[fpc-devel] FPC for Linux-ARM

Henry Vermaak henry.vermaak at gmail.com
Wed Jan 19 17:13:41 CET 2011


On 19/01/11 15:56, Michael Schnell wrote:
> On 01/19/2011 12:03 PM, Felipe Monteiro de Carvalho wrote:
>> Some phones have hardware floating point, the majority not.
> I'm not in a position to estimate the counts of Android devices that
> have an FPU vs those that don't, or suggest that all relevant of them have.
>
> But AFAIK, when building the Linux Kernel for AR; chips without FPU, you
> can include an FPU simulation. With that the user software (other than
> slower execution) does not notice that there is no FPU. As this only
> costs some hundred bytes of memory, I do suppose that the Kernel for
> Android devices might be done in that ways.

It might, but afaik, it's not.  Probably because it's really expensive 
to trap the illegal instructions and emulate them.

There is another consideration, though: float abi.  You can build a 
toolchain that enables use of an fpu, but still passes floats in int 
registers or on the stack (-mfloat-abi=softfp).  This is how the android 
toolchain is configured.  I don't think fpc can do this, though.

Henry



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