Re: [Simh] Looking for a milestone

2016-10-18 Thread Paul Koning
> On Oct 17, 2016, at 8:42 PM, Nelson H. F. Beebe wrote: > > ... > Some current compilers, such as releases of gcc for the last several > years, use the GMP and MPFR multiple-precision arithmetic packages to > supply correct compile-time conversions. Presumably, the

Re: [Simh] Looking for a milestone

2016-10-17 Thread Leo Broukhis
On Mon, 17 Oct 2016 15:29:10 -0600, Kevin Handy wrote: How close are the simh emulators to the real hardware's floating point? How > exct is the emulation of FPU's? > Does simh emulate the real hardware close enough that you can use it to > analyze the original hardware

Re: [Simh] Looking for a milestone

2016-10-17 Thread Nelson H. F. Beebe
The discussions on this thread began with a question about the accuracy of binary->decimal->binary conversions. The key original references are recorded in http://www.math.utah.edu/pub/tex/bib/fparith.bib http://www.math.utah.edu/pub/tex/bib/fparith.html in entries

Re: [Simh] Looking for a milestone

2016-10-17 Thread Paul Koning
> On Oct 17, 2016, at 5:29 PM, Kevin Handy wrote: > > How close are the simh emulators to the real hardware's floating point? How > exct is the emulation of FPU's? > Does simh emulate the real hardware close enough that you can use it to > analyze the original hardware

Re: [Simh] Looking for a milestone

2016-10-17 Thread Kevin Handy
It varies from 16 bits to 256 bits. Go to the wikipedia.org article on "IEEE floating point" for an overview. On Mon, Oct 17, 2016 at 3:30 PM, Ray Jewhurst wrote: > Just out of curiosity how many bits does the IEEE standard require for > floating point? > > On Oct 17,

Re: [Simh] Looking for a milestone

2016-10-17 Thread Ray Jewhurst
Just out of curiosity how many bits does the IEEE standard require for floating point? On Oct 17, 2016 3:51 PM, "Leo Broukhis" wrote: > Dijkstra is above reproach; I try to compare the averages. > > Having eps^2 = eps is cute, but, given that the idea didn't spread to > other

Re: [Simh] Looking for a milestone

2016-10-17 Thread Kevin Handy
How close are the simh emulators to the real hardware's floating point? How exct is the emulation of FPU's? Does simh emulate the real hardware close enough that you can use it to analyze the original hardware floating point processors? (For those that actually had FPUs instead of doing it in

Re: [Simh] Looking for a milestone

2016-10-17 Thread Leo Broukhis
Dijkstra is above reproach; I try to compare the averages. Having eps^2 = eps is cute, but, given that the idea didn't spread to other pre-IEEE f.p. implementations nor to IEEE (it is possible to iteratively square a number x with 0 < abs(x) < 1 down to 0, given enough iterations, denormals or

Re: [Simh] Looking for a milestone

2016-10-17 Thread Timothe Litt
On 17-Oct-16 13:42, Clem Cole wrote: > > On Mon, Oct 17, 2016 at 12:35 PM, Paul Koning > wrote: > > That doesn't excuse sloppy work. > > > ​Agreed - and you will rarely see me defend Seymour. His systems > were fast, but they were

Re: [Simh] Looking for a milestone

2016-10-17 Thread Paul Koning
> On Oct 17, 2016, at 1:42 PM, Clem Cole wrote: > > > On Mon, Oct 17, 2016 at 12:35 PM, Paul Koning wrote: > That doesn't excuse sloppy work. > > ​Agreed - and you will rarely see me defend Seymour. His systems were fast, > but they were not

Re: [Simh] Looking for a milestone

2016-10-17 Thread Paul Koning
I think that the same answer applies to your narrower question, though I didn't see it mentioned specifically in the documents I've read. For example, the treatment of underflow and very small numbers in Electrologica was novel at the time; Knuth specifically refers to it in a footnote of

Re: [Simh] Looking for a milestone

2016-10-17 Thread Clem Cole
On Mon, Oct 17, 2016 at 12:35 PM, Paul Koning wrote: > That doesn't excuse sloppy work. ​Agreed - and you will rarely see me defend Seymour. His systems were fast, but they were not programmer friendly in any way IMO. Heck the man never had an assembler - he did not

Re: [Simh] Looking for a milestone

2016-10-17 Thread Leo Broukhis
Paul, My question is more narrow. It focuses specifically on the binary<->decimal transformation. It appears that while the f.p. instructions and the elementary functions were proved correct to the appropriate precision, there was not much care taken to ensure, for example, that "FLOAT_MAX",

Re: [Simh] Looking for a milestone

2016-10-17 Thread Paul Koning
> On Oct 17, 2016, at 12:30 PM, Clem Cole wrote: > > "Correct" is difficult check out: http://www.netlib.org/paranoia/paranoia.c > > This set of programs lead to the IEEE FP format work. And Paul is 100% > correct, Seymour was

Re: [Simh] Looking for a milestone

2016-10-17 Thread Paul Koning
> On Oct 14, 2016, at 7:22 PM, Leo Broukhis wrote: > > I wonder what is the historically first programming environment with native > binary floating point which had been proved/demonstrated to handle f.p. > binary<->decimal I/O conversions 100% correctly? > By 100% correctly