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raw March 18 Minutes



IEEE 754r Meeting minutes March 17, 2004
Sun, Santa Clara

Attendees (partial list):       Affiliation
Dan Zuras       Self
David Hough     Sun
Eric Schwartz   IBM (phone)
Alex Liu        Sun
Joe Darcy       Sun (host)
Jim Thomas      HP
Mike Cowlishaw  IBM (phone)
Ivan Godard     OOTBC
Jeff Kidder     Intel (minute taker)
Fred Tydeman Self
Dick Delp
David Bindel UC Berkeley
Jason Riedy UCB
Peter Markstein
Leonard Tsai
W Kahan UC Berkeley

Note taker: Jeff Kidder

Called to order 1:15
Agenda:
Would like to extend schedule through August.
Would like to confirm we have come to a
consensus on NaNs.
What are we going to do about extended.
Fixed mode declarations (ahead of Alt exception)

*NaNs
Jim, Jeff, Prof. Kahan, and Jason presented.
Substantial discussion ensued.
The weight of history and opinion seemed
to weigh against the merged QNaN approach.
There seemed to be stronger support for
specifying non-commutative NaN propagation.

Joe argued that we should provide an informative
appendix to record the desired end user capabilities.
Where is the killer ap for the specific features.
There are four or five papers. A few rounding
mode references. Should list related papers.
Where is xblas using the C99 features?

Jason pointed out that the language community
uses a different language to discuss the things
we want.

Use it or lose it.

Portability is equiv.

Any piece of code that uses the contents of a
NaN payload is operating outside the spec.

David's thesis is there are no portable way to
take advantage of signaling NaNs.
We could take the "shall" out of the body and put
shall not raise Invalid on SNaNs in Appendix N.


April 15, 10 am - 5 pm. Clem Meas - Arithmetica Redwood City
  Draft review - 10-12 (with a hard stop at Noon)
  NaN Issue - Jeff
  Extended - Jim
  Language Issues - Jason
  Prior - Ivan
May 12,13 1-5, Jeff Kidder - Intel Santa Clara
June 16,17 1-5  Jim - HP Cupertino
July 21,22 1-5  Michael Parks - Sun Santa Clara
August 18,19 1-5 David Hough - Sun Menlo Park

Dan will ask for a 2 quarter extension.
The PAR for what we are doing is 754.

Options:
1. Leave NaNs as is in the body standard
2. Shall deliver one of the arguments, will have payload functions, and
quieting functions.
3.
  In the body: you should return a NaN with the same payload. The
standard doesn't say which NaN should be produced. The standard doesn't
say which sign a resulting NaN will have. Extract and insert functions
shall be defined. Payload will be defined.
  In appendix N: Payload shall be those one of the inputs. The standard
does not say which will be returned.
Yea - 7; No - 7; Abs -
Without the insert/extract.
Yea - 12; No - 4; Abs -
C99 has mechanisms to insert and extract.
Eric's objection: a bit manipulation. This bit manipulation would be
expected in the FP unit. Don't want to see bit type of operations put
into the standard.

Issue:
Changing the sign bits.

SNaN Option: Deprecate Signaling NaNs

What about casts? ... [dinner ensued]

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