RE: ABI, I don't get it...

[ANDY KENNEDY <ANDY dot KENNEDY at adtran dot com>]

> From: Maciej W. Rozycki [mailto:macro@imgtec.com]
> Subject: Re: ABI, I don't get it...
> 
> On Sun, 14 Aug 2016, Paul_Koning@Dell.com wrote:
> 
> > > with a toolchain that was supposedly 64-bit native, hard-float.  Why
> > > the floating point selection is soft, I cannot say.
> >
> > Perhaps because some other MIPS64 machines don't have float?  The
> > Sibyte series comes to mind.  We use soft-float for that reason, even
> > though XLR and XLP do have it.
> 
>  FYI, the SiByte/Broadcom SB-1 processor cores do have an FPU albeit IIRC
> early (A0?) steppings had fatal errata making the unit less than usable
> (they also had other issues making them usable even less).  This may have
> been the reason you have chosen a software configuration which avoids the
> use of the FPU with these processors.  Later revisions were fine.  I've
> used the FPU with a B2 stepping SB-1 myself with no issues; there was a
> later C0 revision as well.

Not sure what that processor is.  This one is the Broadcom/NetLogic XLP
which have fairly high-end gpu's as the FPU on each core.  Fairly slick
processor and supposedly a powerhouse number cruncher.

I would not think that the NetLogic flagship (the main draw being the FPU)
would have issues like this -- though, who knows!

Thanks for the info!

Andy

> 
>  Ralf (cc-ed) may remember a bit more about the story here.
> 
>  FWIW,
> 
>   Maciej