Help XAS...

Hi all !!!! * * * * * * * * * * * People who have a description of XAS? Answer me, otherwise there is an assembler, but it’s a help no :( . The assembler is like that without a glass can’t figure it out :).You need a complete help, so I don't know if there is an automatic one loading blocks during assembly (if the source text is large) or not. So reviews are expected ;) Then another converter GENS -> XAS requires - Thank you, otherwise too many texts will be lost! :( That's it! Answer in echo or soap.