AMD 250 manual Contents

25112 Rev. 3.06 September 2005 Software Optimization Guide for AMD64 Processors

Contents

Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xv Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

1.1	Intended Audience	.1
1.2	Getting Started Quickly	.1
1.3	Using This Guide	.2
1.4	Important New Terms	.4
1.5	Key Optimizations	.6
Chapter 2	C and C++ Source-Level Optimizations	.7
2.1	Declarations of Floating-Point Values	.9
2.2	Using Arrays and Pointers	10
2.3	Unrolling Small Loops	13
2.4	Expression Order in Compound Branch Conditions	14
2.5	Long Logical Expressions in If Statements	16
2.6	Arrange Boolean Operands for Quick Expression Evaluation	17
2.7	Dynamic Memory Allocation Consideration	19
2.8	Unnecessary Store-to-Load Dependencies	20
2.9	Matching Store and Load Size	22
2.10	SWITCH and Noncontiguous Case Expressions	25
2.11	Arranging Cases by Probability of Occurrence	28
2.12	Use of Function Prototypes	29
2.13	Use of const Type Qualifier	30
2.14	Generic Loop Hoisting	31
2.15	Local Static Functions	34
2.16	Explicit Parallelism in Code	35
2.17	Extracting Common Subexpressions	37
2.18	Sorting and Padding C and C++ Structures	39
2.19	Sorting Local Variables	41

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