More on Ada and decimal

[Marc.Graham@SEI.CMU.EDU]

A Mr. Borman claims that asking for decimal support is `thoughtless'
and that no one would use floating point computations for dollars. The
last claim is true. I am looking for fixed point decimal support. 

Mr. Borman suggests a solution of counting in binary and maintaining
(implicitly or explicitly) a decimal scale. Such a solution is
functionally accurate and viable in some circumstances, but it is not
the entire story. If it were, there would be no such thing as decimal
hardware. The advantages of decimal hardware are twofold:

1. Decimal hardware typically allows for computations on much larger
numbers than the binary (fixed point) hardware; e.g. 10**31 as
contrasted to 2**32;

2. It eliminates the necessity to convert between binary and decimal
representations. If the commonly held view of commercial applications,
little calculation and lots of io, is accurate, then the savings in
conversion costs outweigh the loss in compute speed. 

Marc H. Graham                    Software Engineering Institute
marc@sei.cmu.edu                  Carnegie Mellon University
(412) 268 7784                    Pittsburgh, PA   15213