-- This package contains the Leading and Trailing parts of
-- numbers that can not be exactly represented on computers
-- with a MACHINE_RADIX that is a power of 2.

-- The leading part plus the trailing part represent the constant to
-- at least five bits greater accuracy than can be represented by
-- 128 bit floating point. The leading part can be represented
-- exactly in about 5 bits. The trailing part has significant digits
-- accurate to a model interval. 

generic
  type FLOAT_TYPE is digits <>;
package TEST_MATH_LT_CONSTANTS is
-- The enumeration literals are used to retrieve the Leading part, Trailing
-- part and machine approximation.

  type TYPE_LT is ( ZERO_LT, PI_LT, PI2_LT, PI4_LT, E_LT);

  procedure FIND_LT( NAME_LT : TYPE_LT;
                     LEAD    : out FLOAT_TYPE;  -- exact
                     TRAIL   : out FLOAT_TYPE;  -- approximate + 5 bits
                     MACHINE : out FLOAT_TYPE); -- approximate number
end TEST_MATH_LT_CONSTANTS;
package body TEST_MATH_LT_CONSTANTS is
  procedure FIND_LT( NAME_LT : TYPE_LT;
                     LEAD    : out FLOAT_TYPE;    -- exact
                     TRAIL   : out FLOAT_TYPE;    -- approximate + 5 bits
                     MACHINE : out FLOAT_TYPE) is -- approximate number
  begin
    case NAME_LT is
      when ZERO_LT  =>
        LEAD :=    0.0;
        TRAIL :=   0.0;
        MACHINE := 0.0;
      when PI_LT =>
        LEAD :=    3.125;
        TRAIL :=   0.01659_26535_89793_23846_26433_83279_50288_41971 ;
        MACHINE := 3.14159_26535_89793_23846_26433_83279_50288_41971 ;
      when PI2_LT =>
        LEAD :=    1.5625;
        TRAIL :=   0.00829_63267_94896_61923_13216_91639_75144_209858;
        MACHINE := 1.57079_63267_94896_61923_13216_91639_75144_209858;
      when PI4_LT =>
        LEAD :=    0.78125;
        TRAIL :=   0.00414_81633_97448_30961_56608_45819_87572_104929;
        MACHINE := 0.78539_81633_97448_30961_56608_45819_87572_104929;
      when E_LT =>
        LEAD :=    2.625;
        TRAIL :=   0.09328_18284_59045_23536_02874_71352_66249_77572 ;
        MACHINE := 2.71828_18284_59045_23536_02874_71352_66249_77572 ;
    end case;
  end FIND_LT;
end TEST_MATH_LT_CONSTANTS;