# US 10,768,931 B2 · Fine-grained management of exception enablement of floating point controls

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- Number: US 10,768,931 B2
- Document ID: US10768931B2
- Status: Granted
- Kind: B2
- Application number: 15/812,529
- Filed: 2017-11-14
- Published: 2018-12-27
- Granted: 2020-09-08
- Earliest claimed: 2017-06-23
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Michael K. Gschwind; Valentina Salapura
- Web page: https://patentgrep.com/patent/US10768931B2

## CPC

- G06F 9/3001: {Arithmetic instructions}
- G06F 9/30014: {with variable precision}
- G06F 9/30076: {to perform miscellaneous control operations, e.g. NOP}
- G06F 9/30101: {Special purpose registers}
- G06F 9/30185: {according to one or more bits in the instruction, e.g. prefix, sub-opcode}
- G06F 9/30189: {according to execution mode, e.g. mode flag}
- G06F 9/3861: {Recovery, e.g. branch miss-prediction, exception handling (error detection or correction G06F11/00)}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

Setting or updating of floating point controls is managed. Floating point controls include controls used for floating point operations, such as rounding mode and/or other controls. Further, floating point controls include status associated with floating point operations, such as floating point exceptions and/or others. The management of the floating point controls includes efficiently updating the controls, while reducing costs associated therewith.

## Claims

### Claim 1

A computer-implemented method of facilitating processing within a computing environment, the computer-implemented method comprising:
obtaining a user-specified value for a floating point exception control for a selected instruction to be processed, the floating point exception control indicating a particular event;
determining, based on the user-specified value and another value for the floating point exception control provided by a centralized status exception control, an enablement control for the floating point exception control, wherein the determining comprises combining the user-specified value and the other value to provide a value for the enablement control; and
executing the selected instruction, wherein an indication of a floating point exception associated with execution of the selected instruction is enabled or disabled based on the value of the enablement control.

### Claim 2 (depends on 1)

The computer-implemented method of claim 1, wherein the particular event comprises an event selected from a group consisting of: an overflow, an underflow, an illegal operation, a sticky operation, a Not-a-Number operation, and an imprecise result indication.

### Claim 3 (depends on 1)

The computer-implemented method of claim 1, wherein the enablement control controls whether the floating point exception control provides an indication of the particular event.

### Claim 4 (depends on 1)

The computer-implemented method of claim 1, wherein the centralized status exception control is included in a floating point control register.

### Claim 5 (depends on 1)

The computer-implemented method of claim 1, wherein the user-specified value is provided via an exception control prefix included with the selected instruction.

### Claim 6 (depends on 1)

The computer-implemented method of claim 1, wherein the user-specified value is provided via a prefix instruction added to an instruction stream prior to the selected instruction.

### Claim 7 (depends on 6)

The computer-implemented method of claim 6, wherein the prefix instruction comprises at least one exception control field indicating at least one floating point exception control to be provided by the prefix instruction.

### Claim 8 (depends on 6)

The computer-implemented method of claim 6, wherein the prefix instruction further comprises at least one exception control field value indicating at least one user-specified value for the at least one floating point exception control.

### Claim 9 (depends on 7)

The computer-implemented method of claim 7, wherein the prefix instruction further includes an indicator to specify whether an exception control field of the at least one exception control field is enabled.

### Claim 10 (depends on 1)

The computer-implemented method of claim 1, further comprising:
determining which type of floating point instruction the floating point exception control is to be applied, wherein there is a plurality of types of floating point instructions including at least one of binary, decimal, hexadecimal and vector; and
applying the floating point exception control to the determined type of floating point instruction.