I recommend to take a look to radare2 [1] - reverse engineering framework, which also has an ability to perform assembling for some architectures (and supported

I recommend to take a look to radare2 [1] - reverse engineering framework, which also has an ability to perform assembling for some architectures (and supported architectures and file formats count [2] is way beyond mentioned on METASM's site). [1] http://rada.re http://rada.re [2] https://github.com/radare/radare2 https://github.com/radare/radare2