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The netwinder is using "NWFPE", the kernel floating point emulator, to do the floating point stuff.
When I cross-compile (on x86linux to arm) I can get the correct code generated if I specify -mhard-float. ... So my problem is really that the crosstool build does not seem to be able to build glibc with "hard float" so that the linked binary (built using the cross-compiler) is compatible with the NWFPE libc.so on the netwinder.
Did you try adding -mhard-float to TARGET_CFLAGS in arm.dat before building crosstool? ...
I am using crosstool-0.27, and my current ".dat" file looks like this:
KERNELCONFIG=$PWD/arm.config TARGET=arm-elf-linux TARGET_CFLAGS="-march=armv4 -O" GCC_EXTRA_CONFIG="--with-float=hard"
I had problems in the distant past with gcc defaults in GCC_EXTRA_CONFIG not applying for the glibc or stdlibc++ built by crosstool, so it might be worth also setting TARGET_CFLAGS="-march=armv4 -O -mhard-float" in that file.
The problem I am having is that evidently the netwinder requires the "hard-float" configuration of gcc, but I cannot compile glibc without the "--without-fp" option, and thus it is not possible to link executables with the cross toolchain.
I should point out that I CAN build working floating point programs as long as I build just the object using the crosstool-built GCC specifying -mhard-float on the command line and then link it on the netwinder.
Right now, I am trying the approach of commenting out the missing instructions (e.g. sfmea) in the glibc sources. This might work and I will keep you posted. But is there a better approach?? Is there some legit configuration settings I can use to build the unadulterated glibc sources for the netwinder?
Hrm, I dunno. I wonder if there are any interesting patches in ftp://fr2.rpmfind.net/linux/netwinder.org/netwinder/SRPMS/base/nw9/glibc-2.3.2-27.9_nw3.src.rpm Have you looked in glibc cvs to see if the missing instructions are used? Why are the instructions missing? Do we need to configure binutils differently? - Dan
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