commit 87eb9a3a640875d176bec9dfb130450d23d8e8b8
author Gabe Black <gabeblack@google.com> Wed Dec 20 00:02:47 2017 -0800
committer Gabe Black <gabeblack@google.com> Sat Dec 23 03:36:45 2017 +0000
tree 305da38c7ea611b9404dcf2d8a79e74cac8bef73
parent b7618c69a511e3fde5cdb674a91e5683f92e770f

riscv,x86: Stop using the arch Nop machine instruction unnecessarily.

That particular ExtMachInst is a convenient placeholder, but a value
of 0 in RISCV or a static uninitialized ExtMachInst (which will
therefore be all zeroes) on x86 works just as well, and removes the
need for an ISA specific constant.

Also, the idea of a universal Nop doesn't always make sense since it
could be that what, exactly, doesn't do anything depends on context
which would be lost on a constant value of an ExtMachInst. For
instance, the value of an ExtMachInst that makes sense might depend on
what mode the CPU was in, etc.

Change-Id: I1f1a43a5c607a667e11b79bcf6e059e4f7141b3f
Reviewed-on: https://gem5-review.googlesource.com/6825
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
Maintainer: Gabe Black <gabeblack@google.com>