anchor.diff:  ;;; This instruction takes two inputs which must be values of type
   ;;; unboxed SINGLE-FLOAT.  It has a single output which is the
   ;;; unbox product of the two inputs.
  -;;;
  -;;; This instruction can be used by implementations that support the
  -;;; SINGLE-FLOAT data type.
   
   (defclass single-float-mul-instruction (instruction one-successors-mixin)
     ())
  
positive.code: ;;; This instruction takes two inputs which must be values of type
  ;;; unboxed SINGLE-FLOAT.  It has a single output which is the
  ;;; unbox difference between the two inputs.
  ;;;
  ;;; This instruction can be used by implementations that support the
  ;;; SINGLE-FLOAT data type.
  
  (defclass single-float-sub-instruction (instruction one-successors-mixin)
    ())
  
negative.code: ;;; This instruction takes two inputs which must be values of type
  ;;; unboxed SINGLE-FLOAT.  It has a single output which is the
  ;;; unbox quotient of the two inputs.
  
  (defclass single-float-div-instruction (instruction one-successors-mixin)
    ())
  