test.cpp revision 12855:588919e0e4aa 
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20/*****************************************************************************
21
22  test.cpp --
23
24  Original Author: Martin Janssen, Synopsys, Inc., 2002-02-15
25
26 *****************************************************************************/
27
28/*****************************************************************************
29
30  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
31  changes you are making here.
32
33      Name, Affiliation, Date:
34  Description of Modification:
35
36 *****************************************************************************/
37
38/*
39I believe there is a bug in SystemC 2.0 beta 1 which
40causes simulation to end prematurely in certain cases.
41Specifically, if an event notification occurs at a particular
42time but no processes are ready to run at that time,
43simulation will end. However, there may still be processes
44that need to be run at future times.
45
46Below I've included an example which demonstrates the bug,
47and below that I've provided a proposed fix for the bug.
48
49// This SystemC 2.0 example shows the bug...
50*/
51
52#include <systemc.h>
53
54class top : public sc_module
55{
56   public:
57     SC_HAS_PROCESS(top);
58
59     top(sc_module_name name) : sc_module(name)
60     {
61         SC_THREAD(main);
62     }
63
64     void main()
65     {
66         sc_event e;
67
68         // comment out the following line to see bug go away
69
70         e.notify(55, SC_NS);
71
72         for (int i = 0; i < 10; i++)
73         {
74           wait(10, SC_NS);
75           cout << "main thread at time " << sc_time_stamp() << endl;
76         }
77     }
78};
79
80int sc_main (int argc , char *argv[])
81{
82   top top1("Top1");
83   sc_start();
84   return 0;
85}
86
87/*
88/////// End of example
89
90The proposed fix for this in SystemC 2.0 beta 1 is:
91
92Edit src/sysc/kernel/sc_simcontext.cpp
93
94Lines 801-802, which read:
95
96// no more runnable processes
97break;
98
99Should be changed to read:
100
101// no runnable processes at current time, but maybe in future
102t = next_time();
103continue;
104
105The same changes should be applied at lines 845-846
106Then rebuild and reinstall the SystemC library.
107
108
109___________________________________________________
110Stuart Swan, Senior Architect
111System Level Design Group, Cadence Design Systems
112Building 11
1132670 Seely Avenue
114San Jose, CA 95134
115Phone: +1 408 895 4579
116Email: stuart@cadence.com
117___________________________________________________
118
119*/
120