Subject: Re: needs MI wdc changes to support macppc's wdc
To: Izumi Tsutsui <>
From: Allen Briggs <>
List: tech-kern
Date: 10/25/1998 09:24:18
> I'd like to use the MI wdc.c for it, but offsets of registers
> defined in wdcreg.h don't match macppc's wdc registers.
> The offsets of macppc's wdc registers are aligned every 16 bytes.
> [...]
> On the other hand, atari's wdc has also non-contiguous offsets
> but atari's mb_bus_space_*() functions handle it as contiguous.
> I heard that mac68k's wdc had non-contiguous offsets, too.

The mac68k wdc has non-contiguous offsets, too.  I think it's also every
16 bytes.  I think that the cleanest solution is to make the bus_space*()
functions handle the register addressing, but I don't know if anyone has
measured any performance penalties that you might incur from doing so
(for the regions that don't need the offset modified).


                    Allen Briggs -
       Try free *nix:,,,