cxg2012.a

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      exception
         when Constraint_Error =>
            Report.Failed ("Constraint_Error raised in Special Value Test");
         when others =>
            Report.Failed ("exception in Special Value Test");
      end Special_Value_Test;


      procedure Small_Range_Test is
      -- Several checks over the range 1/radix .. 1
         A : constant Real := 1.0 / Real (Real'Machine_Radix);
         B : constant Real := 1.0;
         X : Real;
         -- In the cases below where the expected result is
         -- inexact we allow an additional error amount of
         -- 1.0 * Model_Epsilon to account for that error.
         -- This is accomplished by the factor of 1.25 times
         -- the computed error bound (which is > 4.0) thus
         -- increasing the error bound by at least
         -- 1.0 * Model_Epsilon
      begin
         Accuracy_Error_Reported := False;  -- reset
         for I in 0..Max_Samples loop
            X :=  Real'Machine((B - A) * Real (I) / Real (Max_Samples) + A);

            Check (X ** 1.0, X,  -- exact result required
                   "Small range" & Integer'Image (I) & ": " &
                   Real'Image (X) & " ** 1.0",
                   0.0);

            Check ((X*X) ** 1.5, X**3,  X*X, 1.5,
                   "Small range" & Integer'Image (I) & ": " &
                   Real'Image (X*X) & " ** 1.5",
                   1.25);

            Check (X ** 13.5, 1.0 / (X ** (-13.5)),  X, 13.5,
                   "Small range" & Integer'Image (I) & ": " &
                   Real'Image (X) & " ** 13.5",
                   2.0);   -- 2 ** computations

            Check ((X*X) ** 1.25, X**(2.5),  X*X, 1.25,
                   "Small range" & Integer'Image (I) & ": " &
                   Real'Image (X*X) & " ** 1.25",
                   2.0);   -- 2 ** computations

            if Accuracy_Error_Reported then
              -- only report the first error in this test in order to keep
              -- lots of failures from producing a huge error log
              return;
            end if;

         end loop;

      exception
         when Constraint_Error =>
            Report.Failed
               ("Constraint_Error raised in Small Range Test");
         when others =>
            Report.Failed ("exception in Small Range Test");
      end Small_Range_Test;


      procedure Large_Range_Test is
      -- Check over the range A to B where A is 1.0 and
      -- B is a large value.
         A : constant Real := 1.0;
         B : Real;
         X : Real;
         Iteration : Integer := 0;
         Subtest : Character := 'X';
      begin
         -- upper bound of range should be as large as possible where
         -- B**3 is still valid.
         B := Real'Safe_Last ** 0.333;
         Accuracy_Error_Reported := False;  -- reset
         for I in 0..Max_Samples loop
            Iteration := I;
            Subtest := 'X';
            X :=  Real'Machine((B - A) * (Real (I) / Real (Max_Samples)) + A);

            Subtest := 'A';
            Check (X ** 1.0, X,  -- exact result required
                   "Large range" & Integer'Image (I) & ": " &
                   Real'Image (X) & " ** 1.0",
                   0.0);

            Subtest := 'B';
            Check ((X*X) ** 1.5, X**3,  X*X, 1.5,
                   "Large range" & Integer'Image (I) & ": " &
                   Real'Image (X*X) & " ** 1.5",
                   1.25);   -- inexact expected result

            Subtest := 'C';
            Check ((X*X) ** 1.25, X**(2.5),  X*X, 1.25,
                   "Large range" & Integer'Image (I) & ": " &
                   Real'Image (X*X) & " ** 1.25",
                   2.0);   -- two ** operators

            if Accuracy_Error_Reported then
              -- only report the first error in this test in order to keep
              -- lots of failures from producing a huge error log
              return;
            end if;

         end loop;
      exception
         when Constraint_Error =>
            Report.Failed
               ("Constraint_Error raised in Large Range Test" &
                Integer'Image (Iteration) & Subtest);
         when others =>
            Report.Failed ("exception in Large Range Test" &
                Integer'Image (Iteration) & Subtest);
      end Large_Range_Test;


      procedure Exception_Test is
         X1, X2, X3, X4 : Real;
      begin
         begin
            X1 := 0.0 ** (-1.0);
            Report.Failed ("exception not raised for 0**-1");
         exception
            when Ada.Numerics.Argument_Error =>
               Report.Failed ("argument_error raised instead of" &
                              " constraint_error for 0**-1");
            when Constraint_Error => null;   -- ok
            when others =>
               Report.Failed ("wrong exception raised for 0**-1");
         end;

         begin
            X2 := 0.0 ** 0.0;
            Report.Failed ("exception not raised for 0**0");
         exception
            when Ada.Numerics.Argument_Error =>  null;  -- ok
            when Constraint_Error =>
               Report.Failed ("constraint_error raised instead of" &
                              " argument_error for 0**0");
            when others =>
               Report.Failed ("wrong exception raised for 0**0");
         end;

         begin
            X3 := (-1.0) ** 1.0;
            Report.Failed ("exception not raised for -1**1");
         exception
            when Ada.Numerics.Argument_Error =>  null;  -- ok
            when Constraint_Error =>
               Report.Failed ("constraint_error raised instead of" &
                              " argument_error for -1**1");
            when others =>
               Report.Failed ("wrong exception raised for -1**1");
         end;

         begin
            X4 := (-2.0) ** 2.0;
            Report.Failed ("exception not raised for -2**2");
         exception
            when Ada.Numerics.Argument_Error =>  null;  -- ok
            when Constraint_Error =>
               Report.Failed ("constraint_error raised instead of" &
                              " argument_error for -2**2");
            when others =>
               Report.Failed ("wrong exception raised for -2**2");
         end;

         -- optimizer thwarting
         if Report.Ident_Bool (False) then
            Report.Comment (Real'Image (X1+X2+X3+X4));
         end if;
      end Exception_Test;


      procedure Do_Test is
      begin
         Real_To_Integer_Test;
         Special_Value_Test;
         Small_Range_Test;
         Large_Range_Test;
         Exception_Test;
      end Do_Test;
   end Generic_Check;

   -----------------------------------------------------------------------
   -----------------------------------------------------------------------
   package Float_Check is new Generic_Check (Float);

   -- check the floating point type with the most digits
   type A_Long_Float is digits System.Max_Digits;
   package A_Long_Float_Check is new Generic_Check (A_Long_Float);

   -----------------------------------------------------------------------
   -----------------------------------------------------------------------


begin
   Report.Test ("CXG2012",
                "Check the accuracy of the ** operator");

   if Verbose then
      Report.Comment ("checking Standard.Float");
   end if;

   Float_Check.Do_Test;

   if Verbose then
      Report.Comment ("checking a digits" &
                      Integer'Image (System.Max_Digits) &
                      " floating point type");
   end if;

   A_Long_Float_Check.Do_Test;


   Report.Result;
end CXG2012;