PGI User's Guide

PrefaceThere are a wide variety of x86-compatible processors in use. All are supported by the PGI compilers andtools. Most of these processors are forward-compatible, but not backward-compatible, meaning that codecompiled to target a given processor will not necessarily execute correctly on a previous-generation processor.A table listing the processor options that PGI supports is available in the Release Notes. The table also includesthe features utilized by the PGI compilers that distinguish them from a compatibility standpoint.In this manual, the convention is to use "x86" to specify the group of processors that are "32-bit" but not "64-bit." The convention is to use "x64" to specify the group of processors that are both "32-bit" and "64-bit." x86processor-based systems can run only 32-bit operating systems. x64 processor-based systems can run either32-bit or 64-bit operating systems, and can execute all 32-bit x86 binaries in either case. x64 processorshave additional registers and 64-bit addressing capabilities that are utilized by the PGI compilers and toolswhen running on a 64-bit operating system. The prefetch, SSE1, SSE2 and SSE3 processor features furtherdistinguish the various processors. Where such distinctions are important with respect to a given compileroption or feature, it is explicitly noted in this manual.NoteThe default for performing scalar floating-point arithmetic is to use SSE instructions on targets thatsupport SSE1 and SSE2.Related PublicationsThe following documents contain additional information related to the x86 and x64 architectures, and thecompilers and tools available from The Portland Group.• PGI Fortran Reference manual describes the F2003, FORTRAN 77, Fortran 90/95, and HPF statements, datatypes, input/output format specifiers, and additional reference material related to use of the PGI Fortrancompilers.• System V Application Binary Interface Processor Supplement by AT&T UNIX System Laboratories, Inc.(Prentice Hall, Inc.).• System V Application Binary Interface X86-64 Architecture Processor Supplement, www.x86-64.org/abi.pdf.• Fortran 95 Handbook Complete ISO/ANSI Reference, Adams et al, The MIT Press, Cambridge, Mass, 1997.• Programming in VAX Fortran, Version 4.0, Digital Equipment Corporation (September, 1984).• IBM VS Fortran, IBM Corporation, Rev. GC26-4119.• The C Programming Language by Kernighan and Ritchie (Prentice Hall).• C: A Reference Manual by Samuel P. Harbison and Guy L. Steele Jr. (Prentice Hall, 1987).• The Annotated C++ Reference Manual by Margaret Ellis and Bjarne Stroustrup, AT&T Bell Laboratories,Inc. (Addison-Wesley Publishing Co., 1990).• OpenMP Application Program Interface, Version 2.5 May 2005 (OpenMP Architecture Review Board,1997-2005).xix