[pacman-dev] Crypto algorithms

[Roman Kyrylych]

2007/4/10, Nagy Gabor <ngaba at petra.hos.u-szeged.hu>:
> > :S maybe i did something wrong at asmutils compile, but seems it is
> > not faster :S its slower.
> >
> Yes, I also found that asmutils is slower.
> (asmutils: OS = LINUX, KERNEL = 26, OPTIMIZE = SPEED, SYSCALL =
> KERNEL vs. coreutils 6.9-1 standard i686 AL package)
>
> asmutils:
> ---------
> real    0m1.473s
> user    0m0.734s
> sys     0m0.302s
>
> coreutils:
> ----------
> real    0m1.103s
> user    0m0.194s
> sys     0m0.035s

This means that asmutils use slower algorithm.
The _same_ code written in C and assembler cannot be slower in
assembler by definition.
One cannot made C code faster by _just_ rewriting it in assembler, but
assembler allows better processing using internal registers, and
easier use of MMX/SSE/etc.
Correct use of assembler (not just "let's rewrite it in asm because
it's faaaast!!!") does make code faster.

-- 
Roman Kyrylych (Роман Кирилич)