2011/10/3 Steve McIntyre steve.mcintyre@linaro.org:
On Mon, Oct 03, 2011 at 12:33:04PM +0200, Jeremiah Foster wrote:
On Mon, Sep 26, 2011 at 8:37 PM, Jon Masters jcm@redhat.com wrote:
[ Please forward this to anyone else who should get a copy - and ask them to signup to cross-distro@linaro because that's where we'll talk ]
Folks,
At the 2011 Linux Plumbers Conference in Santa Rosa, we held an ARM minisummit to discuss a few cross-distribution issues surrounding the "hard float" ABI for v7, and the ARM device and OS ecosystem in general. This mail is intended to summarize the key actions from that meeting.
Thanks very much Jon and others for the work towards consensus and a bit of standardization. I'm certain this will help going forward.
Thanks also everyone for the communication on this list, I find it very valuable.
I'd very much like to contribute to the LSB testing on ARM and I'll keep an eye out on this list to see if there is more information on how that work will be organized. (I think Mats Wichman at the Linux Foundation knows a bit more so it ought to be coordinated with him going forward perhaps.)
I think I am in the "free software zealot" position here :-)
So, a few minutes ago I was pointed to http://wiki.meego.com/Hardware-accelerated_graphics_on_Pandaboard_using_MeeG... that points to http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0041c/Babdhhd...
or for some related information http://groups.google.com/group/pandaboard/browse_thread/thread/cd69411c1cb60...
For now I have been only considering gcc as compiler, and the link in infocenter.arm.com appears to suggest that the mapping, to have an armv7 distro capable of running existing armv5 or older software, would be:
gcc -mfloat-abi=softfp -mfpu=vfpv3-d16 -> tcc /hardfp /nofpregargs
possibly replacing vfpv3-d16 with neon
but the problem is, the tcc (arm C compiler!?) calls softfp what gcc calls -mfloat-abi=soft, but "now" only supports hardp with what gcc calls -mfloat-abi=hard calling convention.
/fpregargs Floating-point arguments are passed in floating-point registers. This option is not available for in tcc or tcpp, and is the default for ARM if /hardfp is selected. /nofpregargs Floating-point arguments are not passed in floating-point registers. This option is not available in tcc or tcpp. This option is obsolete and is available for backwards compatibility only.
Note, that "tcc" issues is news to me, as so far I was only considering gcc and its optimizations that make breaking the abi pretty much nonsense, but was not considering an extra compiler, that may be being used to build external, non open source libraries, e.g. libGLes*.
Jon and I have both been talking to Mats and Jeff about LSB already, but things have gone a little quiet while we've been concentrating on bringup in the last few months. They would definitely be the right people to work with going forwards...
Cheers,
Steve McIntyre steve.mcintyre@linaro.org http://www.linaro.org/ Linaro.org | Open source software for ARM SoCs
Paulo