ARMv8.2 16-bit versions have not yet been implemented, but a placeholders were created for them. Refactor the nearby decoding tree to closely match the ARM spec A32 decode table. That piece of the tree can also be called from thumb which decodes it in the same way, although the thumb decode table has a different terminology The old code didn't match neither A32 or T32 terminologies, so it is better to at least match one of them to help verify correctness. Change-Id: Iabbbca2932557cf6c98ce36690c385c3ddf39ed8 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18690 Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>