anchor.diff:      (emit (make-instance 'jump-instruction :target out))
       (emit out)))
   
  +(define-builtin mezzano.compiler::%fast-fixnum-+ ((lhs rhs) result :early t)
  +  (emit (make-instance 'x86-fake-three-operand-instruction
  +                       :opcode 'lap:add64
  +                       :result result
  +                       :lhs lhs
  +                       :rhs rhs)))
  +
   (define-builtin mezzano.runtime::%fixnum-- ((lhs rhs) result)
     (let ((out (make-instance 'label)))
       (emit (make-instance 'move-instruction
  
positive.code:                        :source value
                         :destination result)))
  
  (define-builtin mezzano.runtime::%fixnum-< ((lhs rhs) result :early t)
    (emit (make-instance 'fixnum-<-instruction
                         :result result
                         :lhs lhs
                         :rhs rhs)))
  
  (defun lower (backend-function early)
    (multiple-value-bind (uses defs)
  
negative.code:                          :source :r8))
      (emit (make-instance 'jump-instruction :target out))
      (emit out)))
  
  (define-builtin mezzano.compiler::%fast-fixnum-- ((lhs rhs) result :early t)
    (emit (make-instance 'x86-fake-three-operand-instruction
                         :opcode 'lap:sub64
                         :result result
                         :lhs lhs
                         :rhs rhs)))
  
  (define-builtin mezzano.runtime::%fixnum-* ((lhs rhs) result)
    (let ((fixnum-result (make-instance 'label))
  