structures.
Add more interface functions to isolate structure internals and make it
easier to add warnings (such as for multiple overrides/prefixes).
svn path=/trunk/yasm/; revision=43
instruction (which takes two immediate values).
To facilitate this change, changed meaning of "len" in bytecode structure
to be only the length of the offset (from being 1+length, the 1 being for the
Mod/RM byte), and added a need_modrm flag similar to the need_sib flag in
functionality.
svn path=/trunk/yasm/; revision=22