Re: [PATCH 2/7] target/ppc: Add support for prefixed load/store instructions

[Gustavo Romero]

Hi David,

On 10/8/20 10:45 PM, Paul A. Clarke wrote:
> On Fri, Oct 09, 2020 at 11:50:10AM +1100, David Gibson wrote:
> > On Mon, Oct 05, 2020 at 01:03:14AM -0300, Gustavo Romero wrote:
> > > From: Michael Roth <mdroth@linux.vnet.ibm.com>
> > >
> > > This commit adds support for the following prefixed load and store
> > > instructions for GPRs:
> > >
> > >    plbz, plh{a,z}, plw{a,z}, pld, plq
> > >    pstb, psth, pstw, pstd, pstq
> > >    paddi
> >
> > Are there architecture docs publically available yet which describe
> > these instructions?
>
> Are you looking for the ISA?  The "Power ISA Version 3.1" can be found
> at https://www-355.ibm.com/systems/power/openpower/, under "Public
> Documents" (POWER10 ISA), or directly at this horrible link:
>
> https://ibm.box.com/s/hhjfw0x0lrbtyzmiaffnbxh2fuo0fog0

As Paul pointed out (thanks Paul!) - and provided links for, you can check
the added instructions by that patch series in Power ISA v3.1. I think the
first interesting bits in ISA v3.1 for that series would be the following:

1.6 Instruction Formats, p. 11.

For those not aware, there is a bold black marker at left of every new text
in comparison with the immediately previous ISA version (v3.0), which works
like a "diff" for the ISA text, so the marks can be helpful for locating a
new text regarding prefixed instructions (prefixed instructions were
introduced in v3.1) in sections like 1.6, which also contains old text.

Secondly:

1.6.3  Instruction Prefix Formats, p. 22,

which will describe most of what is addressed in 1/7 for adding the
prefixed insns infrastructure.

Then one can find more information about the new added instructions, like
plbz, VSX-related, and FP-related ones in:

3.3.2  Fixed-Point Load Instructions, p. 51
4.6.2  Floating-Point Load Instructions, p. 149

There is also new text scattered all over Chapter 7 Interrupts, p. 1247,
mostly because there are new SRR bits to inform if an exception or interrupt
was caused by a prefixed instruction. In that case the thick bold marks
(marking new text) might help to find the new parts.

I'll add these references to v2.

HTH.


Thanks,
Gustavo