On Mon, Dec 11, 2006 at 11:09:13AM -0200, Daniel van Ham Colchete wrote: >> You know what? I don't. > So test it yourself. You're making the claims, you're supposed to be proving them... > As I said, it is an example. Take floatpoint divisions. You have > plenty of ways of doing it: 387, MMX, SSE, 3dNow, etc... Here GCC have > to make a choice. No, you don't. MMX, SSE and 3Dnow! will all give you the wrong result (reduced precision). SSE2, on the other hand, has double precision floats, so you might have a choice there -- except that PostgreSQL doesn't really do a lot of floating-point anyhow. > And this is only one case. Usually, compiler optimizations are really > complex and the processor's timings counts a lot. You keep asserting this, with no good backing. > If you still can't imagine any case, you can read Intel's assembler > reference. You'll see that there are a lot of ways of doing a lot of > things. I've been programming x86 assembler for ten years or so... > Steinar, you should really test it. I won't read the PostgreSQL source > to point you were it could use SSE or SSE2 or whatever. And I won't > read glibc's code. Then you should stop making these sort of wild claims. > You don't need to belive in what I'm saying. You can read GCC docs, > Intel's assembler reference, AMD's docs about their processor and > about how diferent that arch is. I have. /* Steinar */ -- Homepage: http://www.sesse.net/
