Port-powerpc archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: MKSOFTFLOAT for evbppc

On Sep 20, 2012, at 8:31 PM, Simon Burge wrote:

> Matt Thomas wrote:
>>> (Also, for the port page: does fp emulation via traps work?  Or is
>>> MKSOFTFLOAT the only way that can possibly work?)
>> Within the past 4 months or so, I added emulation of the FPU so you can
>> run without MKSOFTFLOAT=yes.
> It looks like we've still got the same FPU emulator from the Walnut
> (405GP) days.  Way back when (2001?), softfloat was orders of magnitude
> faster on a Walnut.  There's the timings for an awk command issued
> during a kernel build at the time:
>       emulate:       113.554u 2778.750s 52:30.75 91.7%
>       softfloat:       7.607u    1.447s  0:10.57 85.5%
> This was the only reason we did softfloat at the time.

On a P2020, a build.sh distribution for evbppc took 6.2% less time on a 
softfloat userland .vs. hardfloat userland with kernel-emulation.

10h55m32s (soft) vs. 11h38m50s (hard)

Home | Main Index | Thread Index | Old Index