Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!rutgers!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Questions about QBlit(), etc.
Message-ID: <16665@cbmvax.commodore.com>
Date: 19 Dec 90 08:24:50 GMT
References: <1990Dec17.075228.15068@watdragon.waterloo.edu>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 28

In article <1990Dec17.075228.15068@watdragon.waterloo.edu> ccplumb@spurge.uwaterloo.ca (Colin Plumb) writes:
>Also, how much system overhead is there on Amy?  I have a couple of routines
>I'm timing, one of which should take (by the 68000 manual) 105932 cycles per
>call (there are not data dependencies), and I call it 50 times, so it should
>take only slightly more than 44.4 vblank intervals.  I observed 51, 52, and
>52, 15% over.
>
>Another is 10% over its time, with 51 calls and an average of 190174 (slight
>data dependency) cycles each.  It should take 81.3 vblanks, and I get 90.
>
>The environment is an NTSC Amiga 1000, 4 MB fast memory, 2 floppies, a
>floppy in each, no mouse or keyboard activity, vanilla WB 1.3 with Manx
>tools in rad:, no daemons, pipe:, ram:, rad: and newcon: mounted.
>
>Where is the time going?  Do vblank interrupts (gameport.device,
>timer.device) and a bit of intuiticks activity take that long?

	Don't forget trackdisk checking disk insertion/removal every .5sec
if there's a disk in the drive, 2.5s without a disk.

	10% is quite possible.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
The compiler runs
Like a swift-flowing river
I wait in silence.  (From "The Zen of Programming")  ;-)