anchor.diff:  ;;; element to be read.  The third input is assumed to be an unboxed
   ;;; BIT to be stored as an element in the array.
   
  -(defclass bit-aset-instruction (instruction one-successor-mixin)
  +(defclass bit-aset-instruction
  +    (instruction one-successor-mixin side-effect-mixin)
     ())
   
   (defun make-bit-aset-instruction (input1 input2 input3 successor)
  
positive.code: ;;; element to be read.  The third input is assumed to be an unboxed
  ;;; SHORT-FLOAT to be stored as an element in the array.
  
  (defclass short-float-aset-instruction (instruction one-successor-mixin)
    ())
  
  (defun make-short-float-aset-instruction (input1 input2 input3 successor)
  
negative.code: ;;; the element to be read.  The third input is assumed to be an
  ;;; unboxed (UNSIGNED-BYTE 8) to be stored as an element in the array.
  
  (defclass unsigned-byte-8-aset-instruction
      (instruction one-successor-mixin side-effect-mixin)
    ())
  
  (defun make-unsigned-byte-8-aset-instruction (input1 input2 input3 successor)
  