Filter
Top Products
Chapter 3 General 64-Bit Optimizations 59
Software Optimization Guide for AMD64 Processors
25112 Rev. 3.06 September 2005
Chapter 3 General 64-Bit Optimizations
In long mode, the AMD64 architecture provides both a compatibility mode, which allows a 64-bit
operating system to run existing 16-bit and 32-bit applications, and a 64-bit mode, which provides
64-bit addressing and expanded register resources to support higher performance for recompiled
64-bit programs. This chapter presents general optimizations that improve the performance of
software designed to run in 64-bit mode. Therefore, all optimizations in this chapter apply only to
64-bit software.
This chapter covers the following topics:
Topic Page
64-Bit Registers and Integer Arithmetic 60
64-Bit Arithmetic and Large-Integer Multiplication 62
128-Bit Media Instructions and Floating-Point Operations 67
32-Bit Legacy GPRs and Small Unsigned Integers 68