Floating point emulation support policy

[chenguokai17 at mails.ucas.ac.cn]



> 在 2021年3月31日，下午1:05，Anup Patel <Anup.Patel at wdc.com> 写道：
> 
> 
> 
>> -----Original Message-----
>> From: opensbi <opensbi-bounces at lists.infradead.org> On Behalf Of Xim
>> Sent: 30 March 2021 08:14
>> To: opensbi at lists.infradead.org
>> Subject: Floating point emulation support policy
>> Hi all,
>> My institution wants to run GNU/Linux distributions on a RISC-V core without
>> hardware floating point support. We used Berkeley Boot Loader (BBL) before
>> which has a built-in support for soft floating point emulation. We are
>> swtching to OpenSBI but no such emulations seem to exist in OpenSBI for
>> now. I wonder if OpenSBI would be happy to accept a port of such functions.
> 
> The suggestion of adding floating point emulation in OpenSBI has been
> proposed to us quite a few times in past.
> 
> Instead of adding floating point emulation in OpenSBI, another option is
> to disable FP for Linux RISC-V kernel and compiler user-space using soft-float
> toolchain. This approach will perform much better as compared to OpenSBI
> trapping and emulating floating point instructions.
> 
> Regards,
> Anup

Got it, but still wonder if you plan to support running GNU/Linux distributions which by default compile all their (user-space) packages with RV64GC on hardwares with no FPU. It is not so realistic to recompile them with a soft-float toolchain.

Regards,
Guokai Chen

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