> Both asm.h and regdef.h are userland visible headers, and we should
> not remove or change the API without strong reason, IMHO.
>
>> Perhaps Tohru / Castor can comment on this?
>
> Why are these changed ?

Because there was no need of regdef.h in practice for long time.

Seasoned real programmers who are familiar with and reponsible for
well maintained programs useful with NetBSD/mips *did* (*should*) know
that there was no need to use #include <mips/regdef.h> in any places
as far as #include <mips/asm.h> is used to structure assembler coding
style in shape.  After all, current mips/asm.h is less annoying for
people who do ever have experience of writing assembler programs for
commercial MIPS boxes and are concerned with program portability and
reusablity in mind, than it's used to be. 

I'm going to restore regdef.h, however, because;
        [1] to save careless practices
        [2] regdef.h has been existed in MIPS boxes since the age of
        MIPS Co. ucode-based compiler, and still exists even in MIPSpro
        7.0 with glorious extensions.

Tohru Nishimura
Information Technology Centre
Nara Institute of Science and Technology