Question

Can someone please explain in simple terms how the AND, SHL and CMP commands work? Thanks.

Answer 1

AND – One 0 bit means 0 as a result

1 And 0 = 0
0 And 1 = 0
1 And 1 = 1

5 AND 3
0101 AND 0011 (binary)

     0101
AND  0011
     ----
     0001

SHL – Shift Left

SHL EAX, 1 -> shift left one bit

SHL 5, 1 -> 5 is 0101 in binary, so if one shift left it becomes 1010(A)

CMP – Compare, it’s general purpose and depends on cpu eflags.

CMP EAX,5
JE wherever   (if eax equals 5, the zero flag is set and jump is made)