Hello,

this is a revision of my proposal to use globals for the 8 or 16 CPU
registers on i386 and x86_64.

The changes with my previous patch are:

   - take into account Aurélien's comments
   - get rid of USE_REGS define (thus the old way of accessing x86
     is no more)
   - respect the original order of functions
   - simplify code in some places.

It would probably be good if someone could give this a test for
system mode, as I only tested user mode i386/x86_64 on a
x86_64 host and i386 on i386.


Laurent