 | | Re: RCX Programming Questions and Sensor Ideas —Kekoa Proudfoot
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| | | (...) This assumes that the check and the set are, together, atomic. Does the SDK document describe what if/why this might be atomic? I haven't had a chance to read it in enough detail to find this answer for myself. -Kekoa (26 years ago, 10-Nov-98, to lugnet.robotics)
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| | | | | Re: RCX Programming Questions and Sensor Ideas —Joshua Delahunty
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| | | | | (...) ...and it would be my sincerest recommendation that you NOT read it, Kekoa. It would be safer from the reverse-engineering standpoint that you NOT use this SDK in any manner. *I* can read it, though <g>, and I can find nothing that indicates a (...) (26 years ago, 10-Nov-98, to lugnet.robotics)
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| | | | | | | Re: RCX Programming Questions and Sensor Ideas —Paul Haas
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| | | | | | | (...) Check and set do not have to be atomic, they have to be ordered. The sequence is: Check all flags, when clear, set our flag, check all flags again, if only ours is set, do stuff. 1. You can dedicate a task to managing semaphores. I described (...) (26 years ago, 11-Nov-98, to lugnet.robotics)
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| | | | | | | | | Re: RCX Programming Questions and Sensor Ideas —Ben Laurie
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| | | | | | | | (...) It isn't guaranteed to work, either, though it is likely to in the end. This is because two processes can conspire to always have r31 == 2 when you test for r31 == 1. Cheers, Ben. (26 years ago, 11-Nov-98, to lugnet.robotics)
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| | | | | | | | | | Re: RCX Programming Questions and Sensor Ideas —Paul Haas
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| | | | | | | | (...) Oops. I don't know how the scheduler in the RCX works. It might execute 1 opcode from each task in order. If 2 tasks get in sync, then they will never leave the semaphore code as written. Here's a fixed version. I added a random backoff. (...) (...) (26 years ago, 11-Nov-98, to lugnet.robotics)
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| | | | | | | | | | Re: RCX Programming Questions and Sensor Ideas —Todd Lehman
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| | | | | | | | (...) Paul, Are you sure you want to sleep before decrementing r31? As written, r31 is always >= 1 during the sleep -- which prevents any other tasks from obtaining a lock on the resource during this sleep time. In other words, once any two tasks (...) (26 years ago, 11-Nov-98, to lugnet.robotics)
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| | | | | | | | | | Re: RCX Programming Questions and Sensor Ideas —Paul Haas
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| | | | | | | | (...) I think "oops" applies in this case. Your fix looks correct. (...) It doesn't have to be random, just each task needs a different delay. This is easy, since each task has to run its own version of the code. For task 3 insert 3 noops, for task (...) (26 years ago, 11-Nov-98, to lugnet.robotics)
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| | | | | | | | | | Re: RCX Programming Questions and Sensor Ideas —Todd Lehman
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| | | | | | | | (...) Does that support an arbitrary number of tasks? If there are n tasks numbered 1 to n, and task k delays for k cycles on failure, I think you still have to be careful to make sure that the number of tasks n is smaller than the loop overhead h (...) (26 years ago, 11-Nov-98, to lugnet.robotics)
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| | | | | | | Re: RCX Programming Questions and Sensor Ideas —CyberUser
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| | | | | | In message <3648D155.FF4306@alu...ucsc.edu>, Joshua Delahunty <lugnet.robotics@lugnet.com> writes (...) RECEIVED is spelt wrong in the Spirit.OCX software too. :-) I would like to add though that I was impressed with the high quality of the manual. (26 years ago, 11-Nov-98, to lugnet.robotics)
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| | | | | Re: RCX Programming Questions and Sensor Ideas —Peter Hesketh
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| | | | In article <199811102221.OAA071...ford.EDU>, Kekoa Proudfoot <kekoa@Graphics.Stanford.EDU> quotes and writes (...) You are right, of course. (...) If it does I haven't found it. (26 years ago, 11-Nov-98, to lugnet.robotics)
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