[comp.sys.atari.st] Turbo16

hyc@math.lsa.umich.edu (Howard Chu) (02/28/90)

Well, I finally have Turbo-16 installed in my ST. Now I'm really
cruising, as they say... I've only played with it for a few hours,
so I don't have thorough impressions of it just yet. The Alcyon
compiled dhrystone benchmark said 1300 dhrystones. I lost my list
of figures from other machines, so I have no idea how this compares
to other systems.

Things that don't work, or don't work right - I get all kinds of
glitches when the blitter is active. In lo-rez, the screen is perfect.
In hi-rez, glitches are pretty rare, though rubber-band boxes always
leave trash. In med-rez, rubber-band boxes leave trash, menus leave
trash, text is distorted or shifted, etc... Consider two bit-planes of
med-rez screen where on a character-by-character basis, a cell is drawn
some number of bytes right, or shifted some number of lines down. It looks
pretty funky. (White characters get split into green & red components, etc.)
Whole fields of screen memory get right-shifted a few columns, particularly
during scrolling operations. Intense mouse (interrupt?) activity really
drives things nuts, and can cause a lock-up in both hi and med rez.

Falcon doesn't seem to like the cache. About 5 seconds after I get off
the runway, the engine literally explodes, all by itself, and the entire
damage panel lights up in red. Every system on the plane is trashed, and
depending on how fast you were going, you crash into the ground a few seconds 
later. It's quite perturbing. It always marks you down as Colonel level,
no matter what you selected at the beginning.

Those were the only things that really bothered me. Airball didn't work,
but now that I think of it, that change happened when I got TOS 1.4
installed. Gauntlet II died trying to read its protection scheme. Tetris
worked, but I don't need to play an *accelerated* game of Tetris, thank you.
Vindicators worked, but it seemed a tad fast as well. Dungeon Master
works great, though it's a little disconcerting to have monsters attack
so quickly. (But it's kind of a kick to watch your lightning bolts and
fireballs zoom off twice as fast as they used to...) All-in-all, this
doesn't seem to be the smartest thing to get if all you wanna do is play
games on the ST.

A brief run-thru with QuickIndex 1.5 showed CPU-memory access was 135% of
normal, CPU operations were around 203% (Gee, *more* than twice as fast!
How is this possible??  }-) Ya better not blink when you go thru the BIOS
text tests, 'cause you'll probably miss 'em. (With TurboST active as well,
text literally flies right by. Wipe-on, Wipe-off, it's gone. Neat.  }-)
Pretty nice effect, overall. Since at this moment I'm still suffering from
pre-break school-crunch, I don't have enough time to delve further just
yet. But I expect to see wonderful things when I sit down to hacking RSN....

Oh, oddly enough, blitter behavior is slightly less erratic when Overscan
is active. (Works fine... The WordFlair demo looked very slick in that light,
a nice large screen doing GDOS-based output as fast as you'd expect of plain
text. Uniterm clips along real well too...) [Ok, ok, I admit, I was up late
last night playing with this stuff instead of studying for my exam.... It
was an easy exam tho!  }-)  ]

Ok, so, next time someone around here mentions "speeding up arc" or "fast
compression routines" I'm gonna say "$300 - get a Turbo16."  }-)
(Just kidding. The thing about going fast is ya always wanna go *faster*)


--
  -- Howard Chu @ University of Michigan