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31 lines
1.3 KiB
Plaintext
Executable File
31 lines
1.3 KiB
Plaintext
Executable File
Copyright (c) 1999 Massachusetts Institute of Technology
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See the COPYING file at the top-level directory of this project.
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------------------------------
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Date: Sat, 14 Jul 84 02:43 EDT
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From: David A. Moon <Moon at SCRC-STONY-BROOK.ARPA>
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To: alan at MIT-MC.ARPA
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cc: bug-its at MIT-MC.ARPA
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Re: ITS seemed to be looping
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Things to try:
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Raise switch 0 (the switch 0 on the left). If this goes to DDT, it's
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taking clock interrupts.
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Hit Break and type PC <return>. If I remember correctly, you can read
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the PC this way without halting the machine. There are some other status-type
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commands; PCF is the PC flags, PI is the interrupt status.
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Hit Break and type SP <return>. This stops the machine cleanly (between
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instructions). If this works, the microcode isn't looping. Now you can
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get the PC then type DDT (or ST 774000) to get into DDT and decode that PC.
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If the microcode is looping the SM command will restart it. This also does
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nasty things like resetting the I/O bus. I think it preserves the PC though.
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There is a command file, J KLHUNG, which prints out everything in sight. 90%
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of what it prints is worthless, but it includes micro and macro PCs.
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I believe there is a piece of paper taped to the machine that tells you to
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do J KLHUNG. Of course there are a lot of pieces of paper taped to the machine!
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