Before You Begin

This manual describes the floating-point environment supported by software and hardware on SPARC^® based systems and x86 based systems running the Solaris Operating System (Solaris OS). Although this manual discusses some general aspects of the SPARC and Intel architectures, it is primarily a reference manual designed to accompany Sun language products.

Certain aspects of the IEEE Standard for Binary Floating-Point Arithmetic are discussed in this manual. To learn about IEEE arithmetic, see the 18-page Standard. See Appendix F for a brief bibliography on IEEE arithmetic.

Who Should Use This Book

This manual is written for those who develop, maintain, and port mathematical and scientific applications or benchmarks. Before using this manual, you should be familiar with the programming language used (Fortran, C, etc.), dbx (the source-level debugger), and the operating system commands and concepts.

How This Book Is Organized

Chapter 1 introduces the floating-point environment.

Chapter 2 describes the IEEE arithmetic model, IEEE formats, and underflow.

Chapter 3 describes the mathematics libraries provided with the Sun Studio compilers.

Chapter 4 describes exceptions and shows how to detect, locate, and handle them.

Appendix A contains example programs.

Appendix B describes the floating-point hardware options for SPARC based workstations.

Appendix C lists x86 and SPARC compatibility issues related to the floating-point units used in Intel systems.

Appendix D is an edited reprint of a tutorial on floating-point arithmetic by David Goldberg.

Appendix E discusses standards compliance.

Appendix F includes a list of references and related documentation.

Glossary contains a definition of terms.

The examples in this manual are in C and Fortran, but the concepts apply to either compiler on a SPARC based or x86 based system.

Typographic Conventions

TABLE P-1 Typeface Conventions
Typeface	Meaning	Examples
`AaBbCc123`	The names of commands, files, and directories; on-screen computer output	Edit your `.login` file. Use `ls` `-a` to list all files. `% You have mail.`
`AaBbCc123`	What you type, when contrasted with on-screen computer output	`%` `su` `Password:`
AaBbCc123	Book titles, new words or terms, words to be emphasized	Read Chapter 6 in the User's Guide. These are called class options. You must be superuser to do this.
AaBbCc123	Command-line placeholder text; replace with a real name or value	To delete a file, type `rm` filename.

TABLE P-2 Code Conventions
Code Symbol	Meaning	Notation	Code Example
[ ]	Brackets contain arguments that are optional.	`O[`n`]`	`O4, O`
{ }	Braces contain a set of choices for a required option.	`d{y\|n}`	`dy`
\|	The "pipe" or "bar" symbol separates arguments, only one of which may be chosen.	`B{dynamic\|static}`	`Bstatic`
:	The colon, like the comma, is sometimes used to separate arguments.	`R`dir`[:`dir`]`	`R/local/libs:/U/a`
...	The ellipsis indicates omission in a series.	`xinline=`f1`[`,...fn`]`	`xinline=alpha,dos`

Shell Prompts

Shell	Prompt
C shell	machine-name`%`
C shell superuser	machine-name`#`
Bourne shell and Korn shell	`$`
Superuser for Bourne shell and Korn shell	`#`

Supported Platforms

This Sun Studio release supports systems that use the SPARC^® and x86 families of processor architectures: UltraSPARC^®, SPARC64, AMD64, Pentium, and Xeon EM64T. The supported systems for the version of the Solaris Operating System you are running are available in the hardware compatibility lists at http://www.sun.com/bigadmin/hcl. These documents cite any implementation differences between the platform types.

In this document, the term "x86" refers to 64-bit and 32-bit systems manufactured using processors compatible with the AMD64 or Intel Xeon/Pentium product families. For supported systems, see the hardware compatibility lists.

Accessing Sun Studio Software and Man Pages

The Sun Studio software and its man pages are not installed into the standard /usr/bin/ and /usr/share/man directories. To access the software, you must have your PATH environment variable set correctly (see Accessing the Software). To access the man pages, you must have the your MANPATH environment variable set correctly (see Accessing the Man Pages.).

For more information about the PATH variable, see the csh(1), sh(1), and ksh(1) man pages. For more information about the MANPATH variable, see the man(1) man page. For more information about setting your PATH variable and MANPATH variables to access this release, see the installation guide or your system administrator.

Note - The information in this section assumes that your Sun Studio compilers and tools are installed in the /opt directory. If your software is not installed in the /opt directory, ask your system administrator for the equivalent path on your system.

Accessing the Software

Use the steps below to determine whether you need to change your PATH variable to access the compilers and tools.

To Determine Whether You Need to Set Your `PATH` Environment Variable

1. Display the current value of the PATH variable by typing the following at a command prompt.

% echo $PATH

2. Review the output to find a string of paths that contain /opt/SUNWspro/bin/.

If you find the path, your PATH variable is already set to access the compilers and tools. If you do not find the path, set your PATH environment variable by following the instructions in the next procedure.

To Set Your `PATH` Environment Variable to Enable Access to the Compilers and Tools

Add the following to your PATH environment variable. If you have Forte Developer software, Sun ONE Studio software, or another release of Sun Studio software installed, add the following path before the paths to those installations.

/opt/SUNWspro/bin

Accessing the Man Pages

Use the following steps to determine whether you need to change your MANPATH variable to access the man pages.

To Determine Whether You Need to Set Your `MANPATH` Environment Variable

1. Request the dbx man page by typing the following at a command prompt.

% man dbx

2. Review the output, if any.

If the dbx(1) man page cannot be found or if the man page displayed is not for the current version of the software installed, follow the instructions in the next procedure for setting your MANPATH environment variable.

To Set Your `MANPATH` Environment Variable to Enable Access to the Man Pages

1. If you are using the C shell, edit your home .cshrc file. If you are using the Bourne shell or Korn shell, edit your home .profile file.

2. Add the following to your MANPATH environment variable.

/opt/SUNWspro/man

Accessing the Integrated Development Environment

The Sun Studio integrated development environment (IDE) provides modules for creating, editing, building, debugging, and analyzing the performance of a C, C++, or Fortran application.

The command to start the IDE is sunstudio. For details on this command, see the sunstudio(1) man page.

The correct operation of the IDE depends on the IDE being able to find the core platform. The sunstudio command looks for the core platform in two locations:

The command looks first in the default installation directory, /opt/netbeans/3.5V.

If the command does not find the core platform in the default directory, it assumes that the directory that contains the IDE and the directory that contains the core platform are both installed in or mounted to the same location. For example, on Solaris platforms, if the path to the directory that contains the IDE is /foo/SUNWspro, the command looks for the core platform in /foo/netbeans/3.5V.

If the core platform is not installed or mounted to either of the locations where the sunstudio command looks for it, then each user on a client system must set the environment variable SPRO_NETBEANS_HOME to the location where the core platform is installed or mounted (/installation_directory/netbeans/3.5V).

Each user of the IDE also must add /installation_directory/SUNWspro/bin to their $PATH in front of the path to any other release of Forte Developer software, Sun ONE Studio software, or Sun Studio software.

The path /installation_directory/netbeans/3.5V/bin should not be added to the user's $PATH.

Accessing Sun Studio Documentation

You can access the documentation at the following locations:

The documentation is available from the documentation index that is installed with the software on your local system or network at file:/opt/SUNWspro/docs/index.html.

If your software is not installed in the /opt directory, ask your system administrator for the equivalent path on your system.

Most manuals are available from the docs.sun.com^sm web site. The following titles are available through your installed software only:

Standard C++ Library Class Reference

Standard C++ Library User's Guide

Tools.h++ Class Library Reference

Tools.h++ User's Guide

The release notes are available from the docs.sun.com web site.

Online help for all components of the IDE is available through the Help menu, as well as through Help buttons on many windows and dialogs, in the IDE.

The docs.sun.com web site (http://docs.sun.com) enables you to read, print, and buy Sun Microsystems manuals through the Internet. If you cannot find a manual, see the documentation index that is installed with the software on your local system or network.

Note - Sun is not responsible for the availability of third-party web sites mentioned in this document. Sun does not endorse and is not responsible or liable for any content, advertising, products, or other materials that are available on or through such sites or resources. Sun will not be responsible or liable for any actual or alleged damage or loss caused by or in connection with use of or reliance on any such content, goods, or services available on or through any such sites or resources.

Documentation in Accessible Formats

The documentation is provided in accessible formats that are readable by assistive technologies for users with disabilities. You can find accessible versions of documentation as described in the following table. If your software is not installed in the /opt directory, ask your system administrator for the equivalent path on your system.

Type of Documentation	Format and Location of Accessible Version
Manuals (except third-party manuals)	HTML at `http://docs.sun.com`
Third-party manuals: Standard C++ Library Class Reference Standard C++ Library User's Guide Tools.h++ Class Library Reference Tools.h++ User's Guide	HTML in the installed software through the documentation index at `file:/opt/SUNWspro/docs/index.html`
Readmes and man pages	HTML in the installed software through the documentation index at `file:/opt/SUNWspro/docs/index.html`
Online help	HTML available through the Help menu in the IDE
Release notes	HTML at `http://docs.sun.com`

Accessing Related Solaris Documentation

The following table describes related documentation that is available through the docs.sun.com web site.

Document Collection	Document Title	Description
Solaris Reference Manual Collection	See the titles of man page sections.	Provides information about the Solaris operating environment.
Solaris Software Developer Collection	Linker and Libraries Guide	Describes the operations of the Solaris link-editor and runtime linker.
Solaris Software Developer Collection	Multithreaded Programming Guide	Covers the POSIX® and Solaris threads APIs, programming with synchronization objects, compiling multithreaded programs, and finding tools for multithreaded programs.

Resources for Developers

Visit http://developers.sun.com/prodtech/cc to find these frequently updated resources:

Articles on programming techniques and best practices

A knowledge base of short programming tips

Documentation of compilers and tools components, as well as corrections to the documentation that is installed with your software

Information on support levels

User forums

Downloadable code samples

New technology previews

You can find additional resources for developers at http://developers.sun.com.

Contacting Sun Technical Support

If you have technical questions about this product that are not answered in this document, go to:

http://www.sun.com/service/contacting

Sun Welcomes Your Comments

Sun is interested in improving its documentation and welcomes your comments and suggestions. Submit your comments to Sun at this URL

http://www.sun.com/hwdocs/feedback

Please include the part number (819-0499-10) of your document.