1-- C97114A.ADA
2
3--                             Grant of Unlimited Rights
4--
5--     Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
6--     F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained
7--     unlimited rights in the software and documentation contained herein.
8--     Unlimited rights are defined in DFAR 252.227-7013(a)(19).  By making
9--     this public release, the Government intends to confer upon all
10--     recipients unlimited rights  equal to those held by the Government.
11--     These rights include rights to use, duplicate, release or disclose the
12--     released technical data and computer software in whole or in part, in
13--     any manner and for any purpose whatsoever, and to have or permit others
14--     to do so.
15--
16--                                    DISCLAIMER
17--
18--     ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
19--     DISCLOSED ARE AS IS.  THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED
20--     WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
21--     SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE
22--     OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
23--     PARTICULAR PURPOSE OF SAID MATERIAL.
24--*
25-- CHECK WHETHER A DELAY EXPRESSION FOLLOWING AN OPEN GUARD IS EVALUATED
26-- DIRECTLY AFTER THE GUARD OR ONLY AFTER ALL GUARDS HAVE BEEN
27-- EVALUATED, OR IN SOME MIXED ORDER SUCH THAT DELAY EXPRESSIONS ARE
28-- EVALUATED AFTER THEIR GUARDS ARE DETERMINED TO BE OPEN.
29
30-- RM 5/10/82
31-- SPS 11/21/82
32-- JBG 10/24/83
33-- PWN 09/11/94  REMOVED PRAGMA PRIORITY FOR ADA 9X.
34
35with Impdef;
36WITH REPORT; USE REPORT;
37WITH SYSTEM; USE SYSTEM;
38PROCEDURE C97114A IS
39
40
41     -- THE TASK WILL HAVE LAST PRIORITY ( PRIORITY'FIRST )
42
43     EVAL_ORDER  :  STRING (1..6)       := ( 1..6 => '*' );
44     EVAL_ORD    :  STRING (1..6)       := ( 1..6 => '*' );
45     INDEX       :  INTEGER             := 0;
46     DUMMY       :  INTEGER             := 0;
47
48
49     FUNCTION F1 (X:INTEGER) RETURN INTEGER IS
50     BEGIN
51          INDEX := INDEX + 1;
52          EVAL_ORDER (INDEX) := 'F';    -- 123: FGH
53          EVAL_ORD   (INDEX) := 'G';    -- 123: GGG ( 'G' FOR 'GUARD' )
54          RETURN ( IDENT_INT(7) );
55     END F1;
56
57
58     FUNCTION F2 (X:INTEGER) RETURN INTEGER IS
59     BEGIN
60          INDEX := INDEX + 1;
61          EVAL_ORDER (INDEX) := 'G';
62          EVAL_ORD   (INDEX) := 'G';
63          RETURN ( IDENT_INT(7) );
64     END F2;
65
66
67     FUNCTION F3 (X:INTEGER) RETURN INTEGER IS
68     BEGIN
69          INDEX := INDEX + 1;
70          EVAL_ORDER (INDEX) := 'H';
71          EVAL_ORD   (INDEX) := 'G';
72          RETURN ( IDENT_INT(7) );
73     END F3;
74
75
76     FUNCTION  D1( X:INTEGER )  RETURN DURATION IS
77     BEGIN
78          INDEX := INDEX + 1;
79          EVAL_ORDER (INDEX) := 'A';    -- 123: ABC
80          EVAL_ORD   (INDEX) := 'D';    -- 123: DDD ( 'D' FOR 'DELAY' )
81          RETURN ( 1.0 );
82     END D1;
83
84
85     FUNCTION  D2( X:INTEGER )  RETURN DURATION IS
86     BEGIN
87          INDEX := INDEX + 1;
88          EVAL_ORDER (INDEX) := 'B';
89          EVAL_ORD   (INDEX) := 'D';
90          RETURN ( 2.0 );
91     END D2;
92
93
94     FUNCTION  D3( X:INTEGER )  RETURN DURATION IS
95     BEGIN
96          INDEX := INDEX + 1;
97          EVAL_ORDER (INDEX) := 'C';
98          EVAL_ORD   (INDEX) := 'D';
99          RETURN ( 3.0 );
100     END D3;
101
102     FUNCTION POS_OF (FUNC : CHARACTER) RETURN INTEGER  IS
103     BEGIN
104          FOR I IN EVAL_ORDER'RANGE LOOP
105               IF EVAL_ORDER(I) = FUNC THEN
106                    RETURN I;
107               END IF;
108          END LOOP;
109          FAILED ("DID NOT FIND LETTER " & FUNC);
110          RETURN 0;
111     END POS_OF;
112
113BEGIN
114
115
116     TEST ("C97114A", "CHECK THAT THE DELAY EXPRESSIONS ARE" &
117                      " EVALUATED AFTER THE GUARDS BUT"      &
118                      " BEFORE THE RENDEZVOUS IS ATTEMPTED"  );
119
120
121     DECLARE
122
123
124          TASK T IS
125
126
127               ENTRY E1;
128
129          END T;
130
131
132          TASK BODY T IS
133          BEGIN
134
135
136               WHILE  E1'COUNT = 0  -- IF  E1  NOT YET CALLED, THEN GIVE
137               LOOP                 --     THE MAIN TASK AN OPPORTUNITY
138                    DELAY  10.01 * Impdef.One_Second;   --     TO ISSUE THE CALL.
139               END LOOP;
140
141
142               SELECT
143
144                         ACCEPT  E1;
145
146               OR
147
148                    WHEN  6 + F1(7) = 13  =>
149                         DELAY  D1( DUMMY ) * Impdef.One_Second;
150
151               OR
152
153                    WHEN  6 + F2(7) = 13  =>
154                         DELAY  D2( DUMMY ) * Impdef.One_Second;
155
156               OR
157
158                    WHEN  6 + F3(7) = 13  =>
159                         DELAY  D3( DUMMY ) * Impdef.One_Second;
160
161               END SELECT;
162
163
164          END T;
165
166
167     BEGIN
168
169          T.E1;
170
171     END; -- END OF BLOCK CONTAINING THE ENTRY CALLS
172
173
174     COMMENT ("EVALUATIONS WERE DONE IN THE ORDER " & EVAL_ORD);
175     COMMENT ("FUNCTIONS WERE CALLED IN THE ORDER " & EVAL_ORDER);
176
177     IF EVAL_ORD = "GGGDDD" THEN
178          COMMENT ("ALL GUARDS EVALUATED FIRST");
179     ELSIF EVAL_ORD = "GDGDGD" THEN
180          COMMENT ("DELAY EXPRESSION EVALUATED AFTER EACH GUARD");
181     END IF;
182
183-- CHECK THAT GUARDS ARE ALWAYS EVALUATED BEFORE DELAY EXPRESSIONS
184
185     IF   POS_OF ('F') > POS_OF ('A') OR
186          POS_OF ('G') > POS_OF ('B') OR
187          POS_OF ('H') > POS_OF ('C') THEN
188               FAILED ("A DELAY EXPRESSION WAS EVALUATED BEFORE ITS " &
189                       "GUARD");
190     END IF;
191
192
193     RESULT;
194
195
196END  C97114A;
197