>Someday we'd have to clarify things between locore.h, machdep.h and
>promvar.h. 

When I created locore.h, it was to hold the prototyped declarations of
assembly-coded, mips-specific functions in locore.S and the mips
arch-level specific files.  the mips version is intended to be used on
all mips ports, with any port-specficid declarations in the
port-specific locore.h.

IMHO, promvar.h should hold declarations for pmax prom callbacks and
associated foo. I dont recall what machdep.h is supposed to hold.

I once had notes for what all the (then-defined) per-port kernel
headers were, and what they should declare, but they're hopelessly out
of date.