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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Thanks, we were just discussing the same workaround here:<o:p></o:p></span></p>
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color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">To use a message que, and then let the interrupt handlers or whatever send a short message containing message type and optional data.<o:p></o:p></span></p>
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color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Wingdings;
color:#1F497D">J</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">That will require manual modification of approx. 25 source files, so it is possible. The original idea was just to replace the OS wrapper, but the footprint
seems too different.<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:
"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;
font-family:"Tahoma","sans-serif""> Peter Dufault [mailto:dufault@hda.com]
<br>
<b>Sent:</b> 29. november 2011 15:50<br>
<b>To:</b> Mogens Dybęk Christensen<br>
<b>Cc:</b> rtems-users@rtems.org<br>
<b>Subject:</b> Re: Waiting for multiple events<o:p></o:p></span></p>
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<p class="MsoNormal">On Nov 29, 2011, at 9:18 , Mogens Dybęk Christensen wrote:<o:p></o:p></p>
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<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">We are about to port code from the RTXC OS to RTEMS. Several modules use a pattern, where a task is waiting for one of several things to happen. Can be timer, semaphore(s)
or queue. The current wrapper implementation uses a semaphore _<i>list</i>_ function in RTXC, which has no direct counterpart in RTEMS.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<pre><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">The wanted function is similar to select(). (WaitForMultipleObjects() on Windows is another example.) The FAQ on the wiki mentions RTEMS event as a good alternative. </span><o:p></o:p></pre>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">So, the solution could be, that a semaphore or queue is signalled, e.g. from interrupt, and a small helper task waiting at that semaphore/queue will translate to an RTEMS
event for the appropriate task. Then the task will check the event mask to see who called, and read from the queue if needed.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Has anyone done something similar? I am not really happy with the extra helper tasks. <span class="apple-converted-space"> </span></span><span style="font-size:11.0pt;font-family:Wingdings">J</span><span style="font-size:
11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">But they may be necessary if there is no simple way for the interrupt handler to know the receiving task and its local event encoding.<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">You may need to explain this to me further. Do you mean you want to avoid a helper task per event that then posts to a single handler task? Can the single handler task wait at a message queue with small fixed size messages and can the
various interrupts post a cookie to that message queue? The cookie could be a bit mask of some sort, or even be the function that the task should invoke, though you can hide that in the implementation.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">See mq_open(), mq_send(), mq_receive(), mq_close().<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span class="apple-style-span"><span style="font-size:9.0pt;
font-family:"Helvetica","sans-serif";color:black">Peter</span></span><span style="font-size:9.0pt;font-family:"Helvetica","sans-serif";color:black"><br>
<span class="apple-style-span">-----------------</span><br>
<span class="apple-style-span">Peter Dufault</span><br>
<span class="apple-style-span">HD Associates, Inc. Software and System Engineering</span></span><span style="font-size:13.5pt;font-family:
"Helvetica","sans-serif";color:black"><o:p></o:p></span></p>
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