OpenEuphoria

Re: Scrolltext

• Posted by Robert Craig <rds at EMAIL.MSN.COM> Jan 20, 1999
• 478 views

Tor Bernhard Gausen writes:
> The depressing problem is that my routine is incredibly slow.
> I'm clearly doing something REALLY wrong, but what?

If you don't need smooth scrolling, you can use Euphoria's
scroll() library routine in any graphics or text mode. It's reasonably fast.
Here's a mode 18 example.

include graphics.e
if graphics_mode(18) then
end if

for i = 1 to 30 do
     printf(1, "%d:%s\n", {i, 'A' + rand(repeat(20, 60))})
end for

for i = 1 to 100 do
    scroll(1,1,30)   -- scroll lines 1..30 up one line
    position(30,1)
    printf(1, "%d:%s", {i, 'A' + rand(repeat(20, 60))})
end for

if graphics_mode(-1) then
end if

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.

Regards,
     Rob Craig
     Rapid Deployment Software
     http://members.aol.com/FilesEu/