This implements a subset of the AdvSIMD shift operations (namely all the
none saturating or narrowing ones). The actual shift generation code
itself is common for both the scalar and vector cases but wrapped with
either vector element iteration or the fp reg access.
The rounding operations need to take special care to correctly reflect
the result of adding rounding bits on high bits as the intermediates do
not truncate.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
4d1cef840d