[power-gnu-discuss] Support for the MPC5554 (e200z6 core)

[Andrew Dennison]

On Tue, Jun 2, 2009 at 7:25 AM, David Brown <david at westcontrol.com> wrote:
> Hi,
>
> I have a customer who is looking at using a Freescale MPC5554 in an
> application, and is looking for appropriate tools.  I've been having a look
> at the Lite edition of the CodeSourcery PPC gcc toolset. Unfortunately, I've
> run into a big problem.
>
> The MPC5554 uses the e200z6 core, which is fairly similar to the e300c2 core
> supported by the "-mcpu=e300c2" flag.  The problem with both these cores is
> that they support hardware floating point for single precision arithmetic
> using the "SPE" (Signal Processing Extension) instructions, with the
> floating point data held in general purpose registers - they do not support
> the Book E floating point registers and instructions.  My problem is that I
> cannot get gcc to generate spe instructions for hardware floating point
> code.
>
> Does anyone know if current gcc versions support using spe instructions for
> hardware floating point, or if there is likely to be any support soon?  If I
> can't find a way to generate the spe instructions from gcc, I'm going to
> have to recommend my customer buys Code Worrier...

-fshort-double triggers gcc to emit the single precision floating
point instructions.