the instruction to perform a comparison of a first value and a second value; and
executing the instruction, the executing including:
determining, based on a control of the instruction, a compare function to be performed, wherein the compare function is one of a plurality of different types of compare functions configured for the instruction, the plurality of different types of compare functions including a plurality of techniques for at least one type of compare operation, and wherein the compare function has a plurality of options for comparison;
selecting, from the plurality of options for the compare function, a compare option to be used to compare the first value and the second value, the compare option selected based on the first value and the second value;
comparing the first value and the second value using the compare option to obtain a result, the result specific for the compare option selected for the compare function indicated by the control of the instruction; and
placing the result in a select location, the result to be used in processing within the computing environment.

2. The computer program product of claim 1 , wherein the plurality of options include a plurality of pairs of particular cases selectable for comparison.

3. The computer program product of claim 2 , wherein the plurality of pairs of particular cases include at least one pair of particular cases that includes at least one particular case selected from the group of particular cases comprising: an infinity, a not-a-number (NAN), and a signed zero.

4. The computer program product of claim 1 , wherein the plurality of different types of compare functions include at least one of a plurality of different types of maximum functions and a plurality of different types of minimum functions.

5. The computer program product of claim 4 , wherein the plurality of different types of maximum functions comprise a plurality of maximum techniques to perform a maximum comparison.

6. The computer program product of claim 4 , wherein the plurality of different types of minimum functions comprise a plurality of minimum techniques to perform a minimum comparison.

7. The computer program product of claim 1 , wherein the first value and the second value are provided by the instruction, and wherein the first value is of one element of an operand of the instruction and the second value is of a corresponding element of another operand of the instruction.

8. The computer program product of claim 7 , wherein a size of the one element is determined based on another control of the instruction.

9. The computer program product of claim 8 , wherein the first value and the second value are floating point values, and the size of the one element depends on a floating point format of the floating point values, and wherein the other control indicates a selected floating point format.

10. The computer program product of claim 1 , wherein the control is provided in a mask of the instruction.

11. A computer system for facilitating processing within a computing environment, the computer system comprising:
a memory; and
a processor in communication with the memory, wherein the computer system is configured to perform operations comprising:
obtaining an instruction to be executed, the instruction to perform a comparison of a first value and a second value; and
executing the instruction, the executing including:
determining, based on a control of the instruction, a compare function to be performed, wherein the compare function is one of a plurality of different types of compare functions configured for the instruction, the plurality of different types of compare functions including a plurality of techniques for at least one type of compare operation, and wherein the compare function has a plurality of options for comparison;
selecting, from the plurality of options for the compare function, a compare option to be used to compare the first value and the second value, the compare option selected based on the first value and the second value;
comparing the first value and the second value using the compare option to obtain a result, the result specific for the compare option selected for the compare function indicated by the control of the instruction; and
placing the result in a select location, the result to be used in processing within the computing environment.

12. The computer system of claim 11 , wherein the plurality of options include a plurality of pairs of particular cases selectable for comparison.

13. The computer system of claim 11 , wherein the plurality of different types of compare functions include at least one of a plurality of different types of maximum functions and a plurality of different types of minimum functions.

14. The computer system of claim 11 , wherein the first value and the second value are provided by the instruction, and wherein the first value is of one element of an operand of the instruction and the second value is of a corresponding element of another operand of the instruction.

15. The computer system of claim 14 , wherein a size of the one element is determined based on another control of the instruction, and wherein the first value and the second value are floating point values, and the size of the one element depends on a floating point format of the floating point values, and wherein the other control indicates a selected floating point format.

16. A computer-implemented method of facilitating processing within a computing environment, the computer-implemented method comprising:
obtaining, by at least one processor, an instruction to be executed, the instruction to perform a comparison of a first value and a second value; and
executing the instruction, the executing including:
determining, based on a control of the instruction, a compare function to be performed, wherein the compare function is one of a plurality of different types of compare functions configured for the instruction, the plurality of different types of compare functions including a plurality of techniques for at least one type of compare operation, and wherein the compare function has a plurality of options for comparison;
selecting, from the plurality of options for the compare function, a compare option to be used to compare the first value and the second value, the compare option selected based on the first value and the second value;
comparing the first value and the second value using the compare option to obtain a result, the result specific for the compare option selected for the compare function indicated by the control of the instruction; and
placing the result in a select location, the result to be used in processing within the computing environment.

17. The computer-implemented method of claim 16 , wherein the plurality of options include a plurality of pairs of particular cases selectable for comparison.

18. The computer-implemented method of claim 16 , wherein the plurality of different types of compare functions include at least one of a plurality of different types of maximum functions and a plurality of different types of minimum functions.

19. The computer-implemented method of claim 16 , wherein the first

Assignees

• IBM

Inventors

• Bradbury Jonathan D
• Gschwind Michael K
• Mueller Silvia Melitta
• Olsson Brett
• Schwarz Eric M

Classifications

• G06F7/49926

  Division by zero · CPC title

• G06F9/30185

  according to one or more bits in the instruction, e.g. prefix, sub-opcode · CPC title

• G06F7/49957

  Implementation of IEEE-754 Standard · CPC title

• G06F9/30094

  Condition code generation, e.g. Carry, Zero flag · CPC title

• G06F9/30021 Primary

  Compare instructions, e.g. Greater-Than, Equal-To, MINMAX · CPC title