(cc'ed to port-sh3@netbsd.org, hope you don't mind)

>We are working on a SH4 port of the SH3 source tree, we've been using the
>source to try to get a 4.4BSD kernel to boot on the dreamcast & the PDA
>units.  I'd like to give you a little status report on what we've seen in
>the portability so far..

	Hi, glad to hear from you,
	Actually there are couple of people working on NetBSD/sh3,
	mainly msaitoh@netbsd.org and tsubai@netbsd.org.  I'm just a
	contact point :-)

>As it is, the sh3 code will boot on the sh4, or at least, theoretically
>should.  We have compared the code using hitachi's hardware manuals, and I
>didn't see any conflicts with the configuration.  
>
>I, however, have not had the chance to boot the code on a SH4 system yet.
>We are currently trying to work on getting the code to boot from the
>system, so we have not booted it as of yet.  (Do you know of any sh4
>emulators that hitachi might have?  We didn't find any to test the source
>on, and I can't really afford the eval-board.)

	I dunno, I know they market eval board but I'm not sure about
	emulations.

	There are differences in MMU, I believe, so there should be some work
	to be done.  Fortunately SH4 code is being worked here as well so
	you will not need much troubles.
	I think the tricky part is bootloader in, eh, sega "dreamcast" console
	or WinCE devices.  Do you have vendor documentation for it?
	NetBSD/hpcmips people (NetBSD on MIPS-based WinCE devices) is booting
	NetBSD kernel from a bootloader program that runs on WinCE, just like
	booting unix kernel from boot.exe on MS-DOS.

>Hope to see you around.  I'll be sure to tell you of any code that would
>be useful in your sh4-support.
>Ja Mata! :-)

	I'll be going to FreeBSDCon (Berkeley CA, next month).  If you happened
	to be there, I can see you there.

itojun