Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!udel!mmdf
From: Dennis_Grant@cmr001.bitnet
Newsgroups: comp.sys.amiga.programmer
Subject: NorthC and BYTE sieve demo
Message-ID: <45620@nigel.ee.udel.edu>
Date: 23 Feb 91 23:57:54 GMT
Sender: mmdf@ee.udel.edu
Lines: 37


     I needed a first program for my new copy of NorthC, and I happened to
have an old BYTE magazine lying around, the issue where they introduced
their new benchmark suite. Inside was the source code for the sieve
program (the one that finds prime numbers). I typed it in, less the 2 lines
that dealt with getting system time values (I'd save those for later) and
ran the program.

      For those who may not be familliar with the program, it finds all the
prime numbers up to 16000 or so, 100 times over. In the version in the
magazine, it printed out each prime as it was found, so you wound up with a
LONG list of about 1600000 numbers. On a PC-XT, it (supposedly) took about
250 seconds.

     So anyway, off it goes, printing numbers. 5 minutes go by, and I start
to get suspicious. So I rebooted the machine, checked my code vs the code
in the magazine (it was right), and added a printf to print out what loop
it was on. I ran this one, and went to bed. (It was 03:00)

     I got up at 10:30, turned on the monitor, and lo! It hadn't finished.
I waited for the numbers to wrap over so I could see how far it got, and
I found it was on loop 57. The machine got the 3 finger salute.

     I edited the source code, got rid of the printf("%d\n",prime);
statement inside the main loop, and reran it. Bingo! One loop each second.
(More or less) for a final score of about 100 or so. As expected.

     My conclusion: The printf was taking a LOT of time to execute.

     My question: Is this normal? Could a lowly XT really crank out 1600000
printfs faster than my Amiga, or is this a quirk of NorthC? (or did BYTE
delete those printfs too?) Any ideas?

-------------------------------------------------------------------------------
  Dennis Grant   3rd year CS student at Le College Militaire Royal de St-Jean
  DETUD595@CMR001.BITNET
  How much do I love thee? My accumulator overflows!