S'Digits denotes the requested 
decimal precision for the subtype S. The value of this attribute is of 
the type 
universal_integer. The requested decimal precision of 
the base subtype of a floating point type 
T is defined to be the 
largest value of 
d for which 
ceiling(
d * log(10) / log(T'Machine_Radix)) + 
g <= T'Model_Mantissa
where g is 0 if Machine_Radix is a positive power of 10 and 1 otherwise. 
 
42  
The predefined operations 
of a floating point type include the assignment operation, qualification, 
the membership tests, and explicit conversion to and from other numeric 
types. They also include the relational operators and the following predefined 
arithmetic operators: the binary and unary adding operators – and 
+, certain multiplying operators, the unary operator 
abs, and 
the exponentiation operator.
 
43  As for all types, objects of a floating 
point type have Size and Address attributes (see 
13.3). 
Other attributes of floating point types are defined in 
A.5.3.