Here is my solution for Sign Function (probably not the best one):
@loop:
subleq @tmp, @IN
subleq @tmp, @zero, @branch
subleq @OUT, @one
subleq @tmp, @tmp, @loop
@branch:
subleq @tmp2, @tmp
subleq @tmp2, @zero, @out_zero
subleq @OUT, @n_one
subleq @tmp, @tmp, @restart
@out_zero:
subleq @OUT, @zero
subleq @tmp, @tmp, @restart
@restart: subleq @tmp2, @tmp2, @loop
@tmp: .data 0
@tmp2: .data 0
@zero: .data 0
@one: .data 1
@n_one: .data -1