powerpc64/GENERIC64: a mtmsrd without a "context synchronizing instruction" (immediately?) following...

[Nathan Whitehorn]

On 09/23/14 18:25, Mark Millard wrote:
> Nathan Whitehorn wrote of the use of the document that I was referencing:
>
>> I think you are looking at very old documentation. The 32-bit mtmsr is
>> implemented on all POWER ISA compliant CPUs (see e.g. page 886 of the
>> 2.07 document).
>> -Nathan
>
> I think we may be using different documents rather than different 
> versions of the same document. I may need to find what Nathan is using 
> and its time frame (PowerPC Architecture 2.07?). But he may want to 
> check what I've been referencing. So...
>
> pem_64bit_v3.0.2005jul15.pdf is Version 3.0 and directly from the IBM 
> site and has 657 pages...
>
> https://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/F7E732FF811F783187256FDD004D3797
>
> It is the current document of its type as far as I can tell. The title is:
>>
>> PowerPC® Microprocessor Family:
>>
>> The Programming Environments Manual for 64-bit Microprocessors
>>
>> Version 3.0
>>
>> July 15, 2005.
>

Right, this is massively obsolete. Apparently they were planning to 
deprecate mtmsr and changed their minds. You want the current one from 
https://www.power.org/documentation/power-isa-version-2-07/.

> It is described on its web page as:
>
>> This manual is to help programmers provide software that is 
>> compatible across the family of PowerPC processors. This book 
>> provides a general description of features common to PPC processors 
>> and indicates those features that are optional or that may be 
>> implemented differently in the design of each processor. This book is 
>> for only 64-bit processors.
>
> It is different from other architecture documents in that it also 
> documents the Operating Environment Architecture (supervisor 
> level/privileged-state resources for operating systems), not just the 
> UISA and VEA. The document warns that while the UISA is always adhered 
> to there can be VEA and OEA variations that the document does not 
> cover. But it also says that the "general-purpose" PowerPC 
> microprocessors comply with the document. In its own words...
>

Right, this is the same with the current version of ISA. Book-3S 
describes what was called the OEA at one point. In any event, your 
machine (a PowerPC 970) certainly supports the instruction.
-Nathan