anchor.diff:      (setf (flag-p :of) (and (eq neg1 (negative-p value2 is-word)) (not (eq neg1 (negative-p sum is-word)))))
       sum))
   
  +(defun set-pf-on-op (value)
  +  (setf (flag-p :pf) (evenp (logcount (logand #xff value))))
  +  value)
  +
   (defun set-sf-on-op (value is-word)
     (setf (flag-p :sf) (negative-p value is-word))
     value)
  
positive.code: 
  ;;; Opcode parsing
  
  (defun in-paired-byte-block-p (opcode block)
    (= (truncate (/ opcode 2)) (/ block 2)))
  
  (defun in-4-byte-block-p (opcode block)
    (= (truncate (/ opcode 4)) (/ block 4)))
  
  (defun in-8-byte-block-p (opcode block)
    (= (truncate (/ opcode 8)) (/ block 8)))
  
  (defun in-6-byte-block-p (opcode block)
    (and (= (truncate (/ opcode 8)) (/ block 8)) (< (mod opcode 8) 6)))
  
  (defun parse-opcode (opcode)
    "Parse an opcode."
  
negative.code:     ((in-paired-byte-block-p opcode #x74) (jmp-short-conditionally opcode (flag-p :zf) "z"))
      ((in-paired-byte-block-p opcode #x76) (jmp-short-conditionally opcode (or (flag-p :cf) (flag-p :zf)) "be"))
      ((in-paired-byte-block-p opcode #x78) (jmp-short-conditionally opcode (flag-p :sf) "s"))
      ((in-paired-byte-block-p opcode #x7a) (jmp-short-conditionally opcode (flag-p :pf) "p"))
      ((in-paired-byte-block-p opcode #x7c) (jmp-short-conditionally opcode (not (eq (flag-p :of) (flag-p :sf))) "l"))
      ((in-paired-byte-block-p opcode #x7e) (jmp-short-conditionally opcode (or (flag-p :zf) (not (eq (flag-p :of) (flag-p :sf)))) "le"))
      ((= opcode #xe8) (call-near))
  