Before You Begin

This manual describes the floating-point environment supported by software and hardware on SPARC and x86 platforms running the Solaris operating system. 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.

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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.

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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 Forte Developer 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 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 or Intel system.

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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 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.	Rdir[:dir]	R/local/libs:/U/a
...	The ellipsis indicates omission in a series.	xinline=f1[,...fn]	xinline=alpha,dos

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Shell Prompts

Shell	Prompt
C shell	%
Bourne shell and Korn shell	$
C shell, Bourne shell, and Korn shell superuser	#

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Accessing Forte Developer Development Tools and Man Pages

The Forte Developer product components and man pages are not installed into the standard /usr/bin/ and /usr/share/man directories. To access the Forte Developer compilers and tools, you must have the Forte Developer component directory in your PATH environment variable. To access the Forte Developer man pages, you must have the Forte Developer man page directory in your MANPATH environment variable.

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 and MANPATH variables to access this Forte Developer release, see the installation guide or your system administrator.

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Note - The information in this section assumes that your Forte Developer products are installed in the /opt directory. If your product software is not installed in the /opt directory, ask your system administrator for the equivalent path on your system.

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Accessing Forte Developer Compilers and Tools

Use the steps below to determine whether you need to change your PATH variable to access the Forte Developer 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: