What is the meaning of XOR in x86 assembly?

assembly xor

Chiggins · Jan 20, 2011 · Viewed 92.8k times · Source

I'm getting into assembly and I keep running into xor, for example:

xor     ax, ax

Does it just clear the register's value?

Answer

A XOR B in english would be translated as "are A and B not equal". So xor ax, ax will set ax to zero since ax is always equal to itself.

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