Re: [Xen-devel] [PATCH 08/16] xen: arm: Make register bit definitions unsigned.

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2013-11-20 at 19:29 +0000, Stefano Stabellini wrote:
> On Wed, 20 Nov 2013, Ian Campbell wrote:
> > Otherwise the results of the shifting can be undefined and/or sign extended.
> > 
> > Pointed out in the context of HCR_* by Pranavkumar Sawargaonkar.
> > 
> > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> > Cc: Pranavkumar Sawargaonkar <psawargaonkar@xxxxxxx>
> 
> Do you realize that by using U instead of UL, it would be 4 bytes even
> on ARMv8? Is that expected? If so maybe adding a line to the commit
> message would be good.

Hrm yes. For most of the registers that is expected/desired since the
actual register is 32-bits, but for HCR in particular it should be 32
bits on 32-bit and 64 bits on 64-bits, which might be tricky to arrange
with these macros. I'll see what I can do. We only actually use bits
0..31 since bits 32+33 aren't useful to us (at least not now) so I might
end up fudging it somehow...



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