Re: Floating point performance (was Re: compiling LUA for uClinux)

["Adam D. Moss" <adam@...>]

Luiz Henrique de Figueiredo wrote:
> > Just FYI, converting from float to int is more expensive on an x86 machine
> > than many people realize, if you're using casts to convert.
>
> Since 5.0, Lua can be configured to use a fast conversion method.
> Lua 5.1 even tries to do this automatically.

That's neat, I hadn't noticed.

On a similar note, poking around in luaconf.h I tried turning
lua_number2str()'s sprintf() into a gcvt() to see if that
gained anything.  But it was actually slightly slower than
sprintf() (which was a bit surprising because intuitively sprintf
has to do more work, but sprintf has probably been subject to more
optimization).

--Adam
--
Adam D. Moss   -   adam@gimp.org