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Date: Tue, 9 Oct 2018 14:55:34 +0100
From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= <berrange@redhat.com>
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	<w51sh1f8bwq.fsf@maestria.local.igalia.com>
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Subject: Re: [Qemu-devel] [PATCH 5/6] crypto: convert xts_mult_x to use
 xts_uint128 type
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To: Alberto Garcia <berto@igalia.com>
Cc: qemu-devel@nongnu.org

On Tue, Oct 09, 2018 at 03:52:53PM +0200, Alberto Garcia wrote:
> On Tue 09 Oct 2018 02:55:40 PM CEST, Daniel P. Berrang=C3=A9 wrote:
> > -static void xts_mult_x(uint8_t *I)
> > +static void xts_mult_x(xts_uint128 *I)
> >  {
> > -    int x;
> > -    uint8_t t, tt;
> > +    uint64_t tt;
> > =20
> > -    for (x =3D t =3D 0; x < 16; x++) {
> > -        tt =3D I[x] >> 7;
> > -        I[x] =3D ((I[x] << 1) | t) & 0xFF;
> > -        t =3D tt;
> > -    }
> > -    if (tt) {
> > -        I[0] ^=3D 0x87;
> > +    tt =3D I->a >> 63;
> > +    I->a =3D I->a << 1;
> > +
> > +    if (I->b >> 63) {
> > +        I->a ^=3D 0x87;
> >      }
> > +    I->b =3D (I->b << 1) | tt;
> >  }
>=20
> Does this work fine in big-endian CPUs?

Hmm, that's a good question. I'd expect tests/test-crypto-xts to crash
and burn if it doesn't, so guess I'll need to find somewhere to validate
that.

Regards,
Daniel
--=20
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