[CCTECH] Interesting tidbit on 6502

From: Richard Erlacher <edick_at_idcomm.com>
Date: Fri Jun 7 13:47:37 2002

... regarding that Pentium FDIV bug ... my understanding from the guys on the
inside is that they knew about the bug for nearly a year before the buggy
parts were released. The management made the decision that since many of
their customers didn't need the FDIV instruction, they could sucessfully build
hardware around it with no ill effects. The home PC market, after all, was
then still an insignificant part of their market. They knew well in advance
that they'd be replacing the "buggy" parts, but had to start getting some of
their NRE back in order to avoid the IRE of top management.

Dick

----- Original Message -----
From: "Ben Franchuk" <bfranchuk_at_jetnet.ab.ca>
To: <cctalk_at_classiccmp.org>
Sent: Friday, June 07, 2002 9:31 AM
Subject: Re: [CCTECH] Interesting tidbit on 6502


> "J.C. Wren" wrote:
> >
> > Why don't you learn that you don't always know what you're talking
about?
> >
> > Indeed, the first step level of the 6800 had an undocumented
opcode that
> > results in 3 particular transistors turning on that connected Vcc to GND.
> > The damage caused by these three transistors shorting damaged the silicon
in
> > the immediate area, rendering the CPU useless.
> >
> > But since the shop I worked for only flamed out 2 Sphere-II 6800
CPUs
> > before the Motorola FAE defined the problem and gave us new parts, it
> > probably didn't really happen, since you said it's fiction.
>
> Since this was a early and rare version of the 6800 and most of my
> information
> is second hand stuff (general computer books vs data sheets )
> information
> like this is useful trivia. Even modern chips can have hard to find
> bugs,
> like the pentium division bug.
>
>
> --
> Ben Franchuk - Dawn * 12/24 bit cpu *
> www.jetnet.ab.ca/users/bfranchuk/index.html
>
Received on Fri Jun 07 2002 - 13:47:37 BST