anchor.diff:  ;;; Instruction SIMPLE-SINGLE-FLOAT-ASET-INSTRUCTION.
   ;;;
   ;;; This instruction takes three inputs.  The first input is assumed
  -;;; to be a simple array specialized to SIMPLE-SINGLE-FLOAT.  The
  -;;; second is assumed to be a FIXNUM and represents the index in the
  -;;; instance of the element to be read.  The third input is assumed to
  -;;; be an unboxed SIMPLE-SINGLE-FLOAT to be stored as an element in
  -;;; the array.
  +;;; to be a simple array specialized to SINGLE-FLOAT.  The second is
  +;;; assumed to be a FIXNUM and represents the index in the instance of
  +;;; the element to be read.  The third input is assumed to be an
  +;;; unboxed SINGLE-FLOAT to be stored as an element in the array.
   
   (defclass simple-single-float-aset-instruction
       (instruction one-successor-mixin side-effect-mixin)
  
positive.code: 
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Instruction DOUBLE-FLOAT-AREF-INSTRUCTION.
  ;;;
  ;;; This instruction takes two inputs.  The first input is assumed
  
negative.code: ;;; Instruction SIMPLE-SINGLE-FLOAT-AREF-INSTRUCTION.
  ;;;
  ;;; This instruction takes two inputs.  The first input is assumed to
  ;;; be a simple array specialized to SINGLE-FLOAT.  The second is
  ;;; assumed to be a FIXNUM and represents the index in the instance of
  ;;; the element to be read.  This instruction produces a single
  ;;; output, the element read, which is an unboxed SINGLE-FLOAT.
  
  (defclass simple-single-float-aref-instruction
      (instruction one-successor-mixin)
  