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On Thu, Oct 20, 2011 at 10:02 AM, Yann E. MORIN <yann.morin.1998@anciens.enib.fr> wrote: > Michael, All, > > On Wednesday 19 October 2011 04:29:20 Michael Hope wrote: >> # HG changeset patch >> # User Michael Hope <michael.hope@linaro.org> >> # Date 1318991252 -46800 >> # Node ID a31d097e28cd73d07a5484129929a500b4d58efa >> # Parent ?a32156bd31c0d395e8d346431b123a7d2caa14cd >> scripts: add softfp support >> >> ARM compilers can be built for soft float (software only, floats in >> core registers), hard float (uses floating point instructions, floats >> in FPU registers), or the half-way house softfp (uses floating point >> instructions, floats in core registers). > > Feature definitely a nice addition, but too close to the release to > add it now (which reminds me I should document the release plan on > the website...). FYI, it's a release every three months, with about > a 15-day slack before, used to stabilise the stuff. Next release is > due by October the 31st, so we just entered the 15-day delay... > > I was thinking about cutting the release branch ahead of time, but > handling both the relase and the devel at the same time is a bit > complicated in my head, and does colide a bit on the schedule... > I'd like to try, but this release is special: it also colides with > the Prague events. Probably I'll do it for the next release (Feb`12)... All good. I'll keep it local for now. >> Add support for softfp cross compilers to the GCC and GLIBC >> configuration. ?Needed for Ubuntu and other distros that are softfp. > > What about uClibc? How will it cope with softfp? I'm not sure. I've had a poke about in buildroot and it has support for soft float and hard float but no softfp. It seems to tie the FPU into the calling convention like crosstool-NG currently does so hard float == has VFP. I can play with this more next week. >> Signed-off-by: Michael Hope <michael.hope@linaro.org> >> >> diff -r a32156bd31c0 -r a31d097e28cd config/target.in >> --- a/config/target.in ? ? ? ?Sun Oct 16 17:51:42 2011 +0200 >> +++ b/config/target.in ? ? ? ?Wed Oct 19 15:27:32 2011 +1300 >> @@ -271,6 +271,22 @@ >> ? ? ? ?If your processor has no FPU, then you most probably want this, as it >> ? ? ? ?is faster than emulating the FPU in the kernel. >> >> +config ARCH_FLOAT_SOFTFP > > I'm a bit reluctant at adding an architecture-specific option to this > generic file. Currently, all arch options are in the related arch file. > > However, I agreee that there is no easy way to nicely handle that with > the current infrastructure... :-/ > > *But* I recall a similar approach a few months back... It seemed that ARM > is not the only architecture that support softfp. Seems PPC also uses it. > So: > >> + ? ?bool >> + ? ?prompt "softfp" >> + ? ?depends on ARCH_arm > > ?- this arch-specific "depends on" should go away > ?- and either we keep the option un-protected, or we hide it behind > ? ARCH_SUPPORT_SOFTFP (or the like) which is set by archs that > ? support it. OK. >> + ? ?help >> + ? ? ?Emit hardware floating point opcodes but use the software >> + ? ? ?floating point calling convention. >> + >> + ? ? ?Architectures such as ARM use different registers for passing >> + ? ? ?floating point values depending on if they're in software mode >> + ? ? ?or hardware mode. ?softfp emits FPU instructions but uses the >> + ? ? ?software FP calling convention allowing softfp code to >> + ? ? ?interoperate with legacy software only code. >> + >> + ? ? ?If in doubt, use 'software' or 'hardware' mode instead. >> + >> ?endchoice >> >> ?config TARGET_CFLAGS >> diff -r a32156bd31c0 -r a31d097e28cd scripts/build/libc/glibc-eglibc.sh-common >> --- a/scripts/build/libc/glibc-eglibc.sh-common ? ? ? Sun Oct 16 17:51:42 2011 +0200 >> +++ b/scripts/build/libc/glibc-eglibc.sh-common ? ? ? Wed Oct 19 15:27:32 2011 +1300 >> @@ -132,9 +132,10 @@ >> ? ? ? ? ?*) extra_config+=("--disable-shared");; >> ? ? ?esac >> >> - ? ?case "${CT_ARCH_FLOAT_HW},${CT_ARCH_FLOAT_SW}" in >> - ? ? ? ?y,) extra_config+=("--with-fp");; >> - ? ? ? ?,y) extra_config+=("--without-fp");; >> + ? ?case "${CT_ARCH_FLOAT_HW},${CT_ARCH_FLOAT_SW},${CT_ARCH_FLOAT_SOFTFP}" in >> + ? ? ? ?y,,) extra_config+=("--with-fp");; >> + ? ? ? ?,y,) extra_config+=("--without-fp");; >> + ? ? ? ?,,y) extra_config+=("--with-fp");; >> ? ? ?esac > > Argh!... This is starting to be unreadable... :-/ > > config ARCH_FLOAT > ? ?string > ? ?default "hard" ? if ARCH_FLOAT_HW > ? ?default "soft" ? if ARCH_FLOAT_SW > ? ?default "softfp" if ARCH_FLOAT_SOFTFP > > Then: > ? ?case "${CT_ARCH_FLOAT}" in > ? ? ? ?hard) ? ...;; > ? ? ? ?soft) ? ...;; > ? ? ? ?softfp) ...;; > ? ?esac > > I'll do it. OK. >> ? ? ?if [ "${CT_LIBC_DISABLE_VERSIONING}" = "y" ]; then >> diff -r a32156bd31c0 -r a31d097e28cd scripts/functions >> --- a/scripts/functions ? ? ? Sun Oct 16 17:51:42 2011 +0200 >> +++ b/scripts/functions ? ? ? Wed Oct 19 15:27:32 2011 +1300 >> @@ -984,6 +984,7 @@ >> ? ? ?[ "${CT_ARCH_TUNE}" ? ? ] && { CT_ARCH_TUNE_CFLAG="-mtune=${CT_ARCH_TUNE}"; ?CT_ARCH_WITH_TUNE="--with-tune=${CT_ARCH_TUNE}"; } >> ? ? ?[ "${CT_ARCH_FPU}" ? ? ?] && { CT_ARCH_FPU_CFLAG="-mfpu=${CT_ARCH_FPU}"; ? ? CT_ARCH_WITH_FPU="--with-fpu=${CT_ARCH_FPU}"; ? ?} >> ? ? ?[ "${CT_ARCH_FLOAT_SW}" ] && { CT_ARCH_FLOAT_CFLAG="-msoft-float"; ? ? ? ? ? CT_ARCH_WITH_FLOAT="--with-float=soft"; ? ? ? ? ?} >> + ? ?[ "${CT_ARCH_FLOAT_SOFTFP}" ] && { CT_ARCH_FLOAT_CFLAG="-mfloat-abi=softfp"; CT_ARCH_WITH_FLOAT="--with-float=softfp"; ? ? ? ?} > > And the last time this came up, it was pointed that CT_ARCH_FLOAT_HW did > force neither -hard-float not --with-float=hard > > I'll look at it... OK. > Can we sit on this for now, and revisit after the release? Sure. I'll keep it locally. -- Michael -- For unsubscribe information see http://sourceware.org/lists.html#faq
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