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9.38.1 Options

The following table lists all available s390 specific options:

-m31 | -m64
Select 31- or 64-bit ABI implying a word size of 32- or 64-bit.

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
Select the architecture mode, either the Enterprise System Architecture (esa) mode or the z/Architecture mode (zarch).

The 64-bit instructions are only available with the z/Architecture mode. The combination of `-m64' and `-mesa' results in a warning message.


-march=CPU
This option specifies the target processor. The following processor names are recognized: g5, g6, z900, z990, z9-109, z9-ec, z10 and z196. Assembling an instruction that is not supported on the target processor results in an error message. Do not specify g5 or g6 with `-mzarch'.


-mregnames
Allow symbolic names for registers.


-mno-regnames
Do not allow symbolic names for registers.


-mwarn-areg-zero
Warn whenever the operand for a base or index register has been specified but evaluates to zero. This can indicate the misuse of general purpose register 0 as an address register.