[ogg-dev] OggPCM: support for little-endianness only?

Erik de Castro Lopo mle+xiph at mega-nerd.com
Wed Feb 13 00:02:35 PST 2008


Jean-Marc Valin wrote:

> Really? How low does it take to swap bytes vs. the time it takes to read
> from disk?

In CPU cycles? The difference is enormous.

If no byte swapping is required the vast majority of the work is done by
the DMA engine, from disk straight into user space memory and while the
read is underway, the CPU can do other work.

For the byte swapping case, every sample needs to be loaded into the cache
and CPU, byte swapped and then written back to memory.

Erik
-- 
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Erik de Castro Lopo
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I have now spent two days debugging C# on dotnot and all I can say
is OMFG!!!! The MS tools are completely fucking abysmal. Its the
most developer hostile environment I've ever worked on. The fact
that people are actually able to release software that sort of
works using these tools completely boggles my mind.


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