Path: utzoo!attcan!uunet!crdgw1!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!swrinde!ucsd!ucbvax!galileo.berkeley.edu!jbuck From: jbuck@galileo.berkeley.edu (Joe Buck) Newsgroups: comp.arch Subject: Re: The CPU with 3 brains Message-ID: <39409@ucbvax.BERKELEY.EDU> Date: 6 Nov 90 19:22:55 GMT References: <42737@mips.mips.COM> <1990Nov4.014901.23819@zoo.toronto.edu> <2841@crdos1.crd.ge.COM> Sender: usenet@ucbvax.BERKELEY.EDU Reply-To: jbuck@galileo.berkeley.edu (Joe Buck) Lines: 24 In article <2841@crdos1.crd.ge.COM>, davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) writes: > In article pcg@cs.aber.ac.uk (Piercarlo Grandi) writes: > > | Except for oddities like the 860 and 960, isn't the 486 still designed > | to be almost binary compatible with the 8008? Sigh! > > As far as I know the 80486 and 8008 are completely compatible at the > level of the first two digits of the part number. The instruction set is > 100% diferent, so the only binary compatibility is that they both will > read ones and zeros. Well, they are pretty much compatible at the assembly language level. When the 8086 was first announced, one of Intel's big claims was that, although the binary encoding had changed, you could reassemble your 8080 programs and they would run on the 8086. Since the 8080 is the 8008 plus some extra instructions, and since the 80486 supports 8086 instructions, it therefore follows that yes, you can run your 8008 assembly language programs on the 80486; however, you need a 8008 (or 8080) disassembler followed by an 80486 (or 8086) assembler to do it. So Piercarlo is essentially correct. -- Joe Buck jbuck@galileo.berkeley.edu {uunet,ucbvax}!galileo.berkeley.edu!jbuck