Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lll-winken!uunet!cbmvax!daveh From: daveh@cbmvax.UUCP (Dave Haynie) Newsgroups: comp.sys.cbm Subject: Re: what is this chip(65C802) Message-ID: <6528@cbmvax.UUCP> Date: 6 Apr 89 18:15:38 GMT References: <2310@maccs.McMaster.CA> Organization: Commodore Technology, West Chester, PA Lines: 51 in article <2310@maccs.McMaster.CA>, cs3b3aj@maccs.McMaster.CA (Stephen M. Dunn) says: > Summary: 6502 Family has some _serious_ design problems >>An 8080sux takes 4 clock cycles to read a byte from the bus. The 6502, >>65c02, etc. take 1 clock cycle. Thus a 8 mhz 6502 would be the >>equivalent of a 32mhz 8086-based machine. Considering that 80x6-based > The problem with your argument is that you assume that everything on an > 8086 takes four times as long as on a 6502. There really isn't much of a problem with this argument. Look again, we were talking about memory system requirements, nothing else. From the point of view of the memory system, this isn't far off. However, I have no doubt that a 32MHz 8086 machine (assuming one could build such a critter) would easily outpace an 8MHz 6502 type machine. Because of the fact that memory access isn't everything -- what can be accomplished in single instructions, and how much can be done without touching main memory (eg, via registers or cache) also have to get factored into this. > But back to the 6502 family; it's a seriously flawed processor ... It wasn't all that bad for it's time. It was much easier to design a 6502 system than an 8080A or Z-80 system, and for most of the things a micro computer had to do back then, it was faster than 8080 or Z-80 systems that were available at the time (the early Apple II and PETs were noticably faster than my first micro, the Z-80 based Exidy Sorcerer) for the same marketplace (Z-80 business systems were built than outpaced most 6502 and even many of the later 8088 systems, but they weren't cheap). You might also want to re-read the stuff I deleted. Virtually every complaint about the 6502 vs. the 8088 can be applied to the argument of 80x86 vs 680x0. I just found that kind of interesting. > One thing we have to watch out for here is comparing apples (with a small a) > to oranges - the 6502 and 8080 families were designed in the early seventies, > and they're 8-bit chips, whereas the 8086 family came out in the late > seventies and are 16 bits (or more). The 6502 and the 8086 aren't really > comparable (as my example a couple of pages ago, on 16-bit integer > division, was meant to show). The 8086 and 8088, internally, are pretty much 8 bit chips that can at times manipulate 16 bit data. Much in the same way that a 68000 in mostly 16 bits internally, but does 32 bit operations (as I recall, there are 3 sixteen bit ALUs in the 68000, two of which team up to do a 32 bit operation). > ! Stephen M. Dunn, cs3b3aj@maccs.McMaster.CA ! DISCLAIMER: ! -- Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy Amiga -- It's not just a job, it's an obsession