Mail Archives: djgpp/1998/09/08/09:44:56
Tal Lavi <ranla AT post DOT tau DOT ac DOT il> wrote:
> Tal Lavi wrote:
> >
> > A little highly optimized graphics aplication that run prety good on
> > TP7 using mode 0x13, is experiencing a MAJOR slowdown using VBE2.0 in
> > linear frame buffer mode, using two pages for ultra fast flipping.
> > I am probably accessing the LFB memory wrong(_farsetsel, and
> > _farnspoke*). I tried using the inline assembler, but I can't seem to
> > get it working.
>
> The profiler says that __dpmi_int was used allot, but i swear I haven't
> put even one in the actual run-time part!
But perhaps you are calling DOS or BIOS though libc.
> Alas, the profiler won't tell
> me from which function was the _dpmi_int(s) was called.
> Does anyone knows whether getch()
Don't use getch() in a place where speed is a critical factor! put it outside
any fast loop, check the keyboard ones per frame.
> or _far* calls __dpmi_int?
Eli already told you that farptr stuff are macros expanded to few assembler
instructions.
> And yet another thing, the div
What div?
> function in stdlib.h takes allot of
> computation time too! I only do two division with it per loop cicle!!!
> what's wrong with that picture?!?
What kind of divisions? are you using long long?
> div is a integer based division, right? then why does it take over 40%
> of the computation time?
You are doing something wrong, post the code.
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