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G.2.2 ModelOriented Attributes of Floating Point Types
1
In implementations that support the Numerics Annex,
the modeloriented attributes of floating point types shall yield the
values defined here, in both the strict and the relaxed modes. These
definitions add conditions to those in
A.5.3.
Static Semantics
2
For every subtype
S of a floating point type T:
3
 S'Model_Mantissa

Yields the number of digits in the mantissa of the canonical form of
the model numbers of T (see A.5.3).
The value of this attribute shall be greater than or equal to Ceiling(d
· log(10) / log(T'Machine_Radix)) + 1, where d is
the requested decimal precision of T. In addition, it shall be
less than or equal to the value of T'Machine_Mantissa. This attribute
yields a value of the type universal_integer.
4
 S'Model_Emin

Yields the minimum exponent of the canonical form of the model numbers
of T (see A.5.3). The value of this
attribute shall be greater than or equal to the value of T'Machine_Emin.
This attribute yields a value of the type universal_integer.
5
 S'Safe_First

Yields the lower bound of the safe range of T. The value of this
attribute shall be a model number of T and greater than or equal
to the lower bound of the base range of T. In addition, if T
is declared by a floating_point_definition
or is derived from such a type, and the floating_point_definition
includes a real_range_specification
specifying a lower bound of lb, then the value of this attribute
shall be less than or equal to lb; otherwise, it shall be less
than or equal to 10.0 ^{4 ·
d}, where d is the requested decimal
precision of T. This attribute yields a value of the type universal_real.
6
 S'Safe_Last

Yields the upper bound of the safe range of T. The value of this
attribute shall be a model number of T and less than or equal
to the upper bound of the base range of T. In addition, if T
is declared by a floating_point_definition
or is derived from such a type, and the floating_point_definition
includes a real_range_specification
specifying an upper bound of ub, then the value of this attribute
shall be greater than or equal to ub; otherwise, it shall be greater
than or equal to 10.0 ^{4 ·
d}, where d is the requested decimal precision
of T. This attribute yields a value of the type universal_real.
7
 S'Model

Denotes a function (of a parameter X) whose specification is given
in A.5.3. If X is a model number of
T, the function yields X; otherwise, it yields the value
obtained by rounding or truncating X to either one of the adjacent
model numbers of T. Constraint_Error
is raised if the resulting model number is outside the safe range of
S. A zero result has the sign of X when S'Signed_Zeros is True.
8
Subject to the constraints
given above, the values of S'Model_Mantissa and S'Safe_Last are to be
maximized, and the values of S'Model_Emin and S'Safe_First minimized,
by the implementation as follows:
9
 First, S'Model_Mantissa is set to
the largest value for which values of S'Model_Emin, S'Safe_First, and
S'Safe_Last can be chosen so that the implementation satisfies the strictmode
requirements of G.2.1 in terms of the model
numbers and safe range induced by these attributes.
10
 Next, S'Model_Emin is set to the smallest
value for which values of S'Safe_First and S'Safe_Last can be chosen
so that the implementation satisfies the strictmode requirements of
G.2.1 in terms of the model numbers and safe
range induced by these attributes and the previously determined value
of S'Model_Mantissa.
11
 Finally, S'Safe_First and S'Safe_last
are set (in either order) to the smallest and largest values, respectively,
for which the implementation satisfies the strictmode requirements of
G.2.1 in terms of the model numbers and safe
range induced by these attributes and the previously determined values
of S'Model_Mantissa and S'Model_Emin.
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