Re: Softfloat on i386

[Alexander Schreiber <als%thangorodrim.ch@localhost>]

On Wed, Dec 31, 2025 at 11:07:20PM +0000, David Holland wrote:
> On Thu, Jan 01, 2026 at 09:30:54AM +1300, Lloyd Parkes wrote:
>  > > In PR 59871, the submitter is asking for all Go on i386 to be switched
>  > > to softfloat, so that the resulting binaries run in a 486.
>  > > 
>  > > Is that a reasonable request? Are pkgsrc binary packages supposed to
>  > > run on 486 processors?
>  > > 
>  > > Or should it be an option?
>  > > 
>  > An actual Intel 486 supports hardfloat, although the built in FPU might not
>  > be feature rich enough for some modern compilers (speculation). The Intel
>  > 486SX is a specially cut down 486 with no hardfloat and I've seen that
>  > implemented by CPU clone makers.
>  > 
>  > I wouldn't object to softfloat being a pkgsrc option for 486SX users.
> 
> The problem is that go is a compiler and it apparently only supports
> codegen for either (a) sse2 and newer or (b) softfloat. This means
> there's a range of non-486SX (and non-486) machines where the only
> working option is softfloat.
> 
> Given the performance cost of softfloat and that we're talking about
> very old machines at this point, i don't think it should be the
> default for "i386" (as in 32-bit x86), but it should be an option and
> somewhere in the setup docs we should tell people to set it if they're
> using such hardware. (Also it might be worth making go builds fail if
> it's not set when on such a machine.)

Having softfloat as an option sounds like a good solution here.
 
> This does to some extent raise the question of what the intended
> purpose of the 32-bit x86 binary builds is these days...

There are still people running NetBSD on i386 class machines, e.g.
the PCEngines Alix (AMD Geode LX800 - essentially Pentium class,
with FPU, MMX, 3DNow! but of course not SSE2) which usually serve
as small routers (for moderate speed networks, the NICs are 100 MBit/s).

I currently have one of those left in service, running NetBSD 10.1 i386.

Kind regards,
           Alex.
-- 
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 looks like work."                                      -- Thomas A. Edison