I've been looking into this problem, I don't seem to be able to track it
down. With the addition of gcc-4.4.0 to the cegcc toolset, the ARM
float/double arithmetic appears to be broken.
Environment is cross-development for execution on Windows CE platforms,
for ARM processors.
I'm looking for pointers to understanding this. Fixes would be welcome
too but that might be a bit much to ask ;-)
Consider this test program. I'm not sure how sensible it is, but
it shows at least two current problems.
#include <stdio.h>
#include <windows.h>
main(int argc, char *argv[])
{
double d = 12.0;
double dd = d * 3.0;
double ddd = 36.0;
float fd = 36.0;
printf("Foo %d %f %d\n", 34, d, 67);
printf(" 12 * 3 -> %f\n", dd);
printf(" 36 -> %f\n", fd);
printf(" 36 d -> %f\n", ddd);
exit (0);
}
Its output, with the gcc 4.4 build chain on my disk, is :
pavilion: {233} arm-mingw32ce-gcc -o float-n2.exe float.c
-Wstrict-aliasing=2
pavilion: {234} rcp float-n2.exe ipaq:/temp
pavilion: {235} rsh ipaq /temp/float-n2.exe
Foo 34 12.000000 67
12 * 3 -> 0.000000
36 -> 0.000000
36 d -> 36.000000
pavilion: {236}
The difference between the last two printf statements points out, I
think, that a problem exists around printf. Might be float to double
conversion.
The difference between the second and fourth printf statements points
out that a problem exists in arithmetic. (dd and ddd should be equal.)
The latter problem is the more urgent one for me.
Thanks for any help at all..
Danny
P.S. All the code (tweaked gcc, binutils, etc) is in the SVN of the
cegcc project at http://sf.net/projects/cegcc .
--
Danny Backx ; danny.backx - at - scarlet.be ; http://danny.backx.info
