Feeling somehow guilty about the issue is left uncorrected long time,

> The fact that simple userland programs like regress/lib/libc/ieeefp/except
> crashed my DECstation made me nervous, so I've looked into the issue and
> found 2 serious problems: incomplete siginfo adoption and lacking FPU status
> clearing.

The software FPA emulation code is another major caveat in NetBSD/mips
implementation.  As you already observed, it's now tangled pieces of
obscure code segments which have been accumulated without sensible soul
for long time.  As far as I know, none has been brave enough to {fix|make}
it straight out since the initial import from Sprite/Mach/4BSD-what-so-ever
of real R2000 age.  It's necessary to be replaced with new FP insn and
64bit-register aware implementation written in real-C.

Toru Nishimura/ALKYL Technology