root/branches/maintenance/3.0/Modelica/Electrical/Digital.mo

Revision 1159, 171.9 kB (checked in by dietmarw, 2 months ago)

fixes #100 (in maintenance/3.0) by changing the annotation to a vendor specific annotation

From: Dietmar Winkler <Dietmar.Winkler@…>
  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
Line 
1within Modelica.Electrical;
2package Digital
3  "Library for digital electrical components based on the VHDL standard with 9-valued logic and conversion to 2-,3-,4-valued logic"
4package UsersGuide "User's Guide"
5
6  annotation (__Dymola_DocumentationClass=true, Documentation(info="<html>
7<p>
8Library <b>Electrical.Digital</b> is a <b>free</b> Modelica package providing
9components to model <b>digital</b> electronic
10systems based on combinational and sequential logic in a convenient
11way. This package contains the <b>User's Guide</b> for
12the library and has the following content:
13</p>
14<ol>
15<li><a href=\"Modelica://Modelica.Electrical.Digital.UsersGuide.OverView\">Overview of library</a>
16     gives an overview of the library.</li>
17<li> <a href=\"Modelica://Modelica.Electrical.Digital.UsersGuide.FirstExample\">A first example</a>
18     demonstrates at hand of a first example how to use this library.</li>
19<li> <a href=\"Modelica://Modelica.Electrical.Digital.UsersGuide.ApplicationExample\">An
20     application example</a> demonstrates a generic n-bit adder.
21     .</li>
22<li><a href=\"Modelica://Modelica.Electrical.Digital.UsersGuide.ReleaseNotes\">Release Notes</a>
23    summarizes the differences between different versions of this library.</li>
24<li><a href=\"Modelica://Modelica.Electrical.Digital.UsersGuide.Literature\">Literature</a>
25    provides references that have been used to design and implement this
26    library.</li>
27<li><a href=\"Modelica://Modelica.Electrical.Digital.UsersGuide.Contact\">Contact</a>
28    provides information about the authors of the library as well as
29    acknowledgments.</li>
30</ol>
31</html>"));
32
33  class OverView "Overview of library"
34
35    annotation (Documentation(info="<html>
36<p>
37In this section, an overview of the most important features
38of this library is given.
39</p>
40<p>(will be added as soon as possible). </p>
41</html>
42"));
43  end OverView;
44
45  class FirstExample "A first example"
46
47    annotation (Documentation(info="<html>
48<p>
49A first example will be given here (not yet done).
50</p>
51</html>
52"));
53  end FirstExample;
54
55  class ApplicationExample "An application example"
56
57    annotation (Documentation(info="<html>
58<p>
59An application example will be given here (not yet done).
60</p>
61</html>
62"));
63  end ApplicationExample;
64
65  class ReleaseNotes "Release notes"
66
67    annotation (Documentation(info="<html>
68<h4>Version 1.0.7, 2005-07-01</h4>
69<ul>
70<li> xxxx</li>
71</ul>
72<h4>Version 1.0.6, 2004-10-18</h4>
73<ul>
74<li> Missing HTML tags added (problems with mismatched pre tags fixed).</li>
75<li> CVS ID string deleted.</li>
76</ul>
77<h4>Version 1.0.5, 2004-10-01</h4>
78<ul>
79<li> Wrong identifiers x0 and Tdel in HalfAdder example fixed.</li>
80<li> Experiment command in FlipFlop example deleted.</li>
81<li> Known issue: Pulse source causes a warning in Dymola. It is recommended to use Clock source.</li>
82</ul>
83<h4>Version 1.0.4, 2004-09-30</h4>
84<ul>
85<li> Documentation improved.</li>
86</ul>
87<h4>Version 1.0.3, 2004-09-21</h4>
88<ul>
89<li> Table names changed from \"map\" to \"Table\".</li>
90<li> Icons for converters modified.</li>
91<li> LogicValueType renamed to Logic. For the Electrical.Digital library
92     the type Logic has a fundamental meaning. Logic is similar to
93     Real, Integer or Boolean in other packages. Names for converters
94     are now more consistent (LogicToBoolean, RealToLogic etc.).</li>
95<li> Icons for gates and sources improved.</li>
96<li> New examples added.</li>
97<li> Internal names for signals and ports unified.</li>
98<li> Simple Clock source added in addition to Pulse source (for convenience reasons).</li>
99</ul>
100<h4>Version 1.0.2, 2004-09-13</h4>
101<ul>
102<li> First prerelease for discussions at the 40th Modelica Design Meeting.</li>
103</ul>
104<h4>Version 1.0.1, 2004-06-01</h4>
105<ul>
106<li> Packages Tables, Basic, and Gates implemented.</li>
107<li> Transport and inertial delay implemented and successfully tested.</li>
108</ul>
109<h4>Version 1.0.0, 2003-05-01</h4>
110<ul>
111<li> A first version has been implemented for case studies.</li>
112</ul>
113</html>
114"));
115  equation
116
117  end ReleaseNotes;
118
119  class Literature "Literature"
120
121    annotation (Documentation(info="<html>
122<p>
123The Electrical.Digital library is based on the following references:
124</p>
125<dl>
126<dt>Ashenden, P. J.:</dt>
127<dd> <b>The Designer's Guide to VHDL.</b> San Francisco: Morgan Kaufmann, 1995, 688 p. ISBN 1-55860-270-4.
128     <br>&nbsp;</dd>
129</dl>
130<dl>
131<dt>IEEE 1076-1993:</dt>
132<dd> <b>IEEE Standard VHDL Language Reference Manual (ANSI).</b> 288 p. ISBN 1-55937-376-8. IEEE Ref. SH16840-NYF.
133     <br>&nbsp;</dd>
134</dl>
135<dl>
136<dt>IEEE 1164-1993:</dt>
137<dd> <b>IEEE Standard Multivalue Logic System for VHDL Model Interoperability (Std_logic_1164).</b> 24 p. ISBN 1-55937-299-0. IEEE Ref. SH16097-NYF.
138     <br>&nbsp;</dd>
139</dl>
140<dl>
141<dt>Lipsett, R.; Schaefer, C.; Ussery, C.:</dt>
142<dd> <b>VHDL: Hardware Description and Design.</b> Boston: Kluwer, 1989, 299 p. ISBN 079239030X.
143     <br>&nbsp;</dd>
144</dl>
145<dl>
146<dt>Navabi, Z:</dt>
147<dd> <b>VHDL: Analysis and Modeling of Digital Systems.</b> New York: McGraw-Hill, 1993, 375 p. ISBN 0070464723.
148     <br>&nbsp;</dd>
149</dl>
150</html>
151 "));
152
153  end Literature;
154
155  class Contact "Contact"
156
157    annotation (Documentation(info="<html>
158<dl>
159<dt><b>Main Authors:</b>
160<dd><a href=\"http://people.eas.iis.fraunhofer.de/Christoph.Clauss/\">Christoph Clau&szlig;</a>
161    &lt;<A HREF=\"mailto:Christoph.Clauss@eas.iis.fraunhofer.de\">Christoph.Clauss@eas.iis.fraunhofer.de</A>&gt;<br>
162    <a href=\"http://people.eas.iis.fraunhofer.de/Andre.Schneider/\">Andr&eacute; Schneider</a>
163    &lt;<A HREF=\"mailto:Andre.Schneider@eas.iis.fraunhofer.de\">Andre.Schneider@eas.iis.fraunhofer.de</A>&gt;<br>
164    Fraunhofer Institute for Integrated Circuits (IIS)<br>
165    Design Automation Department (EAS)<br>
166    Zeunerstra&szlig;e 38<br>
167    D-01069 Dresden<br>
168    Germany<br>
169</dl>
170<br>
171<br>
172<dl>
173<dt><b>Acknowledgements:</b></dt>
174<dd>
175    We thank our colleague <a href=\"http://people.eas.iis.fraunhofer.de/Ulrich.Donath/\">Ulrich Donath</a>
176    &lt;<a href=\"mailto:Ulrich.Donath@eas.iis.fraunhofer.de\">Ulrich.Donath@eas.iis.fraunhofer.de</a>&gt;
177    for his support and fruitful discussions regarding all questions on VHDL and the IEEE 1164 standard
178    logic libraries. Furthermore, we thank our students Teresa Schlegel and Enrico Weber for implementing
179    and carefully testing many models and examples.<br>
180</dd>
181</dl>
182</html>
183"));
184
185  end Contact;
186
187end UsersGuide;
188
189  annotation (
190   
191    Documentation(info="<html>
192<p>
193This library contains packages for digital electrical components. Both, type system
194and models are based on the VHDL standard (IEEE Std 1076-1987 VHDL, IEEE Std 1076-1993 VHDL,
195IEEE Std 1164 Multivalue Logic System):
196<ul>
197<li>Interfaces: Definition of signals and interfaces</li>
198<li>Tables: All truth tables needed</li>
199<li>Delay: Transport and inertial delay</li>
200<li>Basic: Basic logic without delay</li>
201<li>Gates: Basic gates composed by basic components and inertial delay</li>
202<li>Tristate: (not yet available)</li>
203<li>FlipFlops: (not yet available) </li>
204<li>Latches: (not yet available)</li>
205<li>TransferGates: (not yet available)</li>
206<li>Multiplexers (not yet available)</li>
207<li>Memory: Ram, Rom, (not yet available)</li>
208<li>Sources: Time-dependend signal sources</li>
209<li>Converters</li>
210<li>Examples</li>
211</ul>
212</p>
213<p>
214The logic values are coded by integer values. The following code table is necessary
215for both setting of input and interpreting the output values.
216</p>
217<p><b>Code Table:</b></p>
218 
219<table border=1 cellspacing=0 cellpadding=2>
220  <tr><td valign=\"top\"><b>Logic value</b></td>
221      <td valign=\"top\"><b>Integer code</b></td>
222      <td valign=\"top\"><b>Meaning</b></td>
223  </tr>
224                         
225  <tr><td valign=\"top\">'U'</td> <td valign=\"top\">1</td> <td valign=\"top\">Uninitialized</td></tr>
226  <tr><td valign=\"top\">'X'</td> <td valign=\"top\">2</td> <td valign=\"top\">Forcing Unknown</td></tr>
227  <tr><td valign=\"top\">'0'</td> <td valign=\"top\">3</td> <td valign=\"top\">Forcing 0</td></tr>
228  <tr><td valign=\"top\">'1'</td> <td valign=\"top\">4</td> <td valign=\"top\">Forcing 1</td></tr>
229  <tr><td valign=\"top\">'Z'</td> <td valign=\"top\">5</td> <td valign=\"top\">High Impedance</td></tr>
230  <tr><td valign=\"top\">'W'</td> <td valign=\"top\">6</td> <td valign=\"top\">Weak Unknown</td></tr>
231  <tr><td valign=\"top\">'L'</td> <td valign=\"top\">7</td> <td valign=\"top\">Weak 0</td></tr>
232  <tr><td valign=\"top\">'H'</td> <td valign=\"top\">8</td> <td valign=\"top\">Weak 1</td></tr>
233  <tr><td valign=\"top\">'-'</td> <td valign=\"top\">9</td> <td valign=\"top\">Don't care</td></tr>
234</table>
235 
236<p>
237The library will be developed in two main steps. The first step contains the basic components and
238the gates. In the next step the more complicated devices will be added. Currently the first step of
239the library is implemented and released for public use.
240</p>
241 
242<p>
243Copyright &copy; 1998-2008, Modelica Association and Fraunhofer-Gesellschaft.
244</p>
245<p>
246<i>This Modelica package is <b>free</b> software; it can be redistributed and/or modified
247under the terms of the <b>Modelica license</b>, see the license conditions
248and the accompanying <b>disclaimer</b> 
249<a href=\"Modelica://Modelica.UsersGuide.ModelicaLicense\">here</a>.</i>
250</p><br>
251 
252</HTML>
253"), Diagram(coordinateSystem(
254        preserveAspectRatio=true,
255        extent={{-100,-100},{100,100}},
256        grid={2,2}), graphics),
257    Icon(coordinateSystem(
258        preserveAspectRatio=true,
259        extent={{-100,-100},{100,100}},
260        grid={2,2}), graphics={
261        Polygon(
262          points={{-100,-100},{-100,50},{80,50},{80,-100},{-100,-100}},
263          fillColor={235,235,235},
264          fillPattern=FillPattern.Solid,
265          lineColor={0,0,255}),
266        Polygon(
267          points={{-100,50},{-80,70},{100,70},{80,50},{-100,50}},
268          fillColor={235,235,235},
269          fillPattern=FillPattern.Solid,
270          lineColor={0,0,255}),
271        Polygon(
272          points={{100,70},{100,-80},{80,-100},{80,50},{100,70}},
273          fillColor={235,235,235},
274          fillPattern=FillPattern.Solid,
275          lineColor={0,0,255}),
276        Text(
277          extent={{-120,122},{120,73}},
278          lineColor={255,0,0},
279          textString="%name"),
280        Rectangle(
281          extent={{-52,4},{-32,-36}},
282          lineColor={0,0,0},
283          fillColor={255,255,255},
284          fillPattern=FillPattern.Solid),
285        Rectangle(
286          extent={{8,-46},{28,-86}},
287          lineColor={0,0,0},
288          fillColor={255,255,255},
289          fillPattern=FillPattern.Solid),
290        Rectangle(
291          extent={{8,4},{28,-36}},
292          lineColor={0,0,0},
293          fillColor={255,255,255},
294          fillPattern=FillPattern.Solid),
295        Line(points={{-72,-6},{-52,-6}}, color={0,0,0}),
296        Line(points={{-72,-28},{-52,-28}}, color={0,0,0}),
297        Ellipse(extent={{-32,-14},{-28,-18}}, lineColor={0,0,0}),
298        Ellipse(extent={{28,-14},{32,-18}}, lineColor={0,0,0}),
299        Line(points={{-28,-16},{8,-16}}, color={0,0,0}),
300        Line(points={{-28,-16},{-12,-16},{-12,-56},{8,-56}}, color={0,0,0}),
301        Line(points={{8,-76},{-72,-76}}, color={0,0,0}),
302        Line(points={{32,-16},{48,-16}}, color={0,0,0}),
303        Line(points={{28,-66},{48,-66}}, color={0,0,0}),
304        Text(
305          extent={{-32,-8},{-52,0}},
306          lineColor={0,0,0},
307          textString="&"),
308        Text(
309          extent={{28,-10},{8,-2}},
310          lineColor={0,0,0},
311          textString="1"),
312        Text(
313          extent={{28,-58},{8,-50}},
314          lineColor={0,0,0},
315          textString="="),
316        Text(
317          extent={{-90,40},{70,10}},
318          lineColor={160,160,164},
319          fillColor={0,0,0},
320          fillPattern=FillPattern.Solid,
321          textString="Library")}));
322
323  package Examples
324    "Examples that demonstrate the usage of the Digital electrical components"
325    model Multiplexer "4 to 1 Bit Multiplexer Example"
326      import D = Modelica.Electrical.Digital;
327      import L = Modelica.Electrical.Digital.Interfaces.Logic;
328      annotation (
329        Documentation(info="<HTML>
330<h4>4 to 1 Bit Multiplexer</h4>
331<P>
332The multiplexer converts a parallel 4 bit signal in a sequential
3331 bit stream.
334</P>
335</HTML>
336"),     Icon(coordinateSystem(
337            preserveAspectRatio=true,
338            extent={{-100,-100},{100,100}},
339            grid={2,2}), graphics={Rectangle(
340              extent={{-100,100},{100,-100}},
341              lineColor={0,0,0},
342              lineThickness=0.5,
343              fillColor={255,255,170},
344              fillPattern=FillPattern.Solid)}),
345        Diagram(coordinateSystem(
346            preserveAspectRatio=true,
347            extent={{-100,-100},{100,100}},
348            grid={2,2}), graphics)
349        ,
350        experiment(StopTime=250));
351      D.Sources.Clock CLK(period=20)  annotation (Placement(transformation(
352              extent={{-80,-56},{-60,-36}}, rotation=0)));
353      D.Sources.Table D0(
354        y0=3,
355        x={4,3,4,3},
356        t={50,100,145,200}) annotation (Placement(transformation(extent={{-80,
357                58},{-60,78}}, rotation=0)));
358      D.Sources.Table D1(
359        y0=3,
360        x={4,3,4,3},
361        t={22,140,150,180}) annotation (Placement(transformation(extent={{-80,
362                32},{-60,52}}, rotation=0)));
363      D.Examples.Utilities.MUX4 MUX annotation (Placement(transformation(extent=
364               {{-10,0},{70,80}}, rotation=0)));
365      D.Sources.Table D2(
366        y0=3,
367        x={4,3,4,3},
368        t={22,140,150,180}) annotation (Placement(transformation(extent={{-80,6},
369                {-60,26}}, rotation=0)));
370      D.Sources.Table D3(
371        y0=3,
372        x={4,3,4,3},
373        t={22,140,150,180}) annotation (Placement(transformation(extent={{-80,
374                -20},{-60,0}}, rotation=0)));
375      D.Examples.Utilities.JKFF FF annotation (Placement(transformation(extent=
376                {{-20,-62},{0,-42}}, rotation=0)));
377      D.Sources.Set Enable annotation (Placement(transformation(extent={{-80,
378                -82},{-60,-62}}, rotation=0)));
379    equation
380      connect(CLK.y, FF.clk) annotation (Line(
381          points={{-60,-46},{-36,-46},{-36,-52},{-20,-52}},
382          color={127,0,127}));
383      connect(Enable.y, FF.k) annotation (Line(
384          points={{-60,-72},{-30,-72},{-30,-59},{-20,-59}},
385          color={127,0,127}));
386      connect(Enable.y, FF.j) annotation (Line(
387          points={{-60,-72},{-30,-72},{-30,-45},{-20,-45}},
388          color={127,0,127}));
389      connect(CLK.y, MUX.a0) annotation (Line(
390          points={{-60,-46},{-36,-46},{-36,22.4},{-10,22.4}},
391          color={127,0,127}));
392      connect(D0.y, MUX.d0) annotation (Line(
393          points={{-60,68},{-10,68}},
394          color={127,0,127}));
395      connect(D1.y, MUX.d1) annotation (Line(
396          points={{-60,42},{-54,42},{-54,57.6},{-10,57.6}},
397          color={127,0,127}));
398      connect(D2.y, MUX.d2) annotation (Line(
399          points={{-60,16},{-50,16},{-50,47.2},{-10,47.2}},
400          color={127,0,127}));
401      connect(D3.y, MUX.d3) annotation (Line(
402          points={{-60,-10},{-46,-10},{-46,36.8},{-10,36.8}},
403          color={127,0,127}));
404      connect(FF.q, MUX.a1) annotation (Line(
405          points={{0,-45},{2,-45},{2,-22},{-20,-22},{-20,12},{-10,12}},
406          color={127,0,127}));
407    end Multiplexer;
408
409    model FlipFlop "Pulse Triggered Master Slave Flip-Flop"
410      import D = Modelica.Electrical.Digital;
411      import L = Modelica.Electrical.Digital.Interfaces.Logic;
412      annotation (
413        Documentation(info="<HTML>
414<h4>FlipFlop</h4>
415<P>
416Pulse-triggered master-slave flip-flop.
417</P>
418</HTML>
419"),     Icon(coordinateSystem(
420            preserveAspectRatio=true,
421            extent={{-100,-100},{100,100}},
422            grid={2,2}), graphics={Rectangle(
423              extent={{-100,100},{100,-100}},
424              lineColor={0,0,0},
425              lineThickness=0.5,
426              fillColor={255,255,170},
427              fillPattern=FillPattern.Solid)}),
428        Diagram(coordinateSystem(
429            preserveAspectRatio=true,
430            extent={{-100,-100},{100,100}},
431            grid={2,2}), graphics)
432        ,
433        experiment(StopTime=250));
434      D.Examples.Utilities.JKFF FF
435                     annotation (Placement(transformation(extent={{-10,-40},{70,
436                40}}, rotation=0)));
437      D.Sources.Clock CLK(period=10)  annotation (Placement(transformation(
438              extent={{-80,-10},{-60,10}}, rotation=0)));
439      D.Sources.Table J(
440        y0=3,
441        x={4,3,4,3},
442        t={50,100,145,200}) annotation (Placement(transformation(extent={{-80,
443                18},{-60,38}}, rotation=0)));
444      D.Sources.Table K(
445        y0=3,
446        x={4,3,4,3},
447        t={22,140,150,180}) annotation (Placement(transformation(extent={{-80,
448                -38},{-60,-18}}, rotation=0)));
449    equation
450      connect(J.y, FF.j)     annotation (Line(
451          points={{-60,28},{-10,28}},
452          color={127,0,127}));
453      connect(CLK.y, FF.clk)    annotation (Line(
454          points={{-60,0},{-10,0}},
455          color={127,0,127}));
456      connect(K.y, FF.k)      annotation (Line(
457          points={{-60,-28},{-10,-28}},
458          color={127,0,127}));
459    end FlipFlop;
460
461    model HalfAdder "adding circuit for binary numbers without input carry bit"
462      import Modelica.Electrical.Digital;
463      annotation (
464        Documentation(info="<HTML>
465<P>
466This example demonstrates an adding circuit for binary numbers, which internally realizes the interconnection to
467And and to Xor in the final sum.
468<br>
469<br>
4701 + 0 = 1<br>
4710 + 1 = 1<br>
4721 + 1 = 10<br>
4730 + 0 = 0
474<br>
475<br>
476<b>a</b> + <b>b</b> = <b>s</b>
477<br>(The carry of this adding is <b>c</b>.)
478<br>
479<br>and
480<br>
481<br>
482<b>a</b> * <b>b</b> = <b>s</b>
483<br>  (It is an interconnection to And.)
484<br>
485<br>
486<b>a</b> * <b>b</b> + <b>a</b> * <b>b</b> = <b>a</b> Xor <b>b</b> = <b>c</b>
487<br>(It is an interconnection to Xor.)
488<br>
489<br>
490<pre>  <b>a</b>     <b>b</b>     <b>c</b>      <b>s</b>     <b>t</b></pre>
491 
492 <pre>  1     0     1      0     1</pre>
493 <pre>  0     1     1      0     2</pre>
494 <pre>  1     1     0      1     3</pre>
495 <pre>  0     0     0      0     4</pre>
496 
497<br>
498<br>
499<b>t</b> is the pick-up instant of the next bit(s) in the simulation.
500The simulation stop time should be 5 seconds.
501</P>
502</HTML>
503"),     Icon(coordinateSystem(
504            preserveAspectRatio=true,
505            extent={{-100,-100},{100,100}},
506            grid={2,2}), graphics={Rectangle(
507              extent={{-88,100},{90,-100}},
508              lineColor={0,0,0},
509              lineThickness=0.5,
510              fillColor={255,255,170},
511              fillPattern=FillPattern.Solid), Line(points={{40,54},{40,60},{-40,
512                  60},{10,0},{-40,-60},{40,-60},{40,-52}}, color={0,0,0})}),
513        Diagram(coordinateSystem(
514            preserveAspectRatio=true,
515            extent={{-100,-100},{100,100}},
516            grid={2,2}), graphics)
517        ,
518        experiment(StopTime=5));
519
520      Sources.Table a(
521        t={1,2,3,4},
522        x={4,3,4,3},
523        y0=3)   annotation (Placement(transformation(extent={{-80,18},{-60,38}},
524              rotation=0)));
525      Sources.Table b(
526        x={4,3},
527        t={2,4},
528        y0=3)   annotation (Placement(transformation(extent={{-80,-38},{-60,-18}},
529              rotation=0)));
530      Digital.Examples.Utilities.HalfAdder Adder(delayTime=0.3) 
531                            annotation (Placement(transformation(extent={{-40,
532                -40},{40,40}}, rotation=0)));
533      Digital.Converters.LogicToReal s
534                               annotation (Placement(transformation(extent={{60,
535                18},{80,38}}, rotation=0)));
536      Digital.Converters.LogicToReal c
537                               annotation (Placement(transformation(extent={{60,
538                -38},{80,-18}}, rotation=0)));
539    equation
540      connect(b.y,Adder. b) annotation (Line(
541          points={{-60,-28},{-40,-28}},
542          color={127,0,127}));
543      connect(a.y,Adder. a) annotation (Line(
544          points={{-60,28},{-40,28}},
545          color={127,0,127}));
546      connect(Adder.s, s.x[1]) annotation (Line(points={{40,28},{65,28}}, color=
547             {127,0,127}));
548      connect(Adder.c, c.x[1]) annotation (Line(points={{40,-28},{65,-28}},
549            color={127,0,127}));
550    end HalfAdder;
551
552    model FullAdder "Full 1 Bit Adder Example"
553      import D = Modelica.Electrical.Digital;
554      import L = Modelica.Electrical.Digital.Interfaces.Logic;
555      annotation (
556        Documentation(info="<HTML>
557<P>
558<br>It is an adding circuit for binary numbers with input carry bit, which consists of two HalfAdders.
559<br>
560<br>
561<b>a</b>