On Wed, 19 May 2010, 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.
Unfortunately .dev switched to gcc-4.3.3 in the meantime which fails for
ppc603e platforms because of undefined references to __nldbl_fprintf and
__nldbl_sprintf during compile.
Platform tqm8540 (ppce500, just to try some other ppc cpu) fails in
gcc-4.3.3 compile, too. Possible related to this:
endian.h:34:4: warning: #warning Cannot determine current byte order,
assuming big-endian.
So currently .dev should be unbuildable for ppc users? Without selecting
a non-default compiler that is.
Vitus
--
Vitus Jensen, Hannover, Germany, Universe (current)
pgp public key available from keyservers
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