Re: rex.W prefix in jumps on x86_64

[Marc Nieper-Wißkirchen]

May I check with you whether this issue has reached you, Paulo?

Thanks,

Marc

Am Sa., 25. Apr. 2020 um 21:02 Uhr schrieb Marc Nieper-Wißkirchen
<marc.nieper+gnu@gmail.com>:
>
> Hi,
>
> I am currently using the development version of GNU lightning. When I
> look at the disassembly, I see things like
>
> rex.W jmpq *%rax
>
> when an instruction like `jmpr R0' is jitted. I am wondering about the
> REX prefix, which doesn't seem to be necessary. In 64 bit-mode, where
> the operand size is fixed for jumps and calls.
>
> Thanks!
>
> Marc