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Author Topic: Timing graphs for ARM asm memcpy  (Read 4678 times)

Offline TP Diffenbach

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Timing graphs for ARM asm memcpy
« on: July 09, 2006, 01:39:27 PM »
Please examine this page of timings, which compares the time cost of four memcpy implementations:
http://diffenbach.org/rockbox/memcpy/memcpy.comparison.0.256.html

And let me know if you think my memcpy is fast enough to be used instead of the uclinux memcpy.

uclinux is (slightly) faster for some small unaligned copies with copy lengths evenly divisible by powers of two. Mine is faster for any copies of lengths > ~ 56 bytes.

Thanks.
« Last Edit: July 09, 2006, 02:16:25 PM by TP Diffenbach »
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Note: My use of rockbox tends to be limited to just playing music; I don't use fancy themes, or graphic equalizers, or playlists, or most plugins. So I may not notice when those things don't work, or if a patch of mine interferes with those things; if so, point that out to me.

Offline Bagder

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Re: Timing graphs for ARM asm memcpy
« Reply #1 on: July 09, 2006, 01:53:56 PM »
I think you and your version just rock! ;-)
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Offline TP Diffenbach

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Re: Timing graphs for ARM asm memcpy
« Reply #2 on: July 09, 2006, 02:15:56 PM »
Thanks. What we really need to do is discover how mmecpy is being called, esp. for unaligned copies. But I'm going to let someone else do that.



« Last Edit: July 09, 2006, 05:20:03 PM by TP Diffenbach »
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Note: My use of rockbox tends to be limited to just playing music; I don't use fancy themes, or graphic equalizers, or playlists, or most plugins. So I may not notice when those things don't work, or if a patch of mine interferes with those things; if so, point that out to me.

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