[patches] Re: x86_64 gas documentation

[Jan Hubicka]

> +These options are only available with the ELF object file format, and
> +require that the necessary BFD support has been included (on a 32-bit
> +platform you have to add --enable-64-bit-bfd to configure enable 64-bit
> +usage and use x86-64 as target platform).
> +@end table
In order to make --64 option work, you need to compile in an 64bit format
support (elf64-x86-64 is the only choice at the moment).
Similary --32 requires some of the 32bit formats.

The --enable-64-bit-bfd is implicit then.

Note that your note about addressing is wrong - even when address is 0,
it is encoded as 32bit immediate and resulting instruction is one
byte shorter than when expressed by RIP relative way.

Also I've missed the 64bit absolute addressing mode present in mov instruction
- I will add this maybe by separate patch OK?

Honza