michael3@garfield.UUCP (Mike Rendell) (08/15/85)
[] I am wondering why the Amiga uses the 68000 chip instead of the 68010? The 68010 has been out for quiet a while (about a year?) so it was around when the Amiga was being devoloped. Also, would it be possible to upgrade it to the 68010 (or maybe the 68020)? Mike Rendell michael3@garfield
csc@watmath.UUCP (Jan Gray) (08/26/85)
In article <3429@garfield.UUCP> michael3@garfield.UUCP (Mike Rendell) writes: >[] > > I am wondering why the Amiga uses the 68000 chip instead of the 68010? >The 68010 has been out for quiet a while (about a year?) so it was around >when the Amiga was being devoloped. Also, would it be possible to upgrade >it to the 68010 (or maybe the 68020)? > > > Mike Rendell > michael3@garfield Unless you need the ability to complete a page-faulted instruction you don't need a 68010. The 68010 also gets you "loop mode" (although I seem to remember unrolled loops are faster), a movable interrupt vector base, and a few other things, but 68010s are probably a bit more expensive than 68000s. The 68010 is pin compatible with the 68000. The 68020 on the other hand would be quite an improvement, but I doubt it would sync well with the Amiga interleave-DMA-with-instruction scheme, and it is of course not pin compatible. Jan Gray
kurt@fluke.UUCP (Kurt Guntheroth) (08/28/85)
The amiga uses the 68000 chip exactly because it is less expensive and the amiga does not require the 68010 extra capabilities of instruction restart. The 68000 and 68010 are directly compatible and if you want to speed everything up about 7-8%, you can just drop in a 68010 (assuming the 68000 is in a socket of course). -- Kurt Guntheroth John Fluke Mfg. Co., Inc. {uw-beaver,decvax!microsof,ucbvax!lbl-csam,allegra,ssc-vax}!fluke!kurt
dal@tikal.UUCP (Don Ledford) (08/28/85)
------ In article <916@vax2.fluke.UUCP> kurt@fluke.UUCP (Kurt Guntheroth) writes: >The amiga uses the 68000 chip exactly because it is less expensive and the >amiga does not require the 68010 extra capabilities of instruction restart. >The 68000 and 68010 are directly compatible and if you want to speed >everything up about 7-8%, you can just drop in a 68010 (assuming the 68000 >is in a socket of course). >-- I'm a software type and don't have access to the amiga schematics, but I would caution against replacing the 68000 chip with a 68010 until you know for sure it doesn't effect the shared access to the video RAM. It may be that access is arbitrated by monitoring the instruction fetch activity of the CPU (during fetch the DMA has a free shot at the video RAM). The 68010 doesn't need to perform fetches for certain types of code loops (hence the speed improvement); this may cause unacceptable delays for the video circuitry. Speculation only. Don Ledford
granvold@tymix.UUCP (Tom Granvold) (08/29/85)
- Yes you can replace a 68000 with a 68010 in an Amiga, Atari ST, MAC or any other machine that uses the 68000. The two chips are pin compatable. There are two advanges that I know of for doing this. First, the 68010 can handle page faults where the 68000 cannot. Second, the 68010 can internally hold short loops, 3 or 4 instructions, and therefore execute them faster that the 68000 can. No, putting a 68010 in any of these machines will not probably work. The reason is that the on some execptions, Motorola's name for interrupts, the 68010 saves more information on the stack than the 68000 does. This means that the OS will most likely need a couple of small changes. This is no problem if one knows the OS and has the source. I would not count on Commodore, Apple or Atari to do it for us. So to repleat, it will probably not work to replace the 68000 with a 68010 in an Amiga or other 68000 system. If someone in the S.F. bay area would like to try an experiment, I have a 68010 chip that we can us. If you have an Amiga, Atari ST or MAC and are willing to open it up to change the chip, I'd love to see if it works. Of course I can afford to make this offer since it won't be my machine being messed with :-). I don't have any of these machines yet. I am still debating over whether to get an ST and save money or spend more and get the Amiga. Tom Granvold Tymnet ucbvax!oliveb!tymix!granvold