Implicit Warning: Implicit Warning: Implicit signal consumption signal consumption signal consumption signal consumption of signal of signal L_DataReq of signal L_DataReq of signal L_ReleaseReq Sender: <<Block Sender: <<Block L_ReleaseReq Sender: <<Block DLCa>> dispatch:1 DLCa>> dispatch: Sender: <<Block DLCb>> dispatch:1 Receiver: <<Block Receiver: <<Block DLCa>> dispatch:1 Receiver: <<Block DLCa>> DLC:2 DLCa>> DLC:1 Receiver: <<Block DLCb>> DLC:1 Depth: 56 Depth: 56 DLCa>> DLC:2 Depth: 82 Depth: 56 Figure 7.19 The Report Viewer (11 reports) F. The seventh (or sixth) box from the left shows that signal L_ReleaseReq, transmitted by process dispatch to instance 2 of process DLC, has been discarded (implicit signal consumption). We have chosen this report because its depth is only 56, the left-most having a longer depth (such as 92). The MSC trace is shorter and easier to understand. G. Double-click on this box: the MSC Editor displays the trace of the scenario leading to the error; the end of this trace is shown in Figure 7.20. MSC bug_exh2 process process process <<Block DLCa>x Block DLCa>> <<Block DLCb>> dispatch dispatch env_0 dispatch_3 DLC_7 AtoB_1 BtoA_2 dispatch_4 Removed beginning (50 messages) L_ReleaseReg L_ReleaseReq V76frame ( DISC (.1.)) V76frame /* Not yet consumed by */ dispatch_4 waitUAdisc (DISC : (. (1.)) L_ReleaseReq L_ReleaseReq Figure 7.20 End of the error MSC trace We see that process DLC in block DLCa is in state waitUAdisc. If we look at the SDL model, under this state no input or save of signal L_ReleaseReq are specified. Therefore, this signal has been discarded. The discarded L_ReleaseReq signal is shown in Figure 7.20. Exhaustive Simulation 199 7.3.2.2 Correct the error After examining the error, we decide that it is better losing L_ReleaseReq than saving it. Therefore, you will add a dummy input of signal L_ReleaseReq in state waitUAdisc of process A. Exit from the Validator (answering No to the question). B. In Windows (or Unix), make a copy of the file dlc.spr into dlc_v4.spr. C. In 