Chapter 5: Bit Wrangling

Overview

Think of this chapter as a continuation of the previous chapter, "Bit Mangling."

This chapter deals with bit wrangling and thus the movement of bits. They can be shifted into oblivion, rotated , and watched going around and around. As Bugs Bunny would say, "Dizzing, ain't it!"

Bit wrangling actually occurs with the rotation and logical and arithmetic shifting of bits within each parallel bit range of packed bits. Just as in the scalar point of view of a similar general-purpose CPU instruction, the bits can be used for masking, base two multiplication and division, and other functionality.

It must be reiterated that you watch the alignment of your data objects in memory very closely. It takes extra overhead to adjust the memory into an aligned state, and it is a lot more efficient to ensure that they are aligned in the first place. Your code will be smaller and faster! This will be made obvious by the sample code included in this chapter.

Workbench Files: \Bench\ x86 \chap05\ project \ platform

                         project

platform    

Shift /Rotations

\prot\

\vc6

   

\vc.net



32.64-Bit 80X86 Assembly Language Architecture
32/64-Bit 80x86 Assembly Language Architecture
ISBN: 1598220020
EAN: 2147483647
Year: 2003
Pages: 191

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