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Yann, Khem, All, On Sat, Nov 13, 2010 at 10:56 AM, Yann E. MORIN <yann.morin.1998@anciens.enib.fr> wrote: > Bryan, Khem, All, > > On Saturday 13 November 2010 19:09:18 Bryan Hundven wrote: >> > The patch is needed for a toolchain configured with old ABI (oabi) and >> > soft float >> > as old abi is stale and obsolete upstream gcc has no interest in this >> > patch. that said >> > you dont need it if you do not build oabi toolchains. Most of stuff >> > these days use eabi >> > and eabi toolchains dont require it. Does ct-ng supprt oabi toolchains ? > > Yes, crostool-NG still has the ability to build OABI toolchains. > I know that OABI is deprecated, but there are still systems out > there that use OABI, and for which upgrading to EABI is simply > not feasible. > >> It may be interesting to know now if Michel's ctng config had eabi turned >> off. > > The tuple for Michael's toolchain was arm-cortexa8-linux-gnu which means > it is OABI. > >> I know that eabi is a boolean option, that defaults to 'y', but can be disabled. >> So I would assume that oabi is still possible with crosstool-ng. > > Yes. > >> I have a question about the "-lfloat" in the gcc/config/arm/linux-elf.h. >> I thought that libfloat was provided by the netwinder floating point >> emulation, but on modern (gcc > 4.1) toolchains, I don't see any >> reference to libfloat except in gcc/config/arm/linux-elf.h. Am I >> missing something? > > Googling for "netwinder floating point emulation" gives: > Âhttp://netwinder.osuosl.org/users/s/scottb/public_html/notes/FP-Notes-all.html > > Which sends us to: > Âhttp://www.eecs.berkeley.edu/~jhauser/arithmetic/softfloat.html > which is now 404. > > Anyway, the latest release of the SoftFloat library was release 2b, dating > back to May 2002: > Âhttp://www.jhauser.us/arithmetic/SoftFloat.html > > For my part, I wonder why gcc still has reference to -lfloat, when there are > available softfloat functions bundled with gcc. Are we not supposed to use > them? If so, why are they present in the first place? Well... Looking through the gcc commit log, I found CL 113056 where soft-fp was added from glibc by Joseph Myers (originally only rs6000 was supported) and CL 132837 Paul Brook added soft-fp support for arm in t-arm-softfp, but disabled for every platform except ARMv6-M(?). I don't see any newer commits that actually enable the gcc's soft-fp for any other arm architecture. So if I understood that correctly, it sounds like all other arm architectures are getting soft float from libm, or are expected to have libfloat from(?): http://netwinder.osuosl.org/users/s/scottb/libfloat/ (I believe this was the source you were looking for and not "The SoftFloat Library", although I might be wrong. See: http://netwinder.osuosl.org/users/s/scottb/public_html/notes/FP-Notes-6.html) ...which is 11 years old! Anyways, I hope this info is somewhat close to accurate and useful to someone. It might be useful to ask these questions again on gcc-help, as I'm sure someone with an oabi arm toolchain is going to bring this up again in the future. > Regards, > Yann E. MORIN. > > -- > .-----------------.--------------------.------------------.--------------------. > | ÂYann E. MORIN Â| Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: | > | +33 662 376 056 | Software ÂDesigner | \ / CAMPAIGN   | Â___        | > | +33 223 225 172 `------------.-------: ÂX ÂAGAINST   Â| Â\e/ ÂThere is no Â| > | http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL  Â|  v  conspiracy. Â| > '------------------------------^-------^------------------^--------------------' > > > -Bryan -- For unsubscribe information see http://sourceware.org/lists.html#faq
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