T=d f ld li
V=x
R=-1,1,1
F=(abs(x) > 0) + \
  2*(0 < abs(x)) + \
  4*(abs(x) < 0) + \
  8*(0 > abs(x))
C=fp_greater(fp_abs(x), 0) + \
  2*fp_less(0, fp_abs(x)) + \
  4*fp_less(fp_abs(x), 0) + \
  8*fp_greater(0, fp_abs(x))
