Rewrite the vector shift helpers in preperation for AVX support (3 operand
form and 256 bit vectors).
For now keep the existing two operand interface.
No functional changes to existing helpers.
Signed-off-by: Paul Brook <paul@nowt.org>
Message-Id: <20220424220204.2493824-11-paul@nowt.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>