ai065@cleveland.Freenet.Edu (Thomas Hill) (06/29/91)
I've kept this file around for a while as it has some very good solid information on the Amiga blitter (and Atari blitter) in it. Because there has been recent talk of the Atari blitter being somehow faster and/or better, I'm reposting this here in comp.sys.amiga.advocacy. Article #458 (538 is last): From: daveh@cbmvax.commodore.com (Dave Haynie) >Newsgroups: comp.sys.amiga.emulations Subject: Re: Amiga Emulator for the ST. Sounds Bogus. Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Date: Tue Mar 12 17:58:07 1991 In article <1991Mar12.022622.25956@mintaka.lcs.mit.edu> rjc@geech.ai.mit.edu (Ray Cromwell) writes: >> What is this Amiga emulator your talking about? Sounds like vaporware > Without wishing to start a computer war, a friend of mine has an >Amiga emulator for his Atar 1040ST. It i commercial package, thats been >around since 1987, released by Metacomco. This is undoubtedly bogus. First of all, there wasn't much Metacomco code in the original AmigaOS anyway; what was there was simply part of the DOS subsystem. They might try to sell you a version of Tripos for the ST, but it wouldn't be an Amiga emulator. >The manual states that it runs around 7 times faster than a real amiga, disk >drive i/o is much faster, Again, not possible. In pure CPU loops, the original ST would go a tad faster than an A1000, may 11% maximum (the difference between 8MHz and 7.16MHz). The PC inspired floppy interface is slower on the ST. >but the whole thing slows down when it comes to emulating the specialised >chips (some of them not all). To run the Amiga OS, you are by definition using most of the features of the Amiga custom chips. >It requires the atari blitter to be installed, which runs approx 40 times faster >than the amigas blitter which somewhat Was the Atari blitter even available in '87? In any case, this is pure ST propaganda -- Stalin would have been proud. The ST blitter is roughly 1/4 to 1/2 the speed of the Amiga blitter doing operations the ST blitter supports. Amiga's blitter runs at double bus speed, 14.3 MHz, when cranked up. If you have fast RAM, the CPU and blitter can both be going at once. The ST blitter shares the bus with the 68000; it runs the same memory cycle as the 68000, and you can have only one on the bus at any given time. Additionally, the ST blitter supports 16 operations between two operands to one destination. The Amiga blitter supports 256 operations between three operands to one destination and additional tricks, like line draw. What it does well, it does faster than a 68020 at 14.3MHz. Most of the copper tricks cannot be emulated on the ST at all. >Can anyone confirm or deny that this Metacomco product really >exists? Either someone is exaggerating ALOT, or Metacomco is >falsly advertising, because I don't believe this. This is the first I have heard of any such product. I would consider that very strange for any product of any significance to the Amiga market that's supposedly been around since '87. My guess is that this is totally bogus. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "What works for me might work for you" -Jimmy Buffett [END] Tom
mykes@amiga0.SF-Bay.ORG (Mike Schwartz) (06/30/91)
In article <30524@know.pws.bull.com> ai065@cleveland.Freenet.Edu (Thomas Hill) writes: >In article <1991Mar12.022622.25956@mintaka.lcs.mit.edu> rjc@geech.ai.mit.edu (Ray Cromwell) writes: > >>The manual states that it runs around 7 times faster than a real amiga, disk >>drive i/o is much faster, > >Again, not possible. In pure CPU loops, the original ST would go a tad faster >than an A1000, may 11% maximum (the difference between 8MHz and 7.16MHz). The >PC inspired floppy interface is slower on the ST. > Actually, all instructions on the ST must end in a modulo 4 # of clock cycles. Anything that takes 6 cycles ends up 8 on the ST. -- **************************************************** * I want games that look like Shadow of the Beast * * but play like Leisure Suit Larry. * ****************************************************
peter@Sugar.NeoSoft.com (Peter da Silva) (06/30/91)
In article <30524@know.pws.bull.com> ai065@cleveland.Freenet.Edu (Thomas Hill) writes: > I've kept this file around for a while as it has some very good solid > information on the Amiga blitter (and Atari blitter) in it. What makes you think we care? Your flame war on c.s.a.st was funny for a day or so (and I took my shots) but the Atari is a lost cause. Forget it. Respect followups (and you folks on c.s.a.st might direct your own followups the same place). -- Peter da Silva. `-_-' <peter@sugar.neosoft.com>. 'U` "Have you hugged your wolf today?"