FeepingCreature
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Re: Toolchain

Thu Jan 19, 2012 4:23 pm

A couple of dev-related questions?

What are the appropriate flags for gcc-configure (--target), gcc, as (-meabi) to build code that will be binary-compatible to the eventual default image for the RazPi?

Are the Broadcom GLES drivers API-compatible with MESA compiled for GLES/EGL?

Is there any chance you could make a "queue up for shell access to an actual razpi" thread, so we can test our programs before the release hits?

jamesh
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Re: Toolchain

Thu Jan 19, 2012 4:59 pm

I used the following when doing some basic benchmarking -O3 -mfloat-abi=softfp And yes, I think the API to the GL libraries is the same as MESA. It's designed to be a drop in replacement for the software renderer. 
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FeepingCreature
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Joined: Thu Jan 19, 2012 4:17 pm

Re: Toolchain

Thu Jan 19, 2012 8:01 pm

Thanks. Related question. I have this GLES test code: http://paste.pocoo.org/show/537361/

When I compile it for x86 (Mesa/i965), it renders a red window as expected. When I attempt to run it in qemu, it just renders a white window. Any idea what the problem could be?

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spennig
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Re: Toolchain

Thu Jan 19, 2012 8:12 pm

Perhaps qemu does not emulate the necessary 3d hardware?

richard77
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Re: Toolchain

Thu Jan 19, 2012 8:38 pm

JamesH said:

I used the following when doing some basic benchmarking -O3 -mfloat-abi=softfp And yes, I think the API to the GL libraries is the same as MESA. It's designed to be a drop in replacement for the software renderer.


I use gentoo, which is a source based distribution, and the documentation discourage to use -O3 since it can produce not working binaries and it tends to give bigger code, reducing cache efficiency , so often the code is actually slower compared to -O2. On processors with small cache, -Os gives better performances. Anyway, I plan to get on R-Pi, probably at the second batch and I hope to install Gentoo on it and will test and report.

jamesh
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Re: Toolchain

Thu Jan 19, 2012 10:01 pm

On the tests I was doing it did help quite a bit, but it will depend - the  programs I tested were pretty small anyway. All the binaries worked anyway!

There was another setting I failed to use when I was doing my builds that made things a lot faster, and I appears not to have noted it down - sorry.

-mcpu=arm1176jzf-s

might help as well.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed.
I've been saying "Mucho" to my Spanish friend a lot more lately. It means a lot to him.

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