Program to find the cube root of a number

org 0h
mov r0,#30h
mov a,@r0
mov r1,#00h
mov r1,#6
up:inc r3
subb a,r1
jc last
mov r2,a
mov b,#2
mov a,r1
mul ab
mov r1,a
mov a,r2
sjmp up
last:mov 40h,r3
sjmp $
end