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F.2 The Package Decimal

Static Semantics

(1)

The library package Decimal has the following declaration:

(2)
       package Ada.Decimal is
          pragma Pure(Decimal);
(3)
          Max_Scale : constant := implementation-defined;
          Min_Scale : constant := implementation-defined;
(4)
          Min_Delta : constant := 10.0**(-Max_Scale);
          Max_Delta : constant := 10.0**(-Min_Scale);
(5)
          Max_Decimal_Digits : constant := implementation-defined;
(6)
          generic
             type Dividend_Type  is delta <> digits <>;
             type Divisor_Type   is delta <> digits <>;
             type Quotient_Type  is delta <> digits <>;
             type Remainder_Type is delta <> digits <>;
          procedure Divide (Dividend  : in Dividend_Type;
                            Divisor   : in Divisor_Type;
                            Quotient  : out Quotient_Type;
                            Remainder : out Remainder_Type);
          pragma Convention(Intrinsic, Divide);
(7)
       end Ada.Decimal;

(8)

Max_Scale is the largest N such that 10.0**(-N) is allowed as a decimal type's delta. Its type is universal_integer.

(9)

Min_Scale is the smallest N such that 10.0**(-N) is allowed as a decimal type's delta. Its type is universal_integer.

(10)

Min_Delta is the smallest value allowed for delta in a decimal_fixed_point_definition. Its type is universal_real.

(11)

Max_Delta is the largest value allowed for delta in a decimal_fixed_point_definition. Its type is universal_real.

(12)

Max_Decimal_Digits is the largest value allowed for digits in a decimal_fixed_point_definition. Its type is universal_integer.

Static Semantics

(13)

The effect of Divide is as follows. The value of Quotient is Quotient_Type(Dividend/Divisor). The value of Remainder is Remainder_Type(Intermediate), where Intermediate is the difference between Dividend and the product of Divisor and Quotient; this result is computed exactly.

Implementation Requirements

(14)

Decimal.Max_Decimal_Digits shall be at least 18.

(15)

Decimal.Max_Scale shall be at least 18.

(16)

Decimal.Min_Scale shall be at most 0.

NOTES

(17)

(1) The effect of division yielding a quotient with control over rounding versus truncation is obtained by applying either the function attribute Quotient_Type'Round or the conversion Quotient_Type to the expression Dividend/Divisor.

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