Mail Archives: djgpp/2010/11/25/17:45:50
Hi, note that I don't have any Atoms nor am I a professional
programmer, but ....
On Nov 25, 1:39=A0am, philippe <philippe DOT meyn DOT DOT DOT AT gmail DOT com> wrote:
>
> When I try my program on a CPU ATOM N270 @ 1,6Ghz, The program is very
> slow. Exemple : I Copy 32000 value in memory. On a cpu Celerom M
> @1,6Ghz it take 270 us and on ATOM it take 2856 us. My OS is FreeDos.
> the program is compiled with djgpp.
> Have you got an idea ?
http://en.wikipedia.org/wiki/Intel_atom
http://ark.intel.com/Product.aspx?id=3D36331
All I remember hearing was everybody comparing it to the 486 (in-order
execution), no superscalar, no out-of-order, just vaguely
"slow" ("fast P3 speeds at best"). At least that's what I heard, so I
could be wrong. Some of the newer ones are allegedly better, but
again, they aren't like typical desktop x86 processors, hence they
don't act like it.
More specifically, Atom support in GCC was only officially added in
4.5.0, which DJGPP doesn't have. By default DJGPP (still) uses -
mtune=3Dpentium (aka, i586), which maybe isn't that ideal. However,
having said that, I'd be extremely surprised if -mtune=3Di486 did much
of anything, if at all, esp. for your Atom. Seems GCC never cared too
too much about 486 (alignment only?) and certainly cares less nowadays
even.
If you really wanted, I guess? you could compile on Linux
(distrowatch.com says Fedora yes, Ubuntu only 4.4.4) with GCC 4.5.1
(or whatever) -mtune=3Datom and use http://agner.org/optimize/#objconv
to convert it to COFF and then link it with DJGPP, if you think the
new optimizations might help (doubt it but who knows).
Another solution (horrible, I admit) would be to use handcode some SSE
bullcrap, but that's usually more pain than it's worth (and hey, I
like assembly!). We just can't program new computers effectively like
they are the old ones we're used to.
What exact versions are you using? GCC 4.4.4? DJGPP 2.0[34]? FreeDOS
kernel 203[6789]? CWSDPMI r[567]? It all might make a difference. Of
course, posting code would explain more too, but again, I don't have
any similar (netbook) hardware to test for you.
- Raw text -