Inside Macintosh: PowerPC Numerics /

Preface - About This Book

This book, Inside Macintosh: PowerPC Numerics, is the reference for the PowerPC Numerics environment. PowerPC Numerics is an environment in which floating-point operations are performed quickly and as accurately as possible. The PowerPC Numerics environment applies to Macintosh computers that use the PowerPC processor. The core features of PowerPC Numerics are not exclusive to Apple Computer; rather they are taken from IEEE Standard 754 for binary floating-point arithmetic and the standard proposed by the Floating-Point C Extensions (FPCE) branch of the Numerical C Extensions Group (ANSI X3J11.1).

In one sense, PowerPC Numerics is an abstraction: a definition of an environment for computer numerics, independent of a specific computer. To have an instance of this environment, you need a language in which to describe operations and an implementation unit to carry them out. The first part of this book describes the PowerPC Numerics definition, and the remaining parts describe how numerics is implemented in the PowerPC hardware and software.

You should read this book if

• you want to create PowerPC applications that use floating-point operations
• you have created a 680x0 application that uses floating-point operations and you plan to port it to PowerPC processor-based Macintosh computers (in this case, you might want to read Appendix A, "SANE Versus PowerPC Numerics," first)
• you have not yet created a floating-point application, but you want to learn more about IEEE Standard 754 for binary floating-point arithmetic

This book is not for you if you don't plan to port your 680x0 applications to the PowerPC environment. Applications that are 680x0 based will run on PowerPC processor-based Macintosh computers without rebuilding, but they use the Standard Apple Numerics Environment (SANE) in emulation instead of PowerPC Numerics. You should refer to the Apple Numerics Manual, second edition, which describes SANE.

Before reading this book, you should already be familiar with the PowerPC run-time architecture as described in Inside Macintosh: PowerPC System Software.