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-- C35902D.ADA

--                             Grant of Unlimited Rights

--

--     Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,

--     F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained 

--     unlimited rights in the software and documentation contained herein.

--     Unlimited rights are defined in DFAR 252.227-7013(a)(19).  By making 

--     this public release, the Government intends to confer upon all 

--     recipients unlimited rights  equal to those held by the Government.  

--     These rights include rights to use, duplicate, release or disclose the 

--     released technical data and computer software in whole or in part, in 

--     any manner and for any purpose whatsoever, and to have or permit others 

--     to do so.

--

--                                    DISCLAIMER

--

--     ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR

--     DISCLOSED ARE AS IS.  THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED 

--     WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE

--     SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE 

--     OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A

--     PARTICULAR PURPOSE OF SAID MATERIAL.

--*

-- CHECK THAT THE BINARY POINT IN THE MANTISSA OF A FIXED POINT NUMBER

-- CAN LIE OUTSIDE THE MANTISSA (EITHER TO THE LEFT OR TO THE RIGHT).

-- WRG 7/18/86

WITH REPORT; USE REPORT;

WITH SYSTEM; USE SYSTEM;

PROCEDURE C35902D IS

BEGIN

     TEST ("C35902D", "CHECK THAT THE BINARY POINT IN THE MANTISSA " &

                      "OF A FIXED POINT NUMBER CAN LIE OUTSIDE THE " &

                      "MANTISSA (EITHER TO THE LEFT OR TO THE RIGHT)");

     COMMENT ("VALUE OF SYSTEM.MAX_MANTISSA IS" &

              POSITIVE'IMAGE(MAX_MANTISSA) );

  A: DECLARE

          RS : CONSTANT := 2.0;

          TYPE ONE_TO_THE_RIGHT IS

               DELTA RS

               RANGE -(2.0 ** (MAX_MANTISSA+1) ) ..

                       2.0 ** (MAX_MANTISSA+1);

               -- THE BINARY POINT IS ONE PLACE TO THE RIGHT OF THE

               -- LARGEST POSSIBLE MANTISSA.

          R1, R2 : ONE_TO_THE_RIGHT;

     BEGIN

          R1 := RS;

          FOR I IN POSITIVE RANGE 1 .. MAX_MANTISSA - 1 LOOP

               R1 := R1 * IDENT_INT (2);

          END LOOP;

          R2 := R1 - RS;

          R2 := R2 + R1;

          -- AT THIS POINT, R2 SHOULD EQUAL ONE_TO_THE_RIGHT'LARGE.

          R2 := -R2;

          R2 := R2 + (R1 - RS);

          FOR I IN POSITIVE RANGE 1 .. MAX_MANTISSA - 1 LOOP

               R2 := R2 / IDENT_INT (2);

          END LOOP;

          IF R2 /= -RS THEN

               FAILED ("IDENTITY-PRESERVING OPERATIONS ARE FLAKY - A");

          END IF;

     EXCEPTION

          WHEN OTHERS =>

               FAILED ("EXCEPTION RAISED - A");

     END A;

  B: DECLARE

          LS : CONSTANT := 2.0 ** (-(MAX_MANTISSA+1) );

          TYPE ONE_TO_THE_LEFT IS

               DELTA LS

               RANGE -(2.0 ** (-1) ) ..

                       2.0 ** (-1);

               -- THE BINARY POINT IS ONE PLACE TO THE LEFT OF THE

               -- LARGEST POSSIBLE MANTISSA.

          L1, L2 : ONE_TO_THE_LEFT;

     BEGIN

          L1 := LS;

          FOR I IN POSITIVE RANGE 1 .. MAX_MANTISSA - 1 LOOP

               L1 := L1 * IDENT_INT (2);

          END LOOP;

          L2 := L1 - LS;

          L2 := L2 + L1;

          -- AT THIS POINT, L2 SHOULD EQUAL ONE_TO_THE_LEFT'LARGE.

          L2 := -L2;

          L2 := L2 + (L1 - LS);

          FOR I IN POSITIVE RANGE 1 .. MAX_MANTISSA - 1 LOOP

               L2 := L2 / IDENT_INT (2);

          END LOOP;

          IF L2 /= -LS THEN

               FAILED ("IDENTITY-PRESERVING OPERATIONS ARE FLAKY - B");

          END IF;

     EXCEPTION

          WHEN OTHERS =>

               FAILED ("EXCEPTION RAISED - B");

     END B;

     RESULT;

END C35902D;