On 12/11/15 17:03, Mark Hatle wrote: > On 11/12/15 3:17 AM, Toby Gomersall wrote: >> Hi, >> >> I want to build yocto with hard float support. I understand that I can >> point the EXTERNAL_TOOLCHAIN variable at the appropriate external hard >> float compiler (gcc-5-arm-linux-gnueabihf). However, I was wondering if >> there was anything within the yocto project to do this? > > I'm going to be pedantic for a second.. bear with me. > > ARM has two ABIs, the standard EABI which passes floating point values via > integer registers and EABIHF that passes floating point values via floating > point registers. > > EABI allows hardware floating point along with neon or any other core specific > optimizations. > > EABIHF requires a specific set and size of VFP registers. > > The Yocto Project is capable of building for both ABIs with whatever > combinations of optimizations you need. > > The ABI and default processor optimization is configured by the 'DEFAULTTUNE' > parameter. This is typically defined in your machine configuration file, > either > explicitly or implicitly via the including of the tune files. > > > So for example, if you have an ARMv5 CPU you would likely use: > > DEFAULTTUNE="armv5e" > > This would select ARM EABI, no VFP. > > alternatively you could do: > > DEFAULTTUNE="armv5e-vfp" > > This would select ARM EABI w/ VFP floating point. > > OR > > (what I think you are actually trying to ask) > > DEFAULTTUNE="armv5ehf-vfp" > > This would select ARM EABIHF w/ VFP floating point. > > > So start with your machine and determine which defaulttune (bitbake -e) you > have > selected. Adjust it to a compatible setting for the ABI and processor > optimizations that you wish to use. > >> I'm concerned that future updates to an external compiler might affect >> my build and I would prefer to use a method from within the yocto project. > > Unless you have a specific need, I don't recommend external compilers. The > Yocto Project compilers and configurations are well tested and high quality. > While using an external compiler is support by some vendors, it adds > complexity > that may not be beneficial. (Sometimes support and other aspects of > commercial > offerings outweigh the complexity..) > >> Thank you, >> Toby >> >> >> >
Thank you very much for your help, that was exactly what I was looking for.
signature.asc
Description: OpenPGP digital signature
-- _______________________________________________ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto
