anchor.diff:  
       ;; Wavy effect
       (flet ((kernel ()
  -             (poke #b00011110 +ppu-cr2+)
  +             (poke #b11111110 +ppu-cr2+)
                (clc)
                (lda wt-get)               ; Get wave offset
                (adc scroll-x)             ; Add to BG scroll position
  
positive.code:     (txs)
  
      ;; Initialize music player.
      ;;(lda (imm 0))                       ; song 0
      ;;(ldx (imm 0))                       ; NTSC
      ;;(jsr music-init)
  
      ;; Init sound hardware
      (poke 0 #x4015)                     ; Silence all channels
  
negative.code:        (top-ntaddr  (zp #x97))
         (vblank-flag (zp #x96)))         ; Set by NMI handler.
  
    (procedure reset
      (sei)
      (cld)
  