Date: Sat, 09 Sep 2017 21:25:01 +0200 From: Jan Beich <jbeich@FreeBSD.org> To: Warner Losh <imp@bsdimp.com> Cc: Jan Beich <jbeich@vfemail.net>, "freebsd-arm\@freebsd.org" <freebsd-arm@freebsd.org>, "freebsd-toolchain\@FreeBSD.org" <freebsd-toolchain@freebsd.org> Subject: Re: FCP-100: armv7 plan Message-ID: <lgln-1xpu-wny@FreeBSD.org> In-Reply-To: <CANCZdfondSykr1UM0CNTYpVr-6hzyROYn-C_jNC_%2BhO1r6SB2w@mail.gmail.com> (Warner Losh's message of "Sat, 9 Sep 2017 13:14:36 -0600") References: <CANCZdfrCwdVOGWunSAjuxHzGcqhuH24iRQg63rvPFXXSmm-C6Q__2138.43810274756$1504912296$gmane$org@mail.gmail.com> <ingr-3d62-wny@FreeBSD.org> <CANCZdfondSykr1UM0CNTYpVr-6hzyROYn-C_jNC_%2BhO1r6SB2w@mail.gmail.com>
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Warner Losh <imp@bsdimp.com> writes: > On Sat, Sep 9, 2017 at 1:05 PM, Jan Beich <jbeich@vfemail.net> wrote: > >> Warner Losh <imp@bsdimp.com> writes: >> >> > Greetings, >> > >> > This will serve as 'Last Call' for any objections to the plan to create >> an >> > armv7 MACHINE_ARCH in FreeBSD, as documented in FCP-0100. >> [...] >> >> Some ports want NEON support but FCP-0100 is vague about FreeBSD-specific >> differences between armv6 and armv7. Clang appears to enable NEON for all >> *-gnueabi* targets but I have no clue about GCC. Apparently, Android and >> Debian don't assume NEON on armv7. >> >> related: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221898 >> > > Yes. We are vague about it on purpose. Just like we're vague about MMX, > MMX2, etc on x86 because different processors can/want use different > things. Do you mean similar to how FreeBSD i386 is vague about not supporting real i386, only i486 or later? > The goal, if it doesn't work already, is for NEON to work if used, > but not be required, just like all the other optional features of a CPU. FreeBSD doesn't support detecting NEON at runtime unlike Linux. Do you mean at compile time? If so then the following probably needs to change $ cc -target armv7-unknown-freebsd12.0-gnueabihf -dM -E -</dev/null |& fgrep -i neon #define __ARM_NEON 1 #define __ARM_NEON_FP 0x4 #define __ARM_NEON__ 1
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