On 05/19/2010 05:41 AM, Vitus Jensen wrote:
On Wed, 19 May 2010, Gary Thomas wrote:
On 05/19/2010 03:38 AM, Vitus Jensen wrote:
We noticed a strange problem with C++ code casting long long variables
to double, as a lot of qt-embedded code is doing.
=================
double
convert(long long l)
{
return (double)l; // or double(l)
}
int
main(int argc, char * argv[])
{
long long l = 10;
double f;
f = convert(l);
printf("convert: %lld => %f\n", l, f);
return 0;
}
====================
output:
convert: 10 => 0.000000
C++ compiled via powerpc-angstrom-linux-g++ gives the above result.
Compiling the same code as C using powerpc-angstrom-linux-gcc works
fine. But when looking at the assembler code both compiler produce
virtually identical output and both call __floatdidf to do the actual
conversion. Very strange, has anyone ever seen similar effects?
Is this from a recent tree (i.e. post Richard Purdie's restructuring)?
I've seen similar problems with C++ code on Poky which uses the same
changes.
No, I'm building everything from the stable branch. There were some
commits cherry-picked from .dev but those only add Qt 4.5.2.
Poky is ARM only, right? Perhaps it would be helpfull to build a
compiler from .dev and for a widely used powerpc-platform? How does
n1200 sound? It uses the same ppc603e.
Actually, Poky also supports PowerPC now :-)
That said, it may or may not be related. I'll do some investigating.
Thanks for isolating this problem to such a simple example.
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
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