F.1 Machine_Radix Attribute Definition Clause
Static Semantics
{
AI12-0272-1}
The representation attribute
Machine_Radix may be specified for a decimal first subtype (see
3.5.9)
via an
attribute_definition_clause;
the expression of such a clause shall be static, and its value shall
be 2 or 10. A value of 2 implies a binary base range; a value of 10 implies
a decimal base range.
Ramification: In the absence of a Machine_Radix
clause, the choice of 2 versus 10 for S'Machine_Radix is not specified.
Aspect Description for Machine_Radix:
Radix (2 or 10) that is used to represent a decimal fixed point type.
Implementation Advice
Packed decimal should be used as the internal representation
for objects of subtype S when S'Machine_Radix = 10.
Implementation Advice: Packed decimal
should be used as the internal representation for objects of subtype
S when S'Machine_Radix = 10.
Discussion: {
AI05-0229-1}
The intent of a decimal Machine_Radix attribute definition clause is
to allow the programmer to declare an Ada decimal data object whose representation
matches a particular COBOL implementation's representation of packed
decimal items. The Ada object may then be passed to an interfaced COBOL
program that takes a packed decimal data item as a parameter, assuming
that convention COBOL has been specified for the Ada object's type with
an aspect Convention.
Additionally, the Ada compiler may choose to
generate arithmetic instructions that exploit the packed decimal representation.
Examples
Example of Machine_Radix
attribute definition clause:
type Money is delta 0.01 digits 15;
for Money'Machine_Radix use 10;
Wording Changes from Ada 2012
{
AI12-0272-1}
Clarified that Machine_Radix is a representation aspect.
Ada 2005 and 2012 Editions sponsored in part by Ada-Europe
