SuperWord optimization

[James Walsh]

Is there some documentation of hdl used in x86_32.ad?  How would I
describe a XMM register as a whole in that language?  Obviously
MOVAPS, ADDPS, etc and the like will need to reserve a whole XMM
register, not just XMM0a etc.  Looking at the description of the XMM
double register definitions I could probably guess but if there is some
official docs it would be nice to take a look at them.  The quad word
function could probably use a little remider for users to make sure
they index into the array a sufficient amount or there could be
problems.