-
Notifications
You must be signed in to change notification settings - Fork 0
/
cpu-debug-5.html
245 lines (202 loc) · 11.7 KB
/
cpu-debug-5.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>fritzm.github.io - PDP-11/45: CPU debug V -- chasing lights!</title>
<meta name="description" content="">
<meta name="author" content="Fritz Mueller">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!-- Le HTML5 shim, for IE6-8 support of HTML elements -->
<!--[if lt IE 9]>
<script src="https://fritzm.github.io/theme/html5.js"></script>
<![endif]-->
<!-- Le styles -->
<link href="https://fritzm.github.io/theme/bootstrap.min.css" rel="stylesheet">
<link href="https://fritzm.github.io/theme/bootstrap.min.responsive.css" rel="stylesheet">
<link href="https://fritzm.github.io/theme/local.css" rel="stylesheet">
<link href="https://fritzm.github.io/theme/pygments.css" rel="stylesheet">
<!-- Photoswipe -->
<link rel="stylesheet" href="https://fritzm.github.io/theme/photoswipe.css">
<link rel="stylesheet" href="https://fritzm.github.io/theme/default-skin/default-skin.css">
<script src="https://fritzm.github.io/theme/photoswipe.min.js"></script>
<script src="https://fritzm.github.io/theme/photoswipe-ui-default.min.js"></script>
<script src="https://fritzm.github.io/galleries.js"></script>
<script type="text/javascript">
var pswipe = function(gname, index) {
var pswpElement = document.querySelectorAll('.pswp')[0];
var items = galleries[gname];
var options = { index: index };
var gallery = new PhotoSwipe(pswpElement, PhotoSwipeUI_Default, items, options);
gallery.init();
};
</script>
<!-- So Firefox can bookmark->"abo this site" -->
<link href="https://fritzm.github.io/feeds/all.rss.xml" rel="alternate" title="fritzm.github.io" type="application/rss+xml">
</head>
<body>
<div class="navbar">
<div class="navbar-inner">
<div class="container">
<a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</a>
<a class="brand" href="https://fritzm.github.io">fritzm.github.io</a>
<div class="nav-collapse">
<ul class="nav">
</ul>
</div>
</div>
</div>
</div>
<div class="container">
<div class="content">
<div class="row">
<div class="span9">
<div class='article'>
<div class="content-title">
<h1>PDP-11/45: CPU debug V -- chasing lights!</h1>
Sun 19 June 2016
by <a class="url fn" href="https://fritzm.github.io/author/fritz-mueller.html">Fritz Mueller</a>
</div>
<div><p>Tracked down the source of the inverted result after register-to-register move problem on GRA: outputs of the
subsidiary ALU control ROM E74 on pins 6 and 7 are floating. Will need some closer inspection to determine if this
is a board fault or a chip fault. In the meantime, I have a spare GRA which I had been reluctant to try because it
has a "bad" sticker on it... Decided to give it a try anyway, and it seems to be working much better than the one I
have been debugging.</p>
<p>Now have enough of the CPU debugged to toggle in and run a simple light chaser program:</p>
<table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre>1
2
3
4
5
6
7
8</pre></div></td><td class="code"><div class="highlight"><pre><span></span><span class="nt">000000</span> <span class="nt">013700</span> <span class="nt">177570</span> <span class="nt">L0</span><span class="o">:</span> <span class="nt">MOV</span> <span class="o">@</span><span class="p">#</span><span class="nn">177570</span><span class="o">,</span> <span class="nt">R0</span> <span class="o">;</span><span class="nt">LOAD</span> <span class="nt">COUNT</span> <span class="nt">FROM</span> <span class="nt">SWITCH</span> <span class="nt">REGISTER</span>
<span class="nt">000004</span> <span class="nt">005300</span> <span class="nt">L1</span><span class="o">:</span> <span class="nt">DEC</span> <span class="nt">R0</span> <span class="o">;</span><span class="nt">COUNT</span> <span class="nt">DOWN</span>
<span class="nt">000006</span> <span class="nt">001376</span> <span class="nt">BNE</span> <span class="nt">L1</span> <span class="o">;</span><span class="nt">LOOP</span> <span class="nt">UNTIL</span> <span class="nt">ZERO</span>
<span class="nt">000010</span> <span class="nt">006301</span> <span class="nt">ASL</span> <span class="nt">R1</span> <span class="o">;</span><span class="nt">SHIFT</span> <span class="nt">DISPLAY</span> <span class="nt">VALUE</span>
<span class="nt">000012</span> <span class="nt">001002</span> <span class="nt">BNE</span> <span class="nt">L2</span> <span class="o">;</span><span class="nt">SKIP</span> <span class="nt">AHEAD</span> <span class="nt">IF</span> <span class="nt">NOT</span> <span class="nt">SHIFTED</span> <span class="nt">OUT</span>
<span class="nt">000014</span> <span class="nt">012701</span> <span class="nt">000001</span> <span class="nt">MOV</span> <span class="p">#</span><span class="nn">1</span><span class="o">,</span><span class="nt">R1</span> <span class="o">;</span><span class="nt">ELSE</span> <span class="nt">RELOAD</span>
<span class="nt">000020</span> <span class="nt">010137</span> <span class="nt">177570</span> <span class="nt">L2</span><span class="o">:</span> <span class="nt">MOV</span> <span class="nt">R1</span><span class="o">,@</span><span class="p">#</span><span class="nn">177570</span> <span class="o">;</span><span class="nt">STORE</span> <span class="nt">TO</span> <span class="nt">DISPLAY</span> <span class="nt">REGISTER</span>
<span class="nt">000024</span> <span class="nt">000765</span> <span class="nt">BR</span> <span class="nt">L0</span> <span class="o">;</span><span class="nt">REPEAT</span> <span class="nt">FROM</span> <span class="nt">THE</span> <span class="nt">TOP</span>
</pre></div>
</td></tr></table>
<p><span class="videobox">
<iframe width="640" height="390"
src='https://www.youtube.com/embed/ZhuzC9v3q-k?rel=0'
frameborder='0' webkitAllowFullScreen
mozallowfullscreen allowFullScreen>
</iframe>
</span></p>
<p>Some notes on the program and video above since I've received some questions:</p>
<ul>
<li>
<p>The listing here is shown assembled at location 000000, but the program is relocatable and can be toggled in at any
convenient address (000000, on top of the trap vectors, probably isn't the best choice!)</p>
</li>
<li>
<p>Data display should be on "DISPLAY REGISTER" to see the chase.</p>
</li>
<li>
<p>The front panel toggles are loaded into a counter to control the speed of the chase. Without some of the most
significant bits set the chase may go too fast to see, especially on older 11's with incandescent indicators. All
toggles off is a special case: this will be the slowest chase, since as written the counter wraps around when
decremented before being checked for zero. The video has toggles 15 and 14 up.</p>
</li>
<li>
<p>If you look at the address lights in the video, you can see that I ran this program from address 100000. This was
because at the time I had a fault in the first 16KW of memory on my MS11-L so I couldn't execute any code at lower
addresses.</p>
</li>
</ul></div>
<hr>
</div>
</div>
<div class="span3">
<div class="well" style="padding: 8px 0; background-color: #FBFBFB;">
<ul class="nav nav-list">
<li class="nav-header">
Site
</li>
<li><a href="https://fritzm.github.io/archives.html">Archives</a>
<li><a href="https://fritzm.github.io/tags.html">Tags</a>
<li><a href="https://fritzm.github.io/feeds/all.rss.xml" rel="alternate">RSS feed</a></li>
</ul>
</div>
<div class="well" style="padding: 8px 0; background-color: #FBFBFB;">
<ul class="nav nav-list">
<li class="nav-header">
Categories
</li>
<li><a href="https://fritzm.github.io/category/arcade-games.html">Arcade Games</a></li>
<li><a href="https://fritzm.github.io/category/math.html">Math</a></li>
<li><a href="https://fritzm.github.io/category/micros.html">Micros</a></li>
<li><a href="https://fritzm.github.io/category/pdp-11.html">PDP-11</a></li>
<li><a href="https://fritzm.github.io/category/programming.html">Programming</a></li>
<li><a href="https://fritzm.github.io/category/radios.html">Radios</a></li>
</ul>
</div>
<div class="social">
<div class="well" style="padding: 8px 0; background-color: #FBFBFB;">
<ul class="nav nav-list">
<li class="nav-header">
Social
</li>
<li><a href="http://facebook.com/fritzmueller">facebook</a></li>
<li><a href="http://instagram.com/infrafritz">Instagram</a></li>
<li><a href="http://www.linkedin.com/pub/fritz-mueller/a/679/62/">LinkedIn</a></li>
<li><a href="http://jsfiddle.net/user/fritzm/fiddles/">JSFiddle</a></li>
<li><a href="https://github.com/fritzm">GitHub</a></li>
</ul>
</div>
</div>
</div>
</div> </div>
<footer>
<br />
<p><a href="https://fritzm.github.io">fritzm.github.io</a> © Fritz Mueller 2023</p>
</footer>
</div> <!-- /container -->
<!-- Photoswipe -->
<div class="pswp" tabindex="-1" role="dialog" aria-hidden="true">
<div class="pswp__bg"></div>
<div class="pswp__scroll-wrap">
<div class="pswp__container">
<div class="pswp__item"></div>
<div class="pswp__item"></div>
<div class="pswp__item"></div>
</div>
<div class="pswp__ui pswp__ui--hidden">
<div class="pswp__top-bar">
<div class="pswp__counter"></div>
<button class="pswp__button pswp__button--close" title="Close (Esc)"></button>
<button class="pswp__button pswp__button--share" title="Share"></button>
<button class="pswp__button pswp__button--fs" title="Toggle fullscreen"></button>
<button class="pswp__button pswp__button--zoom" title="Zoom in/out"></button>
<div class="pswp__preloader">
<div class="pswp__preloader__icn">
<div class="pswp__preloader__cut">
<div class="pswp__preloader__donut"></div>
</div>
</div>
</div>
</div>
<div class="pswp__share-modal pswp__share-modal--hidden pswp__single-tap">
<div class="pswp__share-tooltip"></div>
</div>
<button class="pswp__button pswp__button--arrow--left" title="Previous (arrow left)">
</button>
<button class="pswp__button pswp__button--arrow--right" title="Next (arrow right)">
</button>
<div class="pswp__caption">
<div class="pswp__caption__center"></div>
</div>
</div>
</div>
</div>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script src="https://fritzm.github.io/theme/bootstrap-collapse.js"></script>
</body>
</html>