Please distinguished the diff between soft and softfp. As Thiago said in below, " Maemo 5 builds with the Neon VFP but in soft-fp mode. That is, it uses the hardware for manipulating the floating point values, but parameters are passed in ARM GP registers." Maemo 5 is using soft-fp, it means if your HW supports vfp, it would use it but with compatibility with software implementation, that would definitely brings some performance lost but it DOES be hardware mode rather than pure software emulation.
For hard instead of softfp, with the update to gcc 4.5.0, it supports to do this, but not sure if or not there were any concerns on this kind of switch? -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Sivan Greenberg Sent: Thursday, August 05, 2010 4:45 PM To: Development for the MeeGo Project (discussion list) Subject: Re: [MeeGo-dev] ARM softfloat or hardfloat? So MeeGo is going to be hard-floart? That's surprising to learn that Maemo is actually soft flot, but could maybe account for the bits of sluggishness experienced? When I did a soft-float point port of debian for MIPS it had severe consequences on platform's performance compared to same SOCs with an FPU. -Sivan On Thu, Aug 5, 2010 at 8:25 AM, Zhang, Austin <[email protected]> wrote: > So any concern on switch softfp to hard? Meanwhile, what compiler is being > used for Maemo 5 build? Does it support Neon naturally? > > And as you may know, so far, we had switch compiler to 4.5.0, so seemed it is > also time to change those flags. > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Thiago Macieira > Sent: Thursday, August 05, 2010 12:09 PM > To: Development for the MeeGo Project (discussion list) > Subject: Re: [MeeGo-dev] ARM softfloat or hardfloat? > > On Wednesday 4. August 2010 20.15.35 Arjan van de Ven wrote: >> On 8/4/2010 2:36 PM, Jeremiah Foster wrote: >> > Hello, >> > >> > What is MeeGo planning to do with regards to ARM hardfloat or >> > softfloat? >> > What is the rationale behind the choice? >> > >> > Some background information here: >> > http://wiki.debian.org/ArmHardFloatPort >> > >> > Jeremiah >> >> it's my understanding that n900 supports hard float... so that's what >> we're using for the n900 builds... > > The N900 hardware (Cortex-A8) does support hard float. > > However, Maemo 5 builds with the Neon VFP but in soft-fp mode. That is, it > uses the hardware for manipulating the floating point values, but parameters > are passed in ARM GP registers. > > -- > Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org > Senior Product Manager - Nokia, Qt Development Frameworks > PGP/GPG: 0x6EF45358; fingerprint: > E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358 > _______________________________________________ > MeeGo-dev mailing list > [email protected] > http://lists.meego.com/listinfo/meego-dev > _______________________________________________ MeeGo-dev mailing list [email protected] http://lists.meego.com/listinfo/meego-dev _______________________________________________ MeeGo-dev mailing list [email protected] http://lists.meego.com/listinfo/meego-dev
