Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!pacbell.com!tandem!zorch!amiga0!mykes From: mykes@amiga0.SF-Bay.ORG (Mike Schwartz) Newsgroups: comp.sys.amiga.advocacy Subject: Re: Blitter vs. 040 (was: Computer Architecture question Message-ID: Date: 17 May 91 09:14:08 GMT References: <1991May9.070349.15151@neon.Stanford.EDU> <3496.tnews@templar.actrix.gen.nz> <1991May10.180908.29565@convex.com> <1991May13.004217.23406@techbook.com> Organization: Amiga makes it possible Lines: 50 In article <1991May13.004217.23406@techbook.com> waynekn@techbook.com (Wayne Knapp) writes: >swarren@convex.com (Steve Warren) writes: > > >>In the A3000, the 68030 can update display memory faster than the blitter can. >>This does not mean that there is no advantage to using the blitter (and the >>blitter does not loose by *that* much). The fact is, if the blitter is used >>to manage the display and the '030 is able to stay out of display memory, then >>the '030 will be able to "multiprocess" in parallel with the blitter. So if >>you have calculations that need to be performed then, it is advantageous to use >>the blitter to offload graphic manipulations from the CPU. > > >Two three things wrong with this. > Oops, I forgot to mention something... > 3) Everyone is always shouting about how the CPU and Blitter can run at the > same time. But in real life, it rarely happens. There are several > reasons for this. > a) The blitter requires CPU to adjust it's registers between bitplanes. > b) Most blits are short in time, too short for the operations system to > allow the CPU much chance to run. > c) It is very hard and complex to pull off. > Now, it can be done, and I'm sure someone has some has. But not as a > general rule, and certainly not something you get for free. > The blitter is used for a LOT more than just simple animation on the AMiga. It is used to do quite large operations all the time, especially when dealing with windows and the rest of the interface. The CPU can't do proportional fonts as fast as the blitter, or refresh a window, or do layers, etc. This is the most obvious use of offloading graphics operations from the CPU to the blitter done by the Amiga. > Wayne Knapp > Consultanting Assoc. > Hash Enterprises > >-- >waynekn@techbook.COM ...!{tektronix!nosun,uunet}techbook!waynekn >Public Access UNIX at (503) 644-8135 (1200/2400) Voice: +1 503 646-8257 >Public Access User --- Not affiliated with TECHbooks -- **************************************************** * I want games that look like Shadow of the Beast * * but play like Leisure Suit Larry. * ****************************************************