H. Peter Anvin wrote:
 >>> Ummm...last I knew, fxrstor is *expensive*.  The fninit/xor regs
 >>> setup is  likely *very* much faster.  Someone should check this
 >>> before we sacrifice  100 cycles needlessly or something.
 >>
 >> most probably yes, fxrestor needs to read ram, pxor also takes
 >> some icache and bytecode ram but it sounds like it will be faster.
 >>
 >> Maybe we could also interleave the pxor with the xorps, since they
 >> uses different parts of the cpu, Honza?
 >>
 >
 >
 > You almost certainly should.  The reason I suggested FXRSTOR is that
 > it would initialize the entire FPU, including any state that future
 > processors may add, thus reducing the likelihood of any funnies in
 > the future.

Here's a patch to do just that.  It initializes the saved state in the
task struct and falls through to restore_fpu().

-- 

						Brian Gerst