Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!agate!ucbvax!ucsd!rutgers!att!mcdchg!mcdphx!xroads!skipper From: skipper@xroads.UUCP (Skipper Smith) Newsgroups: comp.sys.amiga Subject: Re: UNIX vs. Amiga speeds Summary: That minor change Message-ID: <626@xroads.UUCP> Date: 15 Apr 89 00:42:21 GMT References: <0912.AA0912@julie> <6490@cbmvax.UUCP> <22977@shemp.CS.UCLA.EDU> Distribution: na Organization: Crossroads, Phoenix, Az Lines: 46 In article <22977@shemp.CS.UCLA.EDU>, michael@maui.cs.ucla.edu (michael gersten) writes: > In article <6490@cbmvax.UUCP> daveh@cbmvax.UUCP (Dave Haynie) writes: > :In article <0912.AA0912@julie>, mcr@julie.UUCP (Michael Richardson) says: > : > :> Out of curiosity, why weren't the 500 and 2000 just released > :> with 68010s? > : > :No software change would be necessary. > > Wrong. The 68010 has one instruction privleged that was not privledged > on the 68000. This kills early versions of Lattice's math library, > and some games. > > Michael The only instruction that was changed was the MOVE.W SR, which copies the entire status register into some effective address. Any program which does not make use of that instruction (and only while running in USER mode) will work perfectly- as long as it is user code. Because of the different sized stack frames (which some people like to pick information off of) that are created during exception processing, some supervisor code (read OS) would have to be modified, but it is (depending on how gung ho people are) fairly trivial. By adding the 68010, the Amiga would have gained the capabilities to use virtual memory and create virtual machines. For those who don't know what a virtual machine is, suffice to say that the problem (?) of running UNIX under AmigaDOS could have fairly easily (as a guess only, I am no expert on this topic) circumvented. Oh yes, it is the MOVE.W SR, that causes that problem. I personally could care less about running UNIX and AmigaDOS at the same time since I don't have 5-9 Mb of RAM to make it work reasonably well, but I would sure like to be able to use the unused portions of a 380 Mb hard drive (I got a good deal, ok?) for virtual memory until I can get that extra RAM. Skipper Smith Motorola Technical Training Tempe, AZ (Please send all comments/flames/etc... directly to me, as I travel a great deal and just might skip over it while trying to read through the plethora of net.junk that accumulates over a couple of weeks) -- \ / C r o s s r o a d s C o m m u n i c a t i o n s /\ (602) 941-2005 300|1200 Baud 24 hrs/day / \ hplabs!hp-sdd!crash!xroads!skipper