anchor.diff:      (txs)
   
       ;; Initialize music player.
  -    ;;(lda (imm 0))                       ; song 0
  -    ;;(ldx (imm 0))                       ; NTSC
  -    ;;(jsr music-init)
  +    ;;  ...or don't.
   
       ;; Init sound hardware
       (poke 0 #x4015)                     ; Silence all channels
  
positive.code:        (top-ntaddr  (zp #x97))
         (vblank-flag (zp #x96)))         ; Set by NMI handler.
  
    (emit music)
  
    (procedure reset
      (sei)
      (cld)
  
negative.code: (let* ((global (make-instance 'basic-context :address #x8000))
         (*context* global)
         (num-wavy-lines (* 3 26))        ; Must be multiple of 3 !
         (log2-wavy-period 5)
  
         ;; Variables:
         (sprite-table #x0300)
         (table-x      #x0200)
  