Re: New target for Coldfire v4e?

[Peter Barada <peter at the-baradas dot com>]

>>   I want to submit the changes for ColdFire v4e.
>
>That's very good news indeed!
>
>GCC's main development branch is currently in stage 3; that
>means only regression fixes are being accepted at the moment.
>
>To save time, you may start submitting patches now, but
>we'll have to wait until the development of GCC 4.1 resumes
>in order to commit them.

Before you submit any patches, a very strong suggestion is to check
out a current version of gcc(or snag a current snapshot), put it into
a local CVS repository and make your changes to that to support
ColdFire v4e, that way you know:

1) That the changes you want to make work against the current compiler
2) Exactly what parts need to change.

This approach will naturally lead you to breaking up the diffs to your
CVS repository into bite-sized pieces, especially if you break up the
checkins to your CVS tree.

>> I had to modify t-linux for multi-lib part. Will these
>> changes be acceptable or do i have to create a new target for ex.
>> coldfire-linux?
>
>That depends on how your changes affect other m68k-linux
>users.  If you removed 680x0 processors, you certaily need
>to create a different target triplet.
>
>I'm sure we *can* keep v4e along with other m68k targets.
>Most of your changes are probably processor-specific (new
>instructions, etc.).  These can easily be shared.
>
>The other changes to the m68k-linux target are probably
>meant to generate multilibbed libraries for the new m68k
>variant, these can be shared too.
>
>Does m68k-linux have some special requirements such
>as tweaks to the ELF format for shared-library support?

Since PIC support for m68k uses a mode-6 variant to acheive 32-bit
register offset addressing, and ColdFire doesn't support that
addressing mode, then changes needed to be made for PIC addressing
support.

>The uClinux target has *many* such tricks and thus it's
>been made a separate target.

I'd suggest a new target (--target=coldfire-linux) just to seperate
the changes and make it much easier to make sure that you don't break
m68k-linux.  This will dovetail with the add-on in glibc to support
ColdFire as well... 

-- 
Peter Barada
peter@the-baradas.com