MVME5500 broken with gcc-4.0.2
dufault at hda.com
Mon Oct 31 23:36:19 UTC 2005
On Oct 31, 2005, at 6:05 PM, Till Straumann wrote:
> rtems/gcc (implicitely) uses -maltivec on all 74xx CPUS and
> the MVME5500 calls for -mcpu=7450.
> Unfortunately, with -maltivec, gcc uses vector registers for
> some optimizations.
> --> until proper altivec support is implemented in RTEMS random
> *data corruption* must be expected.
> make/custom/mvme5500: use -mcpu=750
> -- Till
I've been using the mvme5500 24/7 using an earlier rev of gcc 4.0 in
a heavily floating point control application, with optimization on,
with a similar gcc configuration. I don't explicitly use the
altivec. I assume you're saying that gcc is using the vector
registers for data movement but RTEMS isn't saving / restoring them
and that's where the problem should come in, but I'm not noticing any
problems. I've got lots of multi-axis floating point control going
on and a heavy network load. Did anything change in newer 4.0.x
releases? I've built everything with 4.0.2 but haven't run things yet.
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