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Chapter 8

Integer Optimizations

159

Software Optimization Guide for AMD64 Processors

25112

Rev. 3.06

September 2005

Chapter 8

Integer Optimizations

The optimizations in this chapter help improve integer performance.

This chapter covers the following topics:

Topic

Page

Replacing Division with Multiplication

Alternative Code for Multiplying by a Constant

Repeated String Instructions

Using XOR to Clear Integer Registers

Efficient 64-Bit Integer Arithmetic in 32-Bit Mode

Efficient Implementation of Population-Count Function in 32-Bit Mode

Efficient Binary-to-ASCII Decimal Conversion

Derivation of Algorithm, Multiplier, and Shift Factor for Integer Division by Constants

Optimizing Integer Division