This includes shifts by immediate, which use bits 3-5 of the ModRM byte
as an opcode extension. With the exception of 128-bit shifts, they are
implemented using gvec.
This also covers VZEROALL and VZEROUPPER, which use the same opcode
as EMMS. If we were wanting to optimize out gen_clear_ymmh then this
would be one of the starting points. The implementation of the VZEROALL
and VZEROUPPER helpers is by Paul Brook.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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