Re: [Qemu-devel] [PATCH] SH: Add prefi, icbi, synco

[Paul Mundt]

On Fri, Oct 17, 2008 at 08:56:52PM +0100, Paul Brook wrote:
> On Friday 17 October 2008, Vladimir Prus wrote:
> > This patch makes qemu recognize (and ignore), three instructions from SH4A.
> 
> Shouldn't these generate an illegal instruction exception on SH4 cpus?
> 
Note that all of these are SH-5 instructions, which gradually found their
way in to the SH-4A ISA. There are also other SH-5 instructions that have
found their way in to the SH-2A ISA which are not as of yet reflected in
SH-4A. The dependency tracking gets to be pretty ugly, as is evident in
binutils. In order to get this right, it would be necessary to throw ISA
versioning in to the CPU definition and test to figure out what to
support, as per the table in binutils. While this would be a good idea in
general, it is something that should be done as a larger follow-up to
these patches.