Beginning x64 Assembly Programming: From Novice to AVX Professional

© Jo Van Hoey 2019

J. Van HoeyBeginning x64 Assembly Programminghttps://doi.org/10.1007/978-1-4842-5076-1_5

5. Assembly Is Based on Logic

Jo Van Hoey¹ 

(1)

Hamme, Belgium

 

It’s time to rehearse some logic theory. Don’t panic, because we will look at only what we need: NOT, OR, XOR, and AND.

In this chapter, 0 means false, and 1 means true.

NOT

A	0	1
NOT A	1	0

Convert every 0 into 1 and every 1 into 0.

Here’s an example:

A =        11001011

NOT A =    00110100

OR

A	0	1	0	1
B	0	0	1	1
A OR B	0	1	1	1

If there is a 1 in A or B or in both, the outcome is a 1.

Here’s an example:

A =        11001011

B =        00011000

A OR B =   11011011

XOR

A	0	1	0	1
B	0	0	1	1
A XOR B	0	1	1	0

Exclusive OR: If there is a 1 in A or B, the outcome is a 1. If A and B are both 1 or 0, the outcome is 0.

Here’s an example: ...