>I defined a type mips_fpreg_t in types.h so people could choose the size
>of registers to save, but forgot to implement this in the usual places.
>
>I thought it would be better to leave those developing embedded systems
>with the choice of sizes since they might be more memory constrained.

That's you, right?  If you do that, fine, but I guess you'd need your
own emul and ident tag, or something.

>If we did this, would it be unreasonable to swap the positions of
>sc_fpc_eir and sc_fpregs in the sigcontext struture so alignments
>are preserved?

Yes, sounds like a good idea, except that it breaks binary
compatiblity between kernel/userland `before' the change and `after'
the change: old-kernel + new-userland or, new-kernel + old-userland
curdle theFPU state -- even for the 32-bit world. `Yuck'.  (That's
practical for you, but not really for NetBSD, not without a
major-version bump).

Is the fpu CSR 32 or 64 bits wide in 64-bit FPU mode?
Could we fix alignment by moving the CSR?