There are instructions in 64 bit mode which have been turned into the
REX and VEX prefixes, and which should no longer behave as instructions.
When not in 64 bit mode however, those instructions still need to behave
properly.
We were handling that for the REX prefixes by explicitly checking if the
prefix we found was one of those, and then whether we were in 64 bit
mode or not. We were not handling the VEX prefixes at all, so those were
always acting as prefixes, even when not in 64 bit mode.
This change replaces the REX check and possible VEX check by having two
prefix tables, one for 64 bit mode, and one for otherwise. The REX and
VEX prefixes are simply left out of the non 64b it mode table, making an
explicit check for them unnecessary.
Change-Id: Ia2fc17074015e074d1f156177bd499d67da5411d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55587
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
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