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Opcodes
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.. note:: Opcodes are used in **.eff** (effect) files - and in embedded versions in **.itm** (item) and **.spl** (spell) files - and provide additional features and functionality in all the Infinity Engine games. The ``effect type`` field of the `EFF V1.0 <https://gibberlings3.github.io/iesdp/file_formats/ie_formats/eff_v1.htm#effv1_Header>`_ files and the ``Opcode number`` field of the `EFF v2.0 <https://gibberlings3.github.io/iesdp/file_formats/ie_formats/eff_v2.htm>`_ files indicates the opcode in use for a particular **.eff** file. Modifying existing **.eff** files to change opcodes used, or creating new effects is usually done with modding tools such as `WeiDU <http://www.weidu.org>`_ or `NearInfinity <https://github.com/Argent77/NearInfinity>`_. For details on the different opcodes (effects) available in the Infinity Engine games, see the `Infinity Engine Structures Description Project <https://gibberlings3.github.io/iesdp/index.htm>`_

EEex expands on the capability of some existing opcodes, and adds new opcodes for mod makers to make use of.

.. toctree::
   :maxdepth: 2

   Changed/index
   New/index