Messages in this thread | | | Date | Mon, 1 Nov 2004 12:51:43 -0800 (PST) | From | dean gaudet <> | Subject | Re: [rc4-amd64] RC4 optimized for AMD64 |
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On Mon, 1 Nov 2004, dean gaudet wrote:
> On Mon, 1 Nov 2004, Marc Bevand wrote: > > > I have just published a small paper about optimizing RC4 for > > AMD64 (x86-64). A working implementation is also provided: > > > > http://epita.fr/~bevand_m/papers/rc4-amd64.html > > > > Kernel people may be interested given the fact that Linux > > already implements RC4. > > you've made a non-portable flags assumption: > > > dec %r11b > > ror $8, %r8 # (ror does not change ZF) > > jnz 1b > > the contents of ZF are undefined after a rotation... most importantly > they differ between p4 (ZF is set according to result) and k8 (ZF > unchanged).
ack... it's too early on a monday morning -- i misread the documentation. this ZF assumption is actually defined and portable... still kind of ugly. how much benefit do you see?
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