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Re: [ts-7000] Re: TS-7800 Floating Point Performance

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Subject: Re: [ts-7000] Re: TS-7800 Floating Point Performance
From: Bob Lees <>
Date: Wed, 6 Feb 2008 13:18:27 +0000
>From memory, I think that EABI systems are supposed to have binary 
compatibility with non-eabi binaries, but I could never make that work.  

Out of the box the cross compiler builds float to use the kernel floating 
point emulator which is supposed to be and at the last count was somewhat 
faster than the non-eabi emulator.  

If you want to use soft-float then you need a cross-compiler which has been 
built for soft-float support which is NOT the default

AFAIK the current Marvell chip on the 7800 does not have native floating point 
support and as you point out Maverick Crunch is Cirrus specific.

I was using arm-2005q3-2-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2 to 
build my eabi binaries for hard float (kernel emulation).

Hope this helps

Bob

On Wednesday 06 February 2008 02:54:18 delapluie wrote:
> all right, I just discovered this thread-
>
> http://tech.groups.yahoo.com/group/ts-7000/message/9683
>
> which seems to indicate that the 7800 ships with an OABI kernel.  But
> when I try readelf -h /bin/ls on my two day old TS-7800, I get this-
>
> ELF Header:
> ...
>   Flags:                             0x2, has entry point, GNU EABI
>
> Which sure suggests it is EABI to me.  Is it possible that I will get
> better performance than the native compiler if I can get one of the
> EABI cross compilers to work?
>
> -mike
>
> --- In  "delapluie" <> wrote:
> > I recently got a TS-7800, in the hope that because of the EABI support
> > and the 500 MHz processor, it would perform much better at floating
> > point math than the 7260 I was testing before.
> >
> > I was unsuccessful in getting the crosstools to work from Ubuntu.
> > When I ftp'd my executable to the 7800, and did a "chmod +x test", I
> > keep getting-"-bash: ./test: No such file or directory"  If anyone has
> > any thoughts on this problem, I'd appreciate it.
> >
> > But I'm really eager to determine if the 7800 can solve my performance
> > problem, so I ftp'd my source code over, and compiled it natively on
> > the 7800.  No compiler options (do I need any?)
> >
> > Strangely, benchmarking 1000 iterations of my algorithm, I got almost
> > exactly the same performance as with the 7260- about 54ms per
> > iteration.  I expected that even if EABI wasn't doing it's job, I
> > would at least get a 2.5 times speed up from the clock rate.  My test
> > code reads a line (maybe 100 bytes) from a data file in the NAND flash
> > once per iteration; otherwise, I can't think of anything outside the
> > processor that takes any time.
> >
> > Has anyone else benchmarked floating point on the 7800, and gotten
> > better results?  Any idea what I might be doing wrong?  Thanks,
> >
> > -Mike



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