Date Posted: December 14, 2001
Update: July 15, 2008 Version 3.61 is a maintenance and performance update that greatly improves the performance of some addition and square root operations; see the changes list in the documentation for details.
What is decNumber?
decNumber is a high-performance decimal arithmetic library in ANSI C, especially suitable for commercial and human-oriented applications.
How does it work?
The library consists of several modules, organized as though they were classes in an object-oriented implementation. These provide direct support for the following:
- integer, fixed-point, and floating-point decimal numbers (so no conversions between these forms is necessary)
- arbitrary precision values (up to a billion digits) and special values, such as Infinity and Not-a-Number (NaN)
- conversions to and from the densely packed floating-point decimal formats (8- and 16-byte) proposed for hardware implementation
- conversions to and from Packed Decimal (4-bit Binary Coded Decimal) numbers
- active (signaling) or passive (accumulated status) error handling
Comprehensive documentation is provided, including a User's Guide with detailed examples.
About the technology author(s)
Mike Cowlishaw was named an IBM® Fellow in 1990, which allows him to work on projects of his own choosing.
In 1998 and 1999, he was Project Editor for the ECMAScript (JavaScript) international standard. Since 1999, he has been working on new decimal arithmetic packages, including IBM""s BigDecimal class for Java™ and encodings for decimal hardware representations. Mr. Cowlishaw is the author of the Standard Decimal Arithmetic specifications, and he is the Specification Lead for decimal arithmetic enhancements in Java. He is active in the work of several standards organizations, including ECMA, ISO, IEEE, and W3C.
Mr. Cowlishaw was a founding member of the IBM Academy of Technology in 1989; he was elected to its Technology Council from 1989 to 1993 and again from 1997 to 2000. He has received many IBM awards, including several Outstanding Technical Achievement and Distinguished Contribution awards and a Corporate Award for Outstanding Technical Innovation. In 1999, Mr. Cowlishaw was elected a Fellow of the Royal Academy of Engineering, and he is a Visiting Professor in the Department of Computer Science at the University of Warwick.
Mr. Cowlishaw can be reached through e-mail.
