flash language_api_dynamic_translation

In order to optimise performance, the virtual machine 2 (AVM2) of Flash player 9 integrates an innovative compilation mechanism of the code on the fly. As much as this term may seem astonishing, this principal is called dynamic translation. In previous versions of Flash player the swf code was directly rewritten by the virtual machine in order to obtain better execution performances of the execution code.

In previous versions of Flash player, the code in the swf was directly rewritten by the virtual machine in machine language without any optimisation linked to the platform used.

In ActionScript 3 the virtual machine rewrites the binary code (ActionScript byte code) in machine language with the help of a compiler called ‘just-in-time compiler’. This allows you to only compile the used code in an optimised manner depending on the platform used.

The virtual machine can therefore optimise instructions for a specific processor while taking different platform constraints into consideration. For more information linked to compilation on execution: http://en.wikipedia.org/wiki/Just-in-time_compilation