What tools are available to edit/create AVM2 bytecode?

Question

I'd like to generate some bytecode for the Flash 10 AVM2 directly, i.e. without AS3. An assembler that produced a SWF file would be ideal.

Does this exist? If not, what's the easiest way to get from assembler → abc → SWF?

Answer 1

It looks like As3c is what I'm looking for:

As3c is a bytecode compiler for the AVM2 written in C#.

Answer 2

Not sure if that's what you want but Haxe is opensource. Haxe has also a library that can produce bytecode from Haxe code.