Serious bug in 4.9.0 (FP ctxt corruption on some ppc-e500 BSPs except mvme3100)

[Till Straumann]

Ralf Corsepius wrote:
> On Fri, 2008-09-26 at 19:54 -0700, Till Straumann wrote:
>
>   
>> In the future -- once we have proper context-switching in place -- the
>> new multilib variant may indeed be useful but ATM it must not be used!
>>     
> In this case, the part in rtems which contains the responsible task
> switch magic should refuse to compile.
>   
Impossible.

a) This is a new multilib variant; the task-switching code has
    no knowledge of it (yet).

b) There is no preprocessor-symbol that can be tested to find
     out if -mfloat-gprs is in effect (and no, we don't want to go
    back and base the decision on the CPU flavor).

    IMHO rather than setting rs6000_float_gprs=1 under the hood
    it would be better to explicitly use -mfloat-gprs=single and
    define a CPP symbol reflecting the setting of -mfloat-gprs

    This way, we could find out during the build and produce
    an appropriate multilib variant (once switching the upper
    32-bit of the GPRs is implemented.

For now, however, -msoft-float must be added to the cflags
for all affected BSPs.

T.
> Former RTEMS versions did so.
>
>
>