Re: Report on NetBSD-CURRENT and `hpcmips` on MobilePro 780

[Warner Losh <imp%bsdimp.com@localhost>]

On Fri, Dec 22, 2023, 3:55 PM Alexander Bochmann <ab%lists.gxis.de@localhost> wrote:

> ...on 2023-12-21 11:47:28, David Brownlee wrote:
>
>  > It should be possible to build a soft-float userland which avoids FPU
>  > entirely. If the relevant issues go away then that isolates it to an FPU
>  > issue
>
> Oh well... The detail I forgot about since last looking at this
> is that the build configuration in sys/arch/hpcmips/conf/std.hpcmips
> has
>
>  > options         NOFPU                   # No FPU
>  > options         FPEMUL                  # emulate FPU insn
>
> ...since there's no FPU in the vr41xx CPUs.
> (Insert facepalm emoji here.)
>
> From a quick grep at least, no other MIPS sub-architecture seems
> to use that option, so probably no one else would notice if
> something was broken in that code. Then again, that could be
> another ill-advised train of thought.
>

You could do a nice a/b test. Boot a r4000 Malta in qemu.
 Confirm it works.
Add the options to the Malta kernel and try again.

Warner

>