[RFC][PATCH 0/2] Make sparcv8 work again on cas enabled hardware

[Richard Henderson]

On 11/03/2016 11:22 AM, David Miller wrote:
> From: Torvald Riegel <triegel@redhat.com>
> Date: Thu, 03 Nov 2016 16:39:21 +0100
>
>> Is there any difference between the additional CAS on a v8 and the CAS
>> on a v9?  If there should be none (eg, same instruciton encoding etc.),
>> we wouldn't need a runtime check for this, would we?
>
> A quick look at binutils shows that the encoding appears to be the same.

Yes and no.  The instruction format is the same, but the ASI used is different.

The CAS for leon userspace uses ASI_USERDATA (0x0A), not the v9 ASI_P (0x80). 
It's a really annoying difference that I wish the cpu designers hadn't made.


r~