target/arm/translate-a64: Don't underdecode SIMD ld/st single
In the AdvSIMD load/store single structure encodings, the
non-post-indexed case should have zeroes in [20:16] (which is the
Rm field for the post-indexed case). Bit 31 must also be zero
(a check we got right in ldst_multiple but not here). Correctly
UNDEF these unallocated encodings.
Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Message-id:
20190125182626.9221-5-peter.maydell@linaro.org