OpenEuphoria

Re: Thanx

• Posted by The AfterBeat <afterbeat at GEOCITIES.COM> Jan 23, 1999
• 606 views

You're welcome! :)

When I commented out the line that waited for the vertical retrace, it
still went smooth for me, but that's probably because I got a pretty fast
cpu (PII-400MHz)..  Heh.

Oh yeah, and if I ever find the location for the characters 128 thru 255,
I'll tell ya.  *Goes and downloads ASMEdit, hoping he can find it again*

   The AfterBeat

Tor Bernhard Gausen wrote:

> I just want to thank everyone for responding to my inquiry
> about my silly scrolltext routine 
>
> A few comments though:
>
> Robert Craig says:
> > As for your smooth scrolling program, it spends over 95%
> > of it's time doing mem_copy() of 64000 bytes. Euphoria's
> > mem_copy() calls C's memcpy(). I don't think you could
> > run your program more than about 1% faster in C. I believe
> > that writes to screen memory are much slower than writes
> > to general DRAM addresses, because of the lack of caching.
>
> Then the memcpy() command is probably assembled, right?
> Does this mean it wouldn't even be much faster in pure
> machine code? I mean; copying 64000 bytes from one place
> to another should not be any challenge for a modern processor,
> even in high-level language, so is the caching problems simply an
> unavoidable hardware bottle-neck?
>
> Afterbeat says:
> > I tested out that program, and I found that it goes faster,
> > and the text doesn't shake, when you take out the
> > vertical retrace routine.
>
> Yes, but then it's not smooth at all !
> Afterbeat also helped me find the standard charset, thanx!
>
> Lucius L. Hilley III also answered some of my questions,
> but perhaps the most helpful and enlightening answer came
> from Jiri Babor:
>
> > In recent years I really had to use a wait_retrace routine
> > only when I was messing around with page switching.
> > Otherwise the 'modern' hardware does not seem to need it.
> > I ran your scroller and it was reasonably smooth at the
> > lowest speed setting after I commented out the line with
> > the wait_retrace call.
>
> Exactly. 'Reasonably smooth'.
>
> I have mentioned the Commodore 64 earlier. This is a machine
> people now-a-days use as a standardized symbol of old fashion,
> out classed, stone age computer technology.
>
> But among game and demo programmers on the 64 one rule was
> crystal clear: If it wasn't perfectly smooth, it wasn't worth watching.
>
> Those days, 'Reasonably smooth' was just not smooth enough... 
>
> > BTW, you should never rely on the hardware to dictate the
> > top speed. Everybody's machine will be ten times faster
> > in three years time.
>
> I'd say about 4 times faster, wanna bet ?  
>
> > maximum speed, even if you never get anywhere near it
> > with your present gear. In a decade or so software
> > archeologists will praise you for it...
>
> I guess you are right, but calling the time() function also
> steal raster. With the time delayer (even when set to zero
> delay, but still calling time(), it seems impossible to get
> anything smooth...
>
> ( Then Jiri guides me through some font problems, thanks again 
>
> > You also mentioned drawing lines, circles, etc. on virtual
> > screens. Have a look at my vgraph.e in the Archives.
> > It is pretty old and neglected, but it does lines, ellipses
> > and polygons reasonably fast.
>
> Just what I was looking for !
>
> Anyway, since I'm a natural quitter, I'm gonna give
> up the silly "smooth scrolling project" for now.
>
> I'm never gonna quit Euphoria, though...
>
> Tor Bernhard Gausen