On Tue, Jan 8, 2019 at 3:01 PM dwight via cctalk
wrote:
> To Tell you the truth, I can't think of anything other than speed of
> calculating that should be done in floating point. The speed is because
> we've determined to waste silicon for floating point when we should really
> be using combined
PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Microcode, which is a no-go for modern designs
>> Few people (but most are right here) can recite PI to enough digits to
>> reach the level of inaccuracy. And those who believe that PI is exactly
>> 22/7 are unaffected
On Sun, Jan 6, 2019 at 1:00 PM Fred Cisin via cctalk
wrote:
> Few people (but most are right here) can recite PI to enough digits to
> reach the level of inaccuracy. And those who believe that PI is exactly
> 22/7 are unaffected by FDIV. (YES, some schools do still teach that!)
>
Really? I
Few people (but most are right here) can recite PI to enough digits to
reach the level of inaccuracy. And those who believe that PI is exactly
22/7 are unaffected by FDIV. (YES, some schools do still teach that!)
On Mon, 7 Jan 2019, Johnny Eriksson via cctalk wrote:
Why remember the digits,
> On Jan 7, 2019, at 3:20 AM, Johnny Eriksson via cctalk
> wrote:
>
>> Few people (but most are right here) can recite PI to enough digits to
>> reach the level of inaccuracy. And those who believe that PI is exactly
>> 22/7 are unaffected by FDIV. (YES, some schools do still teach that
> Few people (but most are right here) can recite PI to enough digits to
> reach the level of inaccuracy. And those who believe that PI is exactly
> 22/7 are unaffected by FDIV. (YES, some schools do still teach that!)
Why remember the digits, when a small program can provide them?
+0un q
Pentiums and it was a real hassle to have to field all those beefs from
customers whose EXPENSIVE processors couldn't divide accurately.
no
It was a real hassle to have to field all those beefs from customers who
had a PERCEPTION that their expensive processors Wouldn't divide
accurately.
Th
On Sun, 2019-01-06 at 11:08 -0800, Josh Dersch wrote:
> 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.
Memory is like that. The FDIV bug didn't go away because it was
announced, the chips stayed on desktops and our diagnostic sof
On 1/6/19 11:59 AM, Jeffrey S. Worley via cctalk wrote:
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 m
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 ori
What defines a 'modern processor'. The term is pretty slippery.
The Crusoe used microcode to emulate x86 and could therefore emulate
any processor architecture Transmeta wanted.
Crusoe was a pioneer in the low power market, the processor dynamically
clocked itself in very small steps depending o
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
On Fri, Jan 4, 2019 at 8:08 AM dwight via cctalk
wrote:
> May ability to understand these papers is somewhat limited. If I
> understand correctly the following.
> Most divide routines that I've seen allow the remainder to be 1,0,-1
> relative to the normal remainder. The answer will converge as t
.
At least that is my understanding. It is to early in the morning for me.
Dwight
From: Eric Smith
Sent: Thursday, January 3, 2019 11:55 PM
To: dwight; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Microcode, which is a no-go for modern designs
And th
And the original analysis paper, "It Takes Six Ones to Reach a Flaw":
http://www.acsel-lab.com/arithmetic/arith12/papers/ARITH12_Coe.pdf
Also
http://www-math.mit.edu/~edelman/homepage/papers/pentiumbug.pdf
On Wed, Jan 2, 2019 at 9:12 PM dwight via cctalk
wrote:
> I believe that is the one. Intel tried to say it wasn't an issue until it
> was shown that the error was significant when using floating point numbers
> near integer values. I suspect that the fellow that forgot to include the
> mask file
wight
From: Eric Smith
Sent: Wednesday, January 2, 2019 3:42 PM
To: dwight; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Microcode, which is a no-go for modern designs
On Wed, Jan 2, 2019 at 4:12 PM dwight via cctalk
mailto:cctalk@classiccmp.org>> wrote:
I thoug
On Wed, Jan 2, 2019 at 4:12 PM dwight via cctalk
wrote:
> I thought I'd note that the divide problem couldn't have been patched
> with a micro code patch.
If you're talking about the Pentium FDIV bug, present on the early 80501
chips (60 and 66 MHz) and 80502 chips (75, 90, and 100 MHz), they
Microcode, which is a no-go for modern designs
On Wed, Jan 02, 2019 at 02:37:44PM -0500, Paul Koning via cctalk wrote:
>
>
> > On Jan 2, 2019, at 2:31 PM, Chuck Guzis via cctalk
> > wrote:
> >
> > On 1/2/19 10:44 AM, Guy Sotomayor Jr wrote:
> >
> &
On Wed, Jan 02, 2019 at 02:37:44PM -0500, Paul Koning via cctalk wrote:
>
>
> > On Jan 2, 2019, at 2:31 PM, Chuck Guzis via cctalk
> > wrote:
> >
> > On 1/2/19 10:44 AM, Guy Sotomayor Jr wrote:
> >
> >> Also, recall that there are different forms of micro-code: horizontal
> >> and vertical.
> On Jan 2, 2019, at 2:31 PM, Chuck Guzis via cctalk
> wrote:
>
> On 1/2/19 10:44 AM, Guy Sotomayor Jr wrote:
>
>> Also, recall that there are different forms of micro-code: horizontal
>> and vertical. I think that IBM (in the S/360, S/370, S/390, z/Series)
>> uses the term micro-code for h
On 1/2/19 10:44 AM, Guy Sotomayor Jr wrote:
> Also, recall that there are different forms of micro-code: horizontal
> and vertical. I think that IBM (in the S/360, S/370, S/390, z/Series)
> uses the term micro-code for horizontal micro-code and millicode
> for vertical microcode.
On the CDC STAR
> On Jan 2, 2019, at 10:22 AM, Chuck Guzis via cctalk
> wrote:
>
> On 1/2/19 8:02 AM, Jon Elson via cctalk wrote:
>
>> Random logic instruction decode was a REAL issue in about 1960 - 1965,
>> when computers were built with discrete transistors. The IBM 7092, for
>> instance, had 55,000 tra
On 1/2/19 8:02 AM, Jon Elson via cctalk wrote:
> Random logic instruction decode was a REAL issue in about 1960 - 1965,
> when computers were built with discrete transistors. The IBM 7092, for
> instance, had 55,000 transistors on 11,000 circuit boards. I don't know
> how much of that was instru
On 01/02/2019 02:31 AM, Paul Birkel via cctalk wrote:
I'm curious as to why you make this claim that microcode is no-go in "modern"
designs. Could you please elaborate on this point? I don't see why the alternative
random control logic would be a better proposition.
Random logic instructi
.
>
>unfortunately, the 68K is very complex to be designed, and the first
>68020 used microcode, which is a no-go for modern designs.
>
>...
I'm curious as to why you make this claim that microcode is no-go in "modern"
designs. Could you please elaborate on this poi
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