eax

I know that test instruction in assembly language is same as and instruction excpet that destination in previous instruction doesnot effected.


But i dont understand the usage of "test instruction" ,

please if possible give me an example of its usage.

Kaja Fumei

It is a lot like the "cmp" instruction and is often found right before a conditional jump. The difference is the "cmp" instruction uses subtraction to compare them and set the flags while test uses a bitwise AND.

The most common usage of test is to see if a value is 0 or not:

Narue

>But i dont understand the usage of "test instruction"
'test a,b' is identical to 'and a,b' except that test doesn't write the result to a. The usage reflects that. test is used when all you care about is how the flags are set after the operation.

__________________
Even if the voices aren't real, they have some pretty good ideas.