[ydl-gen] String instructions emulation on PPC970MP

[Robert Spykerman]

On Wed, Dec 9, 2009 at 12:08 AM, Patrice B <pbfwdlist at gmail.com> wrote:
> Hello,
>
>  I'm using a Power Station as a build machine to generate code for
> amcc440 cpu using gcc 4.4 with option -mcpu=440fp. Since this release
> of gcc, I notice that code is generated with string instructions which
> are not supported by Power Station cpu, and then, it makes build
> failed if a newly built binary needs to be run for a next build step.
> Is there a way to emulate those instructions on a Power Station (which
> currently runs YDL 6.0).

Hmm.. one other solution I thought of is to try this on your 970 gcc.

-mcpu=440fp         and     -mno-dlmzb

I had to do a bit of googling, these are the instructions you mean?
Because I think the 'regular string' multiload instructions (ie load
contiguous registers from a contiguous block of mem) are common to
most powerpcs now, even the 440 I believe. The 970/cell certainly has
it.

The other thing is to try is possibly

-mcpu=common     and     -mtune=440fp

That way /maybe/ you get just the 'common' set of instructions used
and the scheduling tuned for a 440fp.

Worth a try I reckon.

But of course, other important issues could be the call convention /
ABI / endedness etc. That I do not know about on your target. Maybe a
cross compiler is the better solution.

>  Best regards
>
>        Patrice

Robert Spykerman

-- 
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