Question

What decimal value will be in eax after this code executes?

   sub eax, eax

   sub ebx, ebx

looptop: cmp ebx, 5

   jge exitloop

   add eax, ebx

   inc ebx

   jmp looptop

exitloop:

Answer 1

Instruction	Step1	Step2	Step3	Step4	Step5	Step6
sub eax, eax	eax –eax =0
sub ebx, ebx	ebx –ebx =0
looptop: cmp ebx, 5	Comparing ebx value with 5	Comparing ebx value with 5	Comparing ebx value with 5	Comparing ebx value with 5	Comparing ebx value with 5	Comparing ebx value with 5
jge exitloop	If 0 is greater than or equal to 5 then jump to “exitloop”	If 1 is greater than or equal to 5 then jump to “exitloop”	If 2 is greater than or equal to 5 then jump to “exitloop”	If 3 is greater than or equal to 5 then jump to “exitloop”	If 4 is greater than or equal to 5 then jump to “exitloop”	If 5 is greater than or equal to 5 then jump to “exitloop” jump to “exitloop”
add eax, ebx	eax = eax +ebx eax = 0+0 à 0	eax = eax +ebx eax = 0+1 à 1	eax = eax +ebx eax = 1+2 à 3	eax = eax +ebx eax = 3+3 à 6	eax = eax +ebx eax = 6+4 à 10
inc ebx	ebx = ebx +1 ebx = 0 +1 à 1	ebx = ebx +1 ebx = 1 +1 à 2	ebx = ebx +1 ebx = 2 +1 à 3	ebx = ebx +1 ebx = 3 +1 à 4	ebx = ebx +1 ebx = 4 +1 à 5
jmp looptop	Jump to looptop	Jump to looptop	Jump to looptop	Jump to looptop	Jump to looptop
exitloop:						exitloop
Decimal value will be in eax after this code executes 10