Re: Minimal machine description file

[Michael Meissner <gcc-mail at the-meissners dot org>]

On Fri, May 02, 2003 at 11:33:27AM +0100, Roger.Gough wrote:
> Hi all,
> 
> I have managed to modify my configure scripts so that gcc recognizes my new
> target (called "npe"). Thanks to Alex Courbot for his help here.
> My next challenge is to write my machine description files. Scrolling
> through the gcc archives, I realised that many people have been looking for
> the minimal characteristics to achieve a functioning port of gcc. I was
> wondering if anybody had achieved this and if so where would I find it
> documented?
> If not, would anybody recommend some target files for a similar architecture
> to mine. y intention would then be to modify these files to accomodate my
> architecture.  The architecture I am porting to is a 32-bit RISC
> microcontroller core with:
> -load/store instruction set
> -Harvard Architecture
> -4/5 stage pipeline
> -16 hardware contexts
> Any help or advice would be greatly appreciated.
> Kind Regards.
> Roger.

When I was working at Cygnus and then later Red Hat, I had made a generic port
that was useful in starting new ports, but it was never released or tested.
Which meant every time the base code at the FSF changed, the port became
somewhat less useful and more buggy.

Your above machine sounds fairly simple.  Just about any RISC platform will do,
but many of the popular ones can be overloaded with lots of stuff from
supporting multiple calling sequences for different subtargets (ie, the powerpc
and mips ports).  For the basic port, maybe something simple like the M32R
might be best.

-- 
Michael Meissner
email: gcc-mail@the-meissners.org
http://www.the-meissners.org