anchor.diff:    (emit-xor out reg reg 2))
   
   (define (emit-push out reg)
  -  (emit out "push~A ~A" usual-size-suffix (value-sized reg)))
  +  (emit out "push~A ~A" value-insn-size-suffix (value-sized reg)))
   
   (define (emit-pop out reg)
  -  (emit out "pop~A ~A" usual-size-suffix (value-sized reg)))
  +  (emit out "pop~A ~A" value-insn-size-suffix (value-sized reg)))
   
   (define (emit-set out cc reg)
     (emit out "set~A ~A" cc (funcall reg 0)))
  
positive.code:   (quasiquote
      (define ((unquote name) out . scale)
        (emit out "~A~A" (unquote insn)
              (elt insn-size-suffix (if scale (car scale) value-scale))))))
  
  (define-insn-0 emit-rep-movs "rep ; movs")
  (define-insn-0 emit-pushf "pushf")
  
negative.code: (define (emit-insn-1 out insn oper scale)
    (unless scale
      (set! scale value-scale))
    (emit out "~A~A ~A" insn (insn-size-suffix scale) (funcall oper scale)))
  
  (define-insn-1 emit-neg "neg")
  (define-insn-1 emit-idiv "idiv")
  