Re: x86 SHA1: Faster than OpenSSL

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On Wed, 5 Aug 2009, George Spelvin wrote:
> 
> > We can continue shipping mozilla one to help the last group.
> 
> Of course, we always need a C fallback.  Would you like a faster one?

I actually looked at code generation (on x86-64) for the C fallback, and 
it should be quite doable to re-write the C one to generate good code on 
x86-64.

On 32-bit x86, I suspect the register pressures are so intense that it's 
unrealistic to expect gcc to do a good job, but the Mozilla SHA1 C code 
really seems _designed_ to be slow in stupid ways (that whole "byte at a 
time into a word buffer with shifts" is a really really sucky way to 
handle the endianness issues).

So if you'd like to look at the C version, that's definitely worth it. 
Much bigger bang for the buck than trying to schedule asm language and 
having to deal with different assemblers/linkers/whatnot.

		Linus
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