[RC5] Client for Windows/64Bit

Fuzzy Logic fuzzymo at gmail.com
Mon Aug 15 22:52:30 EDT 2005

Ah, that could provide a large improvement in performance for x86 then.

I work on zSeries machines, and they've always had a separate PSW
(like the IP/EIP register on x86) and 16 registers (r0-r15), and have
always been 32-bit registers.

With the z990, all 16 registers were extended to 64 bits, and new
hardware instructions for crypto were added: KM/KMC (DES ECB/CBC), and
KIMD/KLMD (SHA-1), with newer ones to be added with later hardware
(just announced for the z9: KM/KMC (AES-128), KIMD/KLMD (SHA256), and

Probably more that you care to know, but this is the sort of stuff I work with.


On 8/15/05, Décio Luiz Gazzoni Filho <decio at decpp.net> wrote:

> Well that's the point. x86-64 has 16 registers while ordinary x86 has
> 8. (actually one is the stack pointer, so it's more like 15 vs. 7).
> There's the source of extra performance in x86-64.
> On Aug 15, 2005, at 10:50 PM, Fuzzy Logic wrote:
> > Same number of registers, but each is twice as long.

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