doc/latexfiles/tut1.tex

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% Magic tutorial number 1
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\def\mytitle{Magic Tutorial \#1: Getting Started}

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\begin{center}
  {\bfseries \Large \mytitle} \\
  \vspace*{0.5in}
  {\itshape John Ousterhout} \\
  \vspace*{0.5in}
   Computer Science Division \\
   Electrical Engineering and Computer Sciences \\
   University of California \\
   Berkeley, CA  94720 \\
  \vspace*{0.25in}
  {\itshape (Updated by others, too.)} \\
  \vspace*{0.25in}
  This tutorial corresponds to Magic version 7. \\
\end{center}
\vspace*{0.5in}

\section{What is Magic?}

Magic is an interactive system for creating and modifying
VLSI circuit layouts.  With Magic, you use a color graphics
display and a mouse or graphics tablet
to design basic cells and to combine them
hierarchically into large structures.  Magic is different from
other layout editors you may have used.  The most important
difference is that Magic is more than just a color painting
tool:  it understands quite a bit about the nature of circuits
and uses this information to provide you with
additional operations.
For example, Magic has built-in knowledge of layout rules;  as
you are editing, it continuously checks for rule violations.
Magic also knows about connectivity and transistors, and
contains a built-in hierarchical
circuit extractor.  Magic also has a {\itshape plow}
operation that you can use to stretch or compact
cells.  Lastly, Magic has routing tools that you can
use to make the global interconnections in your circuits.

Magic is based on the Mead-Conway style of design.  This means
that it uses simplified design rules and circuit structures.
The simplifications make it easier for you to design circuits
and permit Magic to provide powerful assistance that would
not be possible otherwise.  However, they
result in slightly less dense circuits than you could get with
more complex rules and structures.  For example, Magic permits
only {\itshape Manhattan} designs (those whose edges are
vertical or horizontal).  Circuit designers tell us that our
conservative design rules cost 5-10\% in density.  We
think that the density sacrifice is compensated for
by reduced design time.

\begin{table}[ht]
   \begin{center}
      \begin{tabular}{|l|} \hline
	Magic Tutorial \#1: Getting Started \\
	Magic Tutorial \#2: Basic Painting and Selection \\
	Magic Tutorial \#3: Advanced Painting (Wiring and Plowing) \\
	Magic Tutorial \#4: Cell Hierarchies \\
	Magic Tutorial \#5: Multiple Windows \\
	Magic Tutorial \#6: Design-Rule Checking \\
	Magic Tutorial \#7: Netlists and Routing \\
	Magic Tutorial \#8: Circuit Extraction \\
	Magic Tutorial \#9: Format Conversion for CIF and Calma \\
	Magic Tutorial \#10:  The Interactive Route \\
	Magic Tutorial \#11:  Using RSIM with Magic \\ \hline
	Magic Maintainer's Manual \#1: Hints for System Maintainers \\
	Magic Maintainer's Manual \#2: The Technology File \\
	Magic Maintainer's Manual \#3: Display Styles, Color Maps, and Glyphs \\
	Magic Maintainer's Manual \#4: Using Magic Under X Windows \\ \hline
	Magic Technology Manual \#1: NMOS \\
	Magic Technology Manual \#2: SCMOS \\ \hline
      \end{tabular}
   \end{center}
   \caption{The Magic tutorials, maintenance manuals, and technology manuals.}
   \label{tutorials}
\end{table}

\section{How to Get Help and Report Problems}

There are several ways you can get help about Magic.
If you are trying to learn about the system, you should start
off with the Magic tutorials, of which this is the first.
Each tutorial introduces a particular set of facilities in Magic.
There is also a set of manuals intended for system maintainers.
These describe things like how to create new technologies.
Finally, there is a set of technology manuals.  Each one of
the technology manuals describes the features peculiar to
a particular technology, such as layer names and design rules.
Table~\ref{tutorials} lists all of the Magic manuals.
The tutorials are designed to be read while you are running Magic,
so that you can try out the new commands as they are explained.
You needn't read all the tutorials at once;  each tutorial
lists the other tutorials that you should read first.

The tutorials are not necessarily complete.  Each one
is designed to introduce a set of facilities, but it doesn't
necessarily cover every possibility.  The ultimate authority
on how Magic works is the reference manual, which is a standard
Unix {\itshape man} page.  The {\itshape man} page gives concise
and complete descriptions of all the Magic commands.
Once you have a general idea how a command works, the {\itshape man}
page is probably easier to consult than the tutorial.  However,
the {\itshape man} page may not make much sense until after you've
read the tutorial.

A third way of getting help is available on-line through Magic
itself.  The {\bfseries :help} command will print
out one line for each Magic command, giving the command's syntax
and an extremely brief description of the command.
This facility is useful if you've forgotten the name or exact
syntax of a command.  After each
screenful of help information, {\bfseries :help} stops and prints ``--More--''.
If you type a space, the next screenful of data will be output, and
if you type {\bfseries q} the rest of the output will be skipped.
If you're interested in information about a particular subject,
you can type

\starti
   \ii {\bfseries :help} {\itshape subject}
\endi

This command will print out each command description that
contains the {\itshape subject} string.

If you have a question or problem that can't be answered
with any of the above approaches, you may contact the Magic authors
by sending mail to {\ttfamily magic@ucbarpa.Berkeley.EDU}.
This will log your message in a file (so we can't forget about it) and
forward the message to the Magic maintainers.
Magic maintenance is a mostly volunteer effort, so
when you report a bug or ask a question, {\itshape please} be specific.
Obviously, the more specific you are, the more likely we can answer your
question or reproduce the bug you found.
We'll tend to answer the specific bug reports first, since they involve less
time on our part.  Try to describe
the exact sequence of events that led to the problem, what you
expected to happen, and what actually happened.  If possible,
find a small example that reproduces the problem and
send us the relevant (small!) files so we can make it happen here.
Or best of all, send us a bug fix along with a small example of the problem.

\section{Graphics Configuration}

Magic can be run with different graphics hardware.  The most common
configuration is to run Magic under X11 on a workstation.  Another way
to run Magic is under SunView on a Sun workstation, or under OpenGL
(in an X11 environment) on an SGI workstation or Linux box with
accelerated 3D video hardware and drivers.  Legacy code exists
supporting AED graphics terminals and X10 (the forerunner of X11).
The rest of this section concerns X11.

Before starting up magic, make sure that your {\ttfamily DISPLAY} variable is
set correctly. If you are running magic and your X server on the same
machine, set it to {\ttfamily unix:0}:

\starti
  \ii {\bfseries setenv} {\ttfamily DISPLAY unix:0}
\endi

The Magic window is an ordinary X window, and can be moved and resized using
the window manager.

For now, you can skip to the next major section:  "Running Magic".

\section{Advanced X Use}

The X11 driver can read in window sizing and font preferences from
your {\itshape .Xdefaults} file.  The following specifications are recognized:

\starti
   \> {\bfseries magic.window:}    \ii  1000x600+10+10 \\
   \> {\bfseries magic.newwindow:} \ii  300x300+400+100 \\
   \> {\bfseries magic.small:}     \ii  helvetica8 \\
   \> {\bfseries magic.medium:}    \ii  helvetica12 \\
   \> {\bfseries magic.large:}     \ii  helvetica18 \\
   \> {\bfseries magic.xlarge:}    \ii  helvetica24
\endi

{\bfseries magic.window} is the size and position of the initial window,
while {\bfseries magic.newwindow} is the size and position of subsequent
windows.  If these are left blank, you will be prompted to give
the window's position and size. {\bfseries small}, {\bfseries medium},
{\bfseries large},  and {\bfseries xlarge} are various fonts magic uses
for labels.
Some X11 servers read the {\ttfamily .Xdefaults} file only when you initially
log in; you may have to run {\ttfamily xrdb -load \~{}/.Xdefaults}
for the changes to take
effect.

Under X11, Magic can run on a display of any depth for which there are
colormap and dstyle files.  Monochrome, 4 bit, 6 bit, 7 bit, and 24 bit
files for MOS are distributed in this release.  You can explicitly specify
how many planes Magic is to use by adding a suffix numeral between
1 and 7 to ``XWIND'' when used with Magic's ``-d'' option.
For example, ``magic -d XWIND1'' runs magic on a monochrome
display and ``magic -d XWIND7'' runs magic on a 7 plane display.
If this number is not specified, magic checks the depth of the display
and picks the largest number in the set \{1, 4, 6, 7, 16, 24\} that the display
will support.
Another way to force the display type is to set an environment variable
called {\ttfamily MAGIC\_COLOR} to one of the strings ``8bit'', ``16bit'',
or ``24bit''.

\medskip
\noindent {\bfseries \itshape Linux note:} \\
Magic's ``native'' display (except when using the OpenGL interface)
is the 8-bit PseudoColor visual type.  24-bit TrueColor visuals prevent
Magic from allocating colors for bit-plane logical operations, so the
24-bit interface is visually somewhat sub-par, requiring stipple
patterns on all metal layers, for instance.  Under Linux, a few
(commercial) X drivers will support 8-bit overlays on top of 24-bit
TrueColor when using 32-bit color.  This is the ideal way to use
magic, because the colormap for the rest of the display is preserved
when the cursor is inside the Magic window.  Otherwise, the X session
may have to be started using ``{\ttfamily startx --bpp 8}'' to force
it to use the 8-bit PseudoColor visual.

\medskip
\noindent {\bfseries \itshape X11 remote usage note:} \\
When running Magic remotely on an X terminal, the colormap allocation
may differ for the local machine compared to the remote machine.  In
some cases, this can cause the background of magic to appear black,
usually with a black-on-black cursor.  This is known to be true of
X11 drivers for Windows (such as PC-XWare), due to the way the Windows
8-bit PseudoColor colormap is set up.  This behavior can be corrected
by setting two environment variables on the remote machine as follows:

\starti
   \ii {\bfseries setenv} {\ttfamily X\_COLORMAP\_BASE 128} \\
   \ii {\bfseries setenv} {\ttfamily X\_COLORMAP\_DEFAULT 0} \\
\endi

This causes Magic to avoid trying to allocate the first color
in the colormap, which under Windows is fixed as black.

\section{Running Magic}

From this point on, you should be sitting at a Magic workstation
so you can experiment with the program as you read the manuals.
Starting up Magic is usually pretty simple.  Just log in and, if needed,
start up your favorite window system.  Then type the shell command

\starti
   \ii {\bfseries magic tut1}
\endi

{\bfseries Tut1} is the name of a library cell that you will play
with in this tutorial.
At this point, several colored rectangles should appear
on the color display along with a white box and a cursor.
A message will be printed on the text display to tell you that
{\bfseries tut1} isn't writable (it's in a read-only library),
and a ``$>$'' prompt should appear.
If this has happened, then you can skip the rest of this
section (except for the note below) and go directly to Section 5.

Note: in the tutorials, when you see things printed in boldface,
for example, {\bfseries magic tut1} from above, they refer to things
you type exactly, such as command names and file names.  These
are usually case sensitive ({\bfseries A} is different from {\bfseries a}).
When you see things printed in italics, they refer to classes of
things you might type.  Arguments in square brackets are optional.
For example, a more complete description
of the shell command for Magic is

\starti
   \ii {\bfseries magic} [{\itshape file}]
\endi

You could type any file name for {\itshape file}, and
Magic would start editing that file.  It turns out that {\bfseries tut1}
is just a file in Magic's cell library.  If you didn't type a
file name, Magic would load a new blank cell.

If things didn't happen as they should have when you tried to
run Magic, any of several things could be wrong.  If a message
of the form ``magic: Command not found'' appears on your screen
it is because the shell couldn't find the Magic program.  The
most stable version of Magic is the directory {\ttfamily \~{}cad/bin},
and the newest public version is in {\ttfamily \~{}cad/new}.  You should
make sure that both these directories are in your shell path.
Normally, {\ttfamily \~{}cad/new} should appear before {\ttfamily \~{}cad/bin}.
If this sounds like gibberish, find a Unix hacker and have him or her
explain to you about paths.  If worst comes to worst, you can invoke
Magic by typing its full name:

\starti
   \ii {\bfseries \~{}cad/bin/magic tut1}
\endi

Another possible problem is that
Magic might not know what kind of display you are using.
To solve this, use magic's {\bfseries -d} flag:
\starti
  \ii {\bfseries magic -d} {\itshape display} {\bfseries tut1}
\endi
{\itshape Display} is usually the model number of the workstation you are using or
the
name of your window system.  Look in the manual page for a list of valid
names, or just guess something.  Magic will print out the list of valid names
if you guess wrong.

If you are using a graphics terminal (not a workstation),
it is possible that Magic doesn't know which serial line to use.  To learn
how to fix
this, read about the {\bfseries -g} switch in the magic(1) manual page.  Also read
the displays(5) manual page.

\section{The Box and the Cursor}

Two things, called the {\itshape box} and the {\itshape cursor}, are used
to select things on the color display.  As you move the
mouse, the cursor moves on the screen.  The cursor starts out
with a crosshair shape, but you'll see later that its shape
changes as you work to provide feedback about what you're
doing.  The left and right
mouse buttons are used to position the box.  If you press the
left mouse button and then release it, the box will move so
that its lower left corner is at the cursor position.  If
you press and release the right mouse button, the upper right
corner of the box will move to the cursor position, but the
lower left corner will not change.  These two buttons are
enough to position the box anywhere on the screen.  Try using
the buttons to place the box around each of the colored rectangles
on the screen.

Sometimes it is convenient to move the box by a corner other
than the lower left.  To do this, press the left mouse button
and {\itshape hold it down}.  The cursor shape changes to show you
that you are moving the box by its lower left corner:

\begin{center}
   \begin{tabular}{|c|} \hline
	\hspace*{0.1in} \\ \hline
   \end{tabular}
\end{center}

While
holding the button down, move the cursor near the lower right
corner of the box, and now click the right mouse button (i.e.
press and release it, while still holding down the left
button).  The cursor's shape will change to indicate that
you are now moving the box by its lower right corner.  Move
the cursor to a different place on the screen and release
the left button.  The box should move so that its lower right
corner is at the cursor position.  Try using this feature to
move the box so that it is almost entirely off-screen to the
left.  Try moving the box by each of its corners.

You can also reshape the box by corners other than the upper
right.  To do this, press the right mouse button and hold
it down.  The cursor shape shows you that you are reshaping
the box by its upper right corner:

\begin{center}
   \begin{tabular}{c|} \hline
	\hspace*{0.1in} \\
   \end{tabular}
\end{center}

Now move the cursor
near some other corner of the box and click the left button,
all the while holding the right button down.  The cursor
shape will change to show you that now you are reshaping the
box by a different corner.  When you release the right button,
the box will reshape so that the selected corner is at
the cursor position but the diagonally opposite corner is unchanged.
Try reshaping the box by each of its corners.

\section{Invoking Commands}

Commands can be invoked in Magic in three ways:  by pressing
buttons on the mouse;  by typing single keystrokes on the
text keyboard (these are called
{\itshape macros}); or by typing longer commands on the text
keyboard (these are called {\itshape long commands}).  Many of the
commands use the box and cursor to help guide the command.

To see how commands can be invoked from the buttons, first
position the box over a small blank area in the middle of the
screen.  Then move the cursor over the red rectangle and
press the middle mouse button.  At this point, the area of the box should
get painted red.  Now move the cursor over empty space and
press the middle button again.  The red paint should go away.
Note how this command uses both the cursor and box locations
to control what happens.

As an example of a macro, type the {\bfseries g} key on
the text keyboard.  A grid will appear on the color display, along
with a small black box marking the origin of the cell.
If you type {\bfseries g} again, the grid will go away.  You
may have noticed earlier that the box corners didn't move to
the exact cursor position:  you can see now that the box is
forced to fall on grid points.

Long commands are invoked by typing a colon (``:'') or
semi-colon (``;'').  After you
type the colon or semi-colon, the ``$>$'' prompt on the text
screen will be replaced by a ``:'' prompt.  This indicates
that Magic is waiting for a long command.  At this point
you should type a line of text, followed by a return.
When the long command has been processed, the ``$>$'' prompt
reappears on the text display.  Try typing semi-colon followed by
return to see how this works.  Occasionally a ``]'' (right bracket)
prompt will appear.  This means that the design-rule checker is reverifying
part of your design.  For now you can just ignore this and treat
``]'' like ``$>$''.

Each long command consists of the name of the command followed
by arguments, if any are needed by that command.  The command
name can be abbreviated, just as long as you type enough
characters to distinguish it from all other long commands.
For example, {\bfseries :h} and {\bfseries :he} may be used as abbreviations for
{\bfseries :help}.  On the other hand, {\bfseries :u} may not be used as an
abbreviation for {\bfseries :undo} because there is another command,
{\bfseries :upsidedown}, that has the same abbreviation.  Try typing
{\bfseries :u}.

As an example of a long command, put the box over empty space on
the color display, then invoke the long command

\starti
   \ii {\bfseries :paint red}
\endi

The box should fill with the red color, just as if you had
used the middle mouse button to paint it.  Everything you can
do in Magic can be invoked with a long command.  It turns out that
the macros are just conveniences that are expanded into long
commands and executed.  For example, the long command equivalent
to the {\bfseries g} macro is

\starti
   \ii {\bfseries :grid}
\endi

Magic permits you to define new macros if you wish.  Once you've
become familiar with Magic you'll almost certainly want to add
your own macros so that you can invoke quickly the commands you
use most frequently.  See the
{\itshape magic(1)} man page under the command {\bfseries :macro}.

One more long command is of immediate use to you.  It is

\starti
   \ii {\bfseries :quit}
\endi

Invoke this command.  Note that before exiting, Magic will
give you one last chance to save the information that you've
modified.  Type {\bfseries y} to exit without saving anything.

\end{document}