lkml.org 
[lkml]   [2003]   [Sep]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: nasm over gas?
    From
    On Thu, Sep 04, 2003 at 10:57:12PM +0800, Michael Frank wrote:
    > On Thursday 04 September 2003 21:44, Yann Droneaud wrote:
    > >
    > > Using nasm for only one small piece of code would be a regression, imho.
    >
    > Concur, not worthwhile to start using a fairly unsupported tool in the kernel.
    >
    > As to using assembler, It is better to get rid of it but in special cases.
    > Todays compilers are the better coders in 98+% of applications, and if you
    > follow some of the discussions here on the list, you will be amazed what
    > people do with a C compiler - all portable and much more maintainable.

    The gcc optimized code for sure much better than I do, but gcc's
    optimization captabilities is for sure a joke compared to the guy how wrote
    2fish_86.asm (just have a look at the source). The assembler implementation
    is twice as fast as the C implemention we have in the kernel. Same is true
    for AES (although just 50% faster instead of 100%:
    http://clemens.endorphin.org/patches/aes-i586-asm-2.5.58.diff . That's gas
    btw. )

    > I guess your code should be 80-90% C and 10-20% assmbler. This will make it
    > up to 10 times a portable.

    The Twofish code is C but has hooks to use an asm backend in special cases
    (keysetup, en/decrypt). But a plain C version of twofish is already present
    in the kernel.

    > As to using nasm, note for gas and gcc 3.2+:
    >
    > + GAS does intel syntax too using the directive
    > .intel_syntax

    That's certainly nice to hear. At least some cut/pasting can be done :)

    Regards, Clemens
    [unhandled content-type:application/pgp-signature]
    \
     
     \ /
      Last update: 2005-03-22 13:48    [from the cache]
    ©2003-2011 Jasper Spaans. Advertise on this site