encoders should be written non-recursively or impose a limit on
list length.
9. IANA Considerations
It is possible, if not likely, that new data types will be added to
XDR in the future. The process for adding new types is via a
standards track RFC and not registration of new types with IANA.
Standards track RFCs that update or replace this document should be
documented as such in the RFC Editor’s database of RFCs.
10. Trademarks and Owners
SUN WORKSTATION Sun Microsystems, Inc.
VAX Hewlett-Packard Company
IBM-PC International Business Machines Corporation
Cray Cray Inc.
NFS Sun Microsystems, Inc.
Ethernet Xerox Corporation.
Motorola 68000 Motorola, Inc.
IBM 370 International Business Machines Corporation
11. ANSI/IEEE Standard 754-1985
The definition of NaNs, signed zero and infinity, and denormalized
numbers from [IEEE] is reproduced here for convenience. The
definitions for quadruple-precision floating point numbers are
analogs of those for single and double-precision floating point
numbers and are defined in [IEEE].
In the following, ’S’ stands for the sign bit, ’E’ for the exponent,
and ’F’ for the fractional part. The symbol ’u’ stands for an
undefined bit (0 or 1).
For single-precision floating point numbers:
Type S (1 bit) E (8 bits) F (23 bits)
---- --------- ---------- -----------
signalling NaN u 255 (max) .0uuuuu---u
(with at least
one 1 bit)
quiet NaN u 255 (max) .1uuuuu---u
negative infinity 1 255 (max) .000000---0
positive infinity 0 255 (max) .000000---0
negative zero 1 0 .000000---0
positive zero 0 0 .000000---0
For double-precision floating point numbers:
Type S (1 bit) E (11 bits) F (52 bits)
---- --------- ----------- -----------
signalling NaN u 2047 (max) .0uuuuu---u
(with at least
one 1 bit)
quiet NaN u 2047 (max) .1uuuuu---u
negative infinity 1 2047 (max) .000000---0
positive infinity 0 2047 (max) .000000---0
negative zero 1 0 .000000---0
positive zero 0 0 .000000---0
For quadruple-precision floating point numbers:
Type S (1 bit) E (15 bits) F (112 bits)
---- --------- ----------- ------------
signalling NaN u 32767 (max) .0uuuuu---u
(with at least
one 1 bit)
quiet NaN u 32767 (max) .1uuuuu---u
negative infinity 1 32767 (max) .000000---0
positive infinity 0 32767 (max) .000000---0
negative zero 1 0 .000000---0
positive zero 0 0 .000000---0
Subnormal numbers are represented as follows:
Precision Exponent Value
--------- -------- -----
Single 0 (-1)**S * 2**(-126) * 0.F
Double 0 (-1)**S * 2**(-1022) * 0.F
Quadruple 0 (-1)**S * 2**(-16382) * 0.F
12. Normative References
[IEEE] "IEEE Standard for Binary Floating-Point Arithmetic",
ANSI/IEEE Standard 754-1985, Institute of Electrical and
Electronics Engineers, August 1985.
13. Informative References
[KERN] Brian W. Kernighan & Dennis M. Ritchie, "The C Programming
Language", Bell Laboratories, Murray Hill, New Jersey, 1978.
[COHE] Danny Cohen, "On Holy Wars and a Plea for Peace", IEEE
Computer, October 1981.
[COUR] "Courier: The Remote Procedure Call Protocol", XEROX
Corporation, XSIS 038112, December 1981.
[SPAR] "The SPARC Architecture Manual: Version 8", Prentice Hall,
ISBN 0-13-825001-4.
[HPRE] "HP Precision Architecture Handbook", June 1987, 5954-9906.
14. Acknowledgements
Bob Lyon was Sun’s visible force behind ONC RPC in the 1980s. Sun
Microsystems, Inc., is listed as the author of RFC 1014. Raj
Srinivasan and the rest of the old ONC RPC working group edited RFC
1014 into RFC 1832, from which this document is derived. Mike Eisler
and Bill Janssen submitted the implementation reports for this
standard. Kevin Coffman, Benny Halevy, and Jon Peterson reviewed
this document and gave feedback. Peter Astrand and Bryan Olson
pointed out several errors in RFC 1832 which are corrected in this
document.
Editor’s Address
Mike Eisler
5765 Chase Point Circle
Colorado Springs, CO 80919
USA
Phone: 719-599-9026
EMail: email2mre-rfc4506@yahoo.com
Please address comments to: nfsv4@ietf.org
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