Subject: Re: Split or don't split arm32?
To: None <tv@wasabisystems.com,tech-ports@netbsd.org,port-arm32@netbsd.org>
From: Ben Harris <bjh21@cam.ac.uk>
List: port-arm32
Date: 12/22/2000 21:35:21
In article <Pine.WNT.4.30.0012221222280.-3732049-100000@todd> you write:
>On Thu, 21 Dec 2000, Ignatios Souvatzis wrote:
>
>: * sharing more source code between arm26 and arm32 seems good to me.
>
>Whatever can be shared is useful, although sharing $MACHINE_ARCH doesn't
>seem completely correct.  Forcing all code to an arm26 memory model is
>somewhat restrictive....

I think you misunderstand.  Shared-mode code would be almost identical to
current arm32 code (differences being that it would have to detect the
processor mode when extracting a return address from a stack frame, and that
the text segment would start at 0x8000).  Running on an arm26 system,
programs would indeed be restricted to 24Mb of virtual memory.  Running on
an arm32 system, though, no such limits would apply.

Obviously, 24Mb of VM will be too little for some programs, but that will
prevent them running on arm26 however they're compiled.  They'll still work
on arm32.

-- 
Ben Harris                                                   <bjh21@netbsd.org>
Portmaster, NetBSD/arm26               <URL:http://www.netbsd.org/Ports/arm26/>