prettyInstruction _ a (IfZero op r off) =
  mkInsn ("if-" <> ifOpStr op <> "z")
         [ iregStr8 r, word16HexFixed (fromIntegral (a + fromIntegral off)) ]
  <> offComm off
prettyInstruction _ a (IfZero op r off) =
  mkInsn ("if-" <> ifOpStr op <> "z")
         [ iregStr8 r, word16HexFixed (fromIntegral (a + fromIntegral off)) ]
  <> offComm off
prettyInstruction _ a (IfZero op r off) =
  mkInsn ("if-" <> ifOpStr op <> "z")
         [ iregStr8 r, word16HexFixed (fromIntegral (a + fromIntegral off)) ]
  <> offComm off