Glenn Fowler wrote: > On Tue, 03 Mar 2009 16:40:43 +0100 Roland Mainz wrote: > > Glenn Fowler wrote: > > > the second field contains letters that correspond to the > > > optional compile-time SHOPT_* features (when ksh was built) > > > > > > A SHOPT_AUDIT > > > B SHOPT_BASH > > > Is it possible reserve "D" (and "typeset -D") for "IEEE 754-2008-style > > decimal floating point", please (this differs from normal IEEE754 > > floating-point math that it uses bash10 instead of base2 and is needed > ^^^^^^ > (maybe you need a break from shell hacking?:)
No, I am serious in this case. IEEE 754-2008 supports two _different_ floating-point formats: a) The "traditional" base2 floating-point format we all know from IEEE 754-1985 and ISO C99 and ISO C++ etc. b) The "new" base10 (="decimal") floating-point format (which comes with new headers, library functions (see decNumber below) and C datatypes) These two are different entities, use different datatypes and can be used in the same application (the difference are in binary representation (decimal floating-point uses densely packed floating-point), rounding and text<--->binary conversions and other little details). > > for stuff like financial applications (somewhere I've queued a longer > > email abóut this in my drafts folder)) ? > > what are the coding/runtime mechanisms for IEEE 754-2008 decimal floating > point 1. See http://en.wikipedia.org/wiki/Decimal_floating_point#IEEE_754-2008_encoding 2. Newer compilers like gcc >= 4.2 support "Decimal Floating Point" directly (e.g. it is expected that in the future all newer compilers will support decimal floating-point - the transition may need another four or five years for all platforms (IBM is likely going to lead in this area since their high-end Power hardware supports decimal floating point in hardware already)). 3. IBM provides the ANSI-C "decNumber" library (see http://www.alphaworks.ibm.com/tech/decnumber) under a MIT license for compilers/platforms which do not support decimal-floating-point yet > recall that ast does its own string<=>fp conversions > these work for IEEE 754 > but no provisions have been made for IEEE 754-2008 > (it may be that no provisions are necessary) No provisions are neccesary for the traditional IEEE 754-2008 base2 floating-point math ([a] above) ... but base10 math ([b] above) is something completely new. > in particular, can a single process switch between IEEE 754 and IEEE 754-2008? Yes, see above. Both [a] and [b] are seperate things. ---- Bye, Roland -- __ . . __ (o.\ \/ /.o) [email protected] \__\/\/__/ MPEG specialist, C&&JAVA&&Sun&&Unix programmer /O /==\ O\ TEL +49 641 3992797 (;O/ \/ \O;) _______________________________________________ ast-users mailing list [email protected] https://mailman.research.att.com/mailman/listinfo/ast-users
