On Thu, Jan 06, 2011 at 03:54:46PM +0000, Peter Maydell wrote: > On 6 January 2011 15:50, Aurelien Jarno <aurel...@aurel32.net> wrote: > > On Wed, Jan 05, 2011 at 11:15:15AM +0000, Peter Maydell wrote: > > >> Isn't this adding b to the msw of a, rather than the other > >> way round as the comment claims? > > > > I think the comment is actually wrong in both way, as a shift is > > applied, and thus lsw of b is used as the msw in the addition. > > We add the whole of b, not the lsw of b, because it's only > 32 bits to start with (ie "lsw of b" is a longwinded way of > saying "b"). > > > What about "Add a to (b << 32). Mark inputs as dead."? > > To me "Add x to y" means "y = y + x". In this case that would > mean "(b << 32) = (b << 32) + a", which is nonsensical. > "Add (b << 32) to a" or equivalently "add b to the msw of a" > makes more sense to me. >
Ok, will use that in the next version. For the subtraction, how would you say a = (b << 32) - a ? -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel32.net
