[uClibc]Bonehead floating-point question

David Wuertele dave-gnus at bfnet.com
Thu Mar 13 18:39:34 UTC 2003


OK, I have a totally basic floating-point question for y'all.

I've been trying to compile everything "soft float" and I've been
having a lot of trouble.  Now I find out about the floating point
emulator that comes with every kernel.  In fact, my kernel has that
compiled in by default, and reports "Algorithmics/MIPS FPU Emulator
v1.5" when it boots.

What is the relationship between compiling for my target with
-msoft-float and the target kernel's floating point emulator?  If I've
got an emulator, why should I do anything with soft floats?

For example, uClibc Configuration asks at one point:

  Target CPU has a floating point unit (FPU) (HAS_FPU) [Y/n/?] y

Why should it care?  As a matter of fact my target CPU does *not* have
an FPU, but since I've got emulation it shouldn't matter.  What do I
gain/loose by saying "n" here?

The default buildroot builds gcc "--without-float" ... Why is that
needed?

Thanks,
Dave




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