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On Mon, Aug 16, 2004 at 12:28:38AM +0200, Dimitry Andric wrote: > > Runtime switching between VFP and FPA seems to be about as useful to > > me as being able to switch between ELF and COFF at runtime. Why can't > > you tell people to just hack gcc's header files and recompile, or > > make it a gcc build-time option (as parameter to configure or so)? > > Well, there are some uses for it, and the best example I think is the > ARM Linux kernel itself, which uses -msoft-float everywhere. Shouldn't we then just have an option -mdont-emit-fpu-instructions-at-all for this? (Like, -mno-fpu?) > Indeed, > as you say later on, this is more about what the defaults are if you > don't specify anything. And I agree that should probably be hardware > FPA, for various reasons, which have already been discussed. Yup. > >> arm-unknown-linux-gcc without options generates hardware FPA. > >> arm-unknown-linux-gcc -msoft-float generates software FPA. > >> arm-unknown-linux-gcc -mhard-float generates hardware FPA, i.e. the > >> same as without options! > > > This makes sense to me, though, since you get the same behaviour with > > many other options, like the ones of the form -f{,no-}some-option (for > > example, -f{,no-}strict-aliasing.) > > But please, let's not introduce -mno-soft-float etc, because we'll all > go crazy with confusion. ;) no-soft-float = hard-float? uhhhmmm... :) > > My thought right now is that fpa/vfp should be fixed at gcc compile time. > > Do you have any compelling reasons why this shouldn't be so? :) > > Yes, that is quite reasonable. Once you're on a certain platform, > you'll never switch it anymore anyway. Then again.. and sorry to contradict myself here.. the endianness on the ARM platform is also settable at compile time.. so what _is_ the right criterion here? One could also argue that one should be able to compile code for all ARM targets with the same ARM compiler binary. -mbig-endian/-mlittle-endian -mfloat-format=vfp/-mfloat-format=fpa -mfloat=hard/-mfloat=soft/-mfloat=off Too many options :( --L ------ Want more information? See the CrossGCC FAQ, http://www.objsw.com/CrossGCC/ Want to unsubscribe? Send a note to crossgcc-unsubscribe@sources.redhat.com
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