-m31 | -m64
These options are only available with the ELF object file format, and require that the necessary BFD support has been included (on a 31-bit platform you must add –enable-64-bit-bfd on the call to the configure script to enable 64-bit usage and use s390x as target platform).
-mesa | -mzarch
The 64-bit instructions are only available with the z/Architecture mode. The combination of ‘-m64’ and ‘-mesa’ results in a warning message.
z196. Assembling an instruction that is not supported on the target processor results in an error message. Do not specify