1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
-- 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;
|
