Enabling soft-fp on x86 (Not cross compiler)

[Aed]

Hi,

I'm trying to use the gcc flag "-msoft-float" in order to instrument and profile use of FP code in my project. The compiler generates the appropriate stubs, however glibc doesn't compile the "soft-fp" module by default on x86. How can I force this?

Thanks,
Aed

[NeddySeagoon]

Aed,

Welcome to gentoo

gcc never provides the software floating point emulation when you use "-msoft-float". On arm at least, you have to make your own arrangements.

On x86, the floating point emulation is provided in the kernel. It traps x86 FPU instructions and emulates them. However, building the kernel with software floating point enable is not enough as the kernel will use the real FPU if its fitted. You need to provide the kernel option that tells the kernel your FPU is faulty and not to use it.

Doing software floating point this way means that binaries compiled to expect a real FPU just work, only much slower.
_________________
Regards,

NeddySeagoon

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[Aed]