Learning Malware Analysis

6.4 If-Else Statement

Now, let's try to understand how the if/else statement is translated to assembly language. Let's take an example of the following C code:

if (x == 0) {    x = 5;}else {    x = 1;}

In the preceding code, try to determine under what circumstances the jump would be taken (control would be transferred). There are two circumstances: the jump will be taken to the else block if the x is not equal to 0, or, if x is equal to 0 (if x == 0), then after the execution of x=5 (the end of the if block), a jump will be taken to bypass the else block, to execute the code after the else block.

The following is the assembly translation of the C program; notice that in the first line, the value of x is compared with 0, and the jump (conditional ...