On Sat, Dec 21, 2013 at 03:08:21PM +0100, Paolo Bonzini wrote:
> Il 21/12/2013 00:00, Richard Henderson ha scritto:
> > + if (real_bswap && have_movbe) {
> > + tcg_out_modrm_offset(s, OPC_MOVBE_GyMy + P_DATA16 + seg,
> > + datalo, base, ofs);
> > + tcg_out_ext16u(s, datalo, datalo);
>
> Do partial register stalls still exist on Atom and Haswell? I don't
> remember exactly what you had to do to prevent them, but IIRC you first
> moved zero to the register and then overwrote the the low 16 bits.
Note that for unsigned 16-bit load you can do either movzw + bswap or
movbe + movzw.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurel...@aurel32.net http://www.aurel32.net
