AmosPro is a BASIC programming language with extensions that add commands to the language. It includes a rich set of multimedia instructions for the Amiga Enhanced Chipset.
If you want AGA support, you should use AmiBlitz instead (formerly known as Blitz Basic). It is not as easy to use as AmosPro but it is MUCH more powerful and system friendly at this point.
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The download link to AmiBlitz is at
http://amiblitz3.amiforce.de/. There is also a forum for and even though it is mostly German several of the AmiBlitz developers speak English.