Q about REGNO_OK_FOR_BASE_P et al

[Robert Baruch <autophile at gmail dot com>]

Hi all,

I'm trying to add a new RISC processor to gcc. I've read through the
GCC Internals manual and "Porting GCC for Dummies". I'm a bit fuzzy on
REGNO_OK_FOR_BASE_P (and its related macros).

The processor I'm working with doesn't have a base-with-displacement
or base-with-index addressing mode. It doesn't have specialized base
or index registers. All of its general purpose registers could be used
in such a calculation, though. So does that mean that all of the
general purpose registers should be ok for base and index, or that
none should be used?

Also, the internals manual states that "[The base register] may be
either a suitable hard register or a pseudo register that has been
allocated such a hard register." Does that mean that a pseudo register
that has NOT been allocated any hard register should always be
considered unsuitable?

Thanks for any help you can give me in porting my processor!

--Rob