Building RTEMS. Targets and overrides...

[Ralf Corsepius]

On Thu, 2005-08-04 at 13:09 +0200, Per Dalgas Jakobsen wrote:
> Hi all,
> 
> I'm trying to build RTEMS-4.6.2 on a Cygwin host for a Pentium target.
> I have successfully made a cross-toolchain for i586-rtems: 
> binutils-2.16.1, newlib (CVS from yesterday) and gcc-3.4.4

Are you sure you did? How did you configure the toolchain?

> Now I got to building RTEMS;
> 
> Unfortunately it seems not so easy to configure RTEMS for an 
> 586-optimized toolchain/compiler.
>
> Any good reasons for that?
Yes, because it doesn't make much sense.

i586 is treated as a cpu variant of the i386 architecture (some call
this the "base architecture"), i.e. as 
"i386-rtems-gcc -mtune=pentium"

> I tried a couple of different things to circumvent the problem, but no 
> success so far (see below).
> 
> Any suggestions?

> Then I tried
> * configure --prefix=/opt/i586-rtems --target=i386-rtems 
> --program-prefix=i586-rtems- --disable-cxx --enable-rtemsbsp=pc586 
> --disable-itron
> 
> configure passes, though a couple of suspicious outputs appears from 
> c/configure:
> "checking host system type... i386-pc-rtems" - Should host be rtems???
Yes.

> "checking for i386-rtems-strip... no" - Strange... I asked to look for
> i586-rtems-<tool>.
No, you used --target=i386-rtems, i.e. you asked it to look
for i386-rtems-<tool>.

> Checking the call to c/configure:
> /home/Per/Tuxway/src/rtems-4.6.2/c/configure'
> '--prefix=/opt/i586-rtems' 
> '--host=i386-rtems' '--build=i686-pc-cygwin' '--target=i386-rtems' 
> '--program-prefix=i586-rtems-' '--disable-cxx'
> '--enable-rtemsbsp=pc586' 
> '--disable-itron' '--with-target-subdir=i386-rtems' 
> '--exec-prefix=/opt/i586-rtems/i386-rtems'  '--cache-file=/dev/null' 
> '--srcdir=/home/Per/Tuxway/src/rtems-4.6.2/c'
> 
> "--host" and "--exec-prefix" is specific. - Should it be that way?
Yes.

> And it does not help to try to override "--exec-prefix"...
Right, this is how it is supposed to work. During cross-compilation, GCC
and GNU conventions mandate certain implications, which result into
overriding --exec-prefix.

Ralf