anchor.diff:         (ratio
           (mezzano.internals.numbers.ratio:ratio-= (rational x) y))
          (short-float
  -        (sys.int::%%short-float-= x (float y 0.0f0)))
  +        (sys.int::%%single-float-= x (float y 0.0f0)))
          (single-float
           (sys.int::%%single-float-= x y))
          (double-float
  
positive.code:        (ratio
          (mezzano.internals.numbers.ratio:ratio-= (rational x) y))
         (short-float
          (sys.int::%%short-float-= x (float y 0.0d0)))
         (single-float
          (sys.int::%%double-float-= x (float y 0.0d0)))
         (double-float
  
negative.code:        (ratio nil)
         (short-float
          (and (fixnum-fits-in-short-float-p x)
               (sys.int::%%short-float-= (float x 0.0s0) y)))
         (single-float
          (and (fixnum-fits-in-single-float-p x)
               (sys.int::%%single-float-= (float x 0.0f0) y)))
  