Which one should be fit for the questions below?

Question

 a. What would be the values of BX and CX after executing the following instruction assuming that BX = 008D and CX = 1A0C before executing the instruction?

XCHG BX, CX

(i)     BX = 008D and CX = 1A0C

(ii)   BX = 1A0C and CX = 1A0C

(iii)  BX = 1A0C and CX = 008D

(iv)  BX = 008D and CX = 008D

b. What would be the value of ECX after executing the following instruction considering ECX = 00000084 before executing the instruction?

 IMUL ECX, 2

ECX = 00000168

ECX = 00000108

ECX = 00000264

ECX = 00000084

Answer 1

The 'xchg bx,cx' instruction will exchange the values in register bx and cx so, given that the value of bx == x008b and cx == x1a0c beforehand, afterwards their values will be x1a0c and x008b, respectively. The answer is (iii).

The 'imul ecx,2' intruction is an integer multiply, in which the contents of register ecx is replaced by its original value (x00000084) multiplied by 2, for a product of x00000108. The answer is ECX = 00000108.