pushl	%ebp
movl	%esp,%ebp

#i've to do ((X/2)*K1)

movl	%ebx,-12(%ebp)		#X to stack
movl	$2,-8(%ebp)		#2 to stack
movl	K1,%eax			
movl	%eax,-4(%ebp)		#K1 to stack

fildl	-12(%ebp)
fildl	-8(%ebp)
fildl	-4(%ebp)
fdivp	%st(0),%st(1)		#X/2
fmulp	%st(0),%st(1)		#(X/2)*K1

fist	-4(%ebp)
movl	-4(%ebp),%eax		#result to eax casted as int
popl	%ebp

ret