1MAGIC(5) File Formats Manual MAGIC(5)
2
6 magic - format of .mag files read/written by Magic
7
10 Magic uses its own internal ASCII format for storing cells in disk
11 files. Each cell name is stored in its own file, named name.mag.
12 The first line in a .mag file is the string
14 magic
16 to identify this as a Magic file.
18 The next line is optional and is used to identify the technology in
20 which a cell was designed. If present, it should be of the form
21 tech techname
23 If absent, the technology defaults to a system-wide standard, currently
25 nmos.
26 The next line is also optional and gives a timestamp for the cell. The
28 line is of the format
29 timestamp stamp
31 where stamp is a number of seconds since 00:00 GMT January 1, 1970
33 (i.e, the Unix time returned by the library function time()). It
34 should be the last time this cell or any of its children changed. The
35 timestamp is used to detect when a child is edited outside the context
36 of its parent (the parent stores the last timestamp it saw for each of
37 its children; see below). When this occurs, the design-rule checker
38 must recheck the entire area of the child for subcell interaction
39 errors. If this field is omitted in a cell, Magic supplies a default
40 value that forces the rechecks.
41 Next come lines describing the contents of the cell. There are three
43 kinds of groups of lines, describing mask rectangles, subcell uses, and
44 labels. Each group must appear contiguously in the file, but the order
45 between groups is arbitrary.
46 Each group of mask rectangles is headed with a line of the format
48 << layer >>
50 where layer is a layername known in the current technology (see the
52 tech line above). Each line after this header has the format
53 rect xbot ybot xtop ytop
55 where (xbot, ybot) is the lower-left corner of the rectangle in Magic
57 (lambda) coordinates, and (xtop, ytop) is the upper-right corner.
58 Degenerate rectangles are not allowed; xbot must be strictly less than
59 xtop, and ybot strictly less than ytop. The smallest legal value of
60 xbot or ybot is −67108858, and the largest legal value for xtop or ytop
61 is 67108858. Values that approach these limits (within a factor of 100
62 or 1000) may cause numerical overflows in Magic even though they are
63 not strictly illegal. We recommend using coordinates around zero as
64 much as possible.
65 Rectangles should be non-overlapping, although this is not essential.
67 They should also already have been merged into maximal horizontal
68 strips (the neighbor to the right or left of a rectangle should not be
69 of the same type), but this is also not essential.
70 The second kind of line group describes a single cell use. Each cell
72 use group is of the following form:
73 use filename use-id
75 array xlo xhi xsep ylo yhi ysep
76 timestamp stamp
77 transform a b c d e f
78 box xbot ybot xtop ytop
79 A group specifies a single instance of the cell named filename, with
81 instance-identifier use-id. The instance-identifier use-id must be
82 unique among all cells used by this .mag file. If use-id is not speci‐
83 fied, a unique one is generated automatically.
84 The array line need only be present if the cell is an array. If so,
86 the X indices run from xlo to xhi inclusive, with elements being sepa‐
87 rated from each other in the X dimension by xsep lambda. The Y indices
88 run from ylo to yhi inclusive, with elements being separated from each
89 other in the Y dimension by ysep lambda. If xlo and xhi are equal,
90 xsep is ignored; similarly if ylo and yhi are equal, ysep is ignored.
91 The timestamp line is optional; if present, it gives the last time this
93 cell was aware that the child filename changed. If there is no time‐
94 stamp line, a timestamp of 0 is assumed. When the subcell is read in,
95 this value is compared to the actual value at the beginning of the
96 child cell. If there is a difference, the ``timestamp mismatch'' mes‐
97 sage is printed, and Magic rechecks design-rules around the child.
98 The transform line gives the geometric transform from coordinates of
100 the child filename into coordinates of the cell being read. The six
101 integers a, b, c, d, e, and f are part of the following transformation
102 matrix, which is used to postmultiply all coordinates in the child
103 filename whenever their coordinates in the parent are required:
104 a d 0
106 b e 0
107 c f 1
108 Finally, box gives an estimate of the bounding box of cell filename
110 (covering all the elements of the array if an array line was present),
111 in coordinates of the cell being read.
112 The third kind of line group in a .mag file is a list of labels. It
114 begins with the line
115 << labels >>
117 and is followed by zero or more lines of the following form:
119 rlabel layer xbot ybot xtop ytop position text
121 Here layer is the name of one of the layers specified in the technology
123 file for this cell. The label is attached to material of this type.
124 Layer may be space, in which case the label is not considered to be
125 attached to any layer.
126 Labels are rectangular. The lower-left corner of the label (the part
128 attached to any geometry if layer is non-space) is at (xbot, ybot), and
129 the upper-right corner at (xtop, ytop). The width of the rectangle or
130 its height may be zero. In fact, most labels in Magic have a lower-
131 left equal to their upper right.
132 The text of the label, text, may be any sequence of characters not
134 including a newline. This text is located at one of nine possible ori‐
135 entations relative to the center of the label's rectangle. Position is
136 an integer between 0 and 8, each of which corresponds to a different
137 orientation:
138 0 center
140 1 north
141 2 northeast
142 3 east
143 4 southeast
144 5 south
145 6 southwest
146 7 west
147 8 northwest
148 A .mag file is terminated by the line
151 << end >>
153 Everything following this line is ignored.
155 Any line beginning with a pound sigh (``#'') is considered to be a com‐
157 ment and ignored. Beware, however, that these comments are discarded
158 by Magic when it reads a cell, so if that cell is written again by
159 Magic, the comments will be lost.
160
163 Magic's incremental design rule checker expects that every cell is
164 either completely checked, or contains information to tell the checker
165 which areas of the cell have yet to be examined for design-rule viola‐
166 tions. To make sure that the design-rule checker verifies all the
167 material that has been generated for a cell, programs that generate
168 .mag files should place the following rectangle in each file:
169 << checkpaint >>
171 rect xbot ybot xtop ytop
172 This rectangle may appear anywhere a list of rectangles is allowed;
174 immediately following the timestamp line at the beginning of a .mag
175 file is a good place. The coordinates xbot etc. should be large enough
176 to completely cover anything in the cell, and must surround all this
177 material by at least one lambda. Be careful, however, not to make this
178 area too ridiculously large. For example, if you use the maximum and
179 minimum legal tile coordinates, it will take the design-rule checker an
180 extremely long time to recheck the area.
181
184 magic(1)
1854th Berkeley Distribution MAGIC(5)