On-line Debugging Tool

<h2 id="console-odt">Console ODT</h2>
<p>Console ODT<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a> replaces the "lights and switches" console of many of the earlier processors.
</p><p>Access to console ODT is obtained either from power up (with appropriate power up mode selected), by the execution of a HALT instruction in kernel mode, or by use of the front panel halt switch or button.
</p>
<h2 id="example">Example</h2>
@1000/ xxxxxx 112737<LF>
001002 xxxxxx 101<LF>
001004 xxxxxx 177566<LF>
001006 xxxxxx 137<LF>
001010 xxxxxx 1000<CR>
>R7/xxxxxx 1000<CR>
>RS/340

<p>This deposits the program
</p>
 MOVB 'A', @#177566  ; Move 'A' into console transmit register
 JMP @#1000        ; Jump back to start

<p>The deposit to the PC [Program Counter], sets the PC to the start of the program and the deposit to the PSW [Program Status Word] locks out interrupts.
</p><p>The effect of this will be to write a stream of "A" to the console. As there is no check for transmitter ready, it is highly probable that a large number of garbage characters will be displayed.
</p>
<h2 id="rsx-11m-plus-odt">RSX-11M-Plus ODT</h2>
<p>The RSX-11M-Plus ODT<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> is essentially a superset of all other ODT implementations.
</p><p>ODT is implemented as code that is linked with a task using the Task Builder /DA switch.
</p>
TKB HELLO/DA,HELLO/CR=HELLO

<p>Once any task built with ODT is run ODT is invoked on entry.
</p>
RUN HELLO
ODT:TT0
_

<p>The underscore is the standard ODT prompt.
</p><p>Addresses in the ODT debugger are 16-bit addresses in the mode in which ODT is operating, not the physical addresses used with console ODT.
</p>
<h2 id="os8-octal-debugging-technique">OS/8 Octal Debugging Technique</h2>
<p>The <a href="/facts/PDP-8/udvrynE8">PDP-8</a>'s <a href="/facts/OS%2f8/tentXljI">OS/8</a> operating system's ODT command<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> invokes its <i>Octal Debugging Technique</i> tool.
</p><p>As with the subsequent PDP-11 ODT programs, it is non-symbolic, and it can examine or modify memory, and also set breakpoints.
</p>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Dynamic_Debugging_Technique/jmRMJtmj">Dynamic Debugging Technique</a> (DDT)</li>
<li>Executive Debugging Technique (XDT)</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>p192-202 PDP-11 Processor Handbook: pdp11/04/24/34a/44/70, Digital, 1981 <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>IAS/RSX-11 ODT Reference Manual, Order Number AA-M507A-TC, Digital, 1982 <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Reference manual DEC-D8-COCO-D, ODT-8, Dec. 1967 "DEC-D8-COCO-D ODT.pdf" (PDF). BitSavers.org. <a href="http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/DEC-D8-COCO-D%20ODT-8.pdf" target="_blank">http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/DEC-D8-COCO-D%20ODT-8.pdf</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
</ol>

On-line Debugging Tool open-in-new

On-line Debugging Tool