Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!sdd.hp.com!spool.mu.edu!cs.umn.edu!kksys!orbit!pnet51!chucks
From: chucks@pnet51.orb.mn.org (Erik Funkenbusch)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Blitter vs. 040 (was: Computer Architecture question
Message-ID: <4954@orbit.cts.com>
Date: 20 May 91 03:48:55 GMT
Article-I.D.: orbit.4954
Sender: root@orbit.cts.com
Organization: People-Net [pnet51], Minneapolis, MN.
Lines: 31

sschaem@starnet.uucp (Stephan Schaem) writes:
>
>
> This is crazy! 'twice faster has a 68000' do people know why?
> Because CBM took timing from a loop with instruction fect...
> Again the Blitter is like a 68020, and do its internal calculation
> WHILE accesing the bus!
> So you CANT squeze more out of the bus, and if you can go faster with a
> 680x0 than the blitter the bus usage is the 'same' (With cache on cpu
> to do logical op on data while accesing the bus).
> The blitter curent problem in a A3000, its not 32bit etc...


let me say this loudly!

THERE IS LITTLE REASON FOR THE CPU TO ACCESS THE SAME BUS AS THE BLITTER!

there, most everything the cpu does (executing programs) is done in fast
memory.  fast memory is on a seperate bus than chip memory. therefore having 2
busses with 2 seperate processors on them means there should be little bus
contention.  the only time the cpu NEEDS to access chip memory is to program
the blitter, and that's only for a few cycles.  

.--------------------------------------------------------------------------.
| UUCP: {amdahl!tcnet, crash}!orbit!pnet51!chucks | "I know he's come back |
| ARPA: crash!orbit!pnet51!chucks@nosc.mil        | from the dead, but do  |
| INET: chucks@pnet51.orb.mn.org                  | you really think he's  |
|-------------------------------------------------| moved back in?"        |
| Amiga programmer at large, employment options   | Lou Diamond Philips in |
| welcome, inquire within.                        | "The First Power".     |
`--------------------------------------------------------------------------'