[Haskell-cafe] Annoyed at System.Random

Vincent Hanquez tab at snarc.org
Fri May 4 16:30:18 CEST 2012

On 05/04/2012 03:05 PM, Thomas DuBuisson wrote:
> Vincent uses gcc header files to get the AES instructions:
> Header files of:
>      #include<wmmintrin.h>
>      #include<tmmintrin.h>
> And later calls of:
>       x = _mm_aesenc_si128(m, K1);
> But currently you must know you have AESNI and use a flag:
>      cabal install cryptocipher -faesni
> But if you are wrong:
>      Illegal instruction (core dumped)
Of course that's expected as of now, since it's not finished and i had to push a 
new release (related to some significant performance improvement for 
RSA/DH/DSA), the code is there as a "technology preview".

But the goal is to turn unconditionally the AESNI "flag" when arch is x86 or 
x86_64, which in this case the implementation would rely on the runtime cpuid 
check to use the aesni fastpath or not.

> This is a great place to be - now we just take the CPU checking from
> intel-aes, make a switch between Vincent's C and Gladman (in haskell
> or out, I doesn't matter to me), graft on Ctr mode as specified then
> it's all about matching the current 'random' API.
Please don't take the intel-aes test implementation. it's skewed to just support 
since it basically testing for the cpu string "GenuineIntel".

The only necessary test is the cpuid 1 with ecx having the 25th bit set.
It should just work providing cpus other than intel have matching cpuid 1 layout
(which as far i'm concerned seems to be the case in most cases)


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