Hi, I have been porting mozilla firefox to the SH4 platform. However, I have
run into some horrible floating point problems.
details:
gcc 4.1.0
glibc 2.3.6
(built using crosstool)
firefox 1.5.0.4
linux kernel 2.6.11
Running on an STB7100 with SH4-202 processor core (yes it does have an FPU).
I have been trying to make a small test case to illustrate the problem.. but I
cannot seem to manage it. It seems to be a prerequisite that I must have the
massive mozilla XPCOM shared libraries loaded or something.
Anyway, I manged to get my test code down to:
int main()
{
// printf("HELLO\n");
int x = 20;
float k = (float) x;
NS_InitXPCOM2(nsnull, nsnull, nsnull);
printf("THERE\n");
}
I also have debug prints inside NS_InitXPCOM2.
Basically if I leave the HELLO printf commented out, I do not see the debug in
NS_InitXPCOM2(). Instead I get a "floating point exception".
If I uncomment it I *do* see the debug (althought it later gets another FP
exception; this is the problem I'm really trying to solve).
If I comment out the call to NS_InitXPCOM2() it runs fine.
As far as I can make out it is NOT the NS_InitXPCOM2() itself which is failing
since it outputs my debug if I have the first printf uncommented.
If I add more trace elsewhere the problem sort of shifts about... it sounds
like some form of alignment problem to me.
Oh, I also tried creating my own shared library with an NS_InitXPCOM5() method
and calling that instead... that worked fine.
Can anyone advise a way I can try and work out what is going on to provide a
small example that _doesn't_ involve calling into mozilla XPCOM?
I can always provide the binaries and source if people want it.. but mozilla
is _huge_.
Oh, my test file was compiled with:
sh4-unknown-linux-gnu-gcc -o TestXPC.o -c -O0 \
-DMOZILLA_INTERNAL_API -DOSTYPE=\"Linux\" -DOSARCH=\"Linux\" \
-I../../../../dist/include/xpconnect \
-I../../../../dist/include/xpcom \
-I../../../../dist/include/js \
-I../../../../dist/include/nspr \
-fPIC \
/etv/branches/aminet130/scratch/amino-stb710x-mozilla/mozilla/js/src/xpconnect/tests/TestXPC.cpp
and linked with:
sh4-unknown-linux-gnu-gcc \
-o TestXPC \
TestXPC.o \
-L../../../../dist/bin -lxpcom -lxpcom_core \
-L../../../../dist/lib -lplds4 -lplc4 -lnspr4 \
-lpthread -ldl -ldl -lm -lsupc++
