On Sun, Jan 6, 2019 at 10:59 AM Jeffrey S. Worley via cctalk < cctalk@classiccmp.org> wrote:
> On Sat, 2019-01-05 at 12:00 -0600, cctalk-requ...@classiccmp.org wrote: > > Re: Microcode, which is a no-go for modern designs > > I was a tech in the 90's when the original Pentium FDIV bug was > storming. The issue was confined to the integrated floating point > portion of the processor and was therefore rarely an issue as the vast > majority of software did not use the mathco portion of the chip. Only > a handful of applications and relative handful of users were affected. > This became Intel's position on the matter and they hoped the issue > would just die down to those handful whom they would provide new chips. > > The issue did not die down and the bad press forced the decision to > replace ALL pentiums affected. Only a relative few were actually > replaced in the home and small business arena. A software patch was a > common solution to the problem. It masssaged input to the FDIV > instruction to produce a corrected result and worked pretty well as I > recall. > > At the time of the storm, the Pentium was still pretty new and very > expensive. Most folks were getting along with AMD k5 and k6 > processors. I WAS. I went from k6 to Celeron. > That's a good trick, given that the K5 came out in 1996 and the K6 in 1997, the FDIV issue blew up in late 1994. - Josh > > Best > > Jeff > >
