What answer should be fit for the question below?

Question

What would be the values of EAX and EDX after executing the following instruction considering the fact that EAX = 00000096, EBX = 00000005, and EDX = 00000000 before the executing the instruction?

DIV EBX 

(i) EAX = 00000019 and EDX = 00000010 

(ii) EAX = 00000019 and EDX = 00000000 

(iii) EAX = 0000001E and EDX = 00000010 

(iv) EAX = 0000001E and EDX = 00000000

Answer 1

Let's look at what the DIV instruction does in Assembly.

When you use a 32 bit register as the parameter (as in DIV EBX), it assumes that you have the dividend (the number being divided) stitched across the registers EDX:EAX. This means that when you use the divide instruction, it'll do this:

EDX:EAX ________

EBX or EBX|EDX:EAX

Then, after it divides the two numbers, it puts the quotient into EAX and the remainder into EDX. Taking the question into mind, the DIV EBX instruction is asking us to divide 96h by 5h.

96h is 150d

5h is 5d

So we're dividing 150 by 5, which is 30 with no remainder. After converting 30d to hex, that's 1Eh, and the remainder would be 0.