extraction. The plane mask array that denotes for each type which
planes should be searched for connecting types is supposed to be
a rare case that covers situations where planes connect by types
that are not contacts. Instead, many planes were in this array,
causing the worst-case extraction methods to be run constantly.
the undo mechanism in the wrong state when writing a LEF header
with no route track information. Also added code to the DEF write
routine to handle subcell arrays. Thanks to Martin Devera for
both patches.
DRC rules. The substitutions are specified by "%d" for the main
rule distance, "%c" for the corner rule distance (sometimes
interpreted differently; e.g., as width in the widespacing rule),
and "%a" for rule area (e.g., maxarea rule). In addition to
simplifying the process of writing rule violation strings, the
benefits are twofold: (1) The output is in meaningful physical
units, but in the case of SCMOS technology, will scale properly
depending on the selected GDS output style, and in the case of
all technologies, will scale properly with internal grid division;
and (2) when using lambda, but where rules are given in vendor
minimum dimensions, the rules will be based on the lambda rule
approximation (that is, distances will be rounded to the nearest
lambda but reported in microns). Behavior is unchanged from
previous versions for "why" strings not using the defined
substitution sequences.
name-to-number mapping used for the HSPICE format between
subcircuits. Otherwise, subcircuits with the same instance ID
remain in the table and may cause nodes to be output with a name
that collides with other names in the same subcircuit. This only
affects output in HSPICE format.
"echo", because there is at least one OS variant out there where
the two buffer independently and cause the output to have lines
out of order. The script had previously used "printf" because
"echo -n" is not POSIX-compliant and so not necessarily universally
compatible. The script was changed to use "printf" throughout.
the output to have an obstruction area over the entire cell except
for a keep-out area around each pin. Instead of marking every
part of the pin geometry, only the "chunk" (largest immediate
rectangle) surrounding the port label is output as part of port
LEF geometry. This avoids making unnecessarily complicated
abstract views, and makes it easier for other tools to read and
manage the same abstract views.
to prefix all library components read from GDS files pointed to by
an abstract view (other than the cell itself) with a prefix. But
this does not account for the fact that the same library may be read
by other cells. The solution is for every cell in the library, check
if there is a cell in magic with the same name which is also an abstract
view that points to the same GDS library. Those cells do not get
prefixes. At the same time, however, it was discovered that the GDS
cellname character limit is set at 32, and so prefixes must be kept
short. To keep the prefixes unique, the prefix was changed to a 4
character random alphanumeric sequence, and a warning is issued if
any GDS cell exceeds the 32 character limit.
options "text", "port", and "noport" in the techfile. The
incorrect interpretation was preventing backwards compatibility,
such that ports would not be output on GDS layers if the "port"
option was not used.
all the settings normally used for LVS (hierarchy on, cthresh
infinite, subcircuit top auto, etc.). (2) Extract and extract
unique ignore cells marked as abstract views (property LEFview
is set) when checking for unconnected nets with the same name
label.
in the SPICE netlist when using new device "csubcircuit" due to
a mismatch in the expected number of parameters. However, more
work needs to be done to cover capacitor top and bottom plates on
different planes.
added a long time ago, since capacitors use a different method for
calculating width and length than either transistors or resistors,
so subcircuits need a special class designator or else the extraction
may calculate the wrong dimensions for device width by totalling the
perimeter between the device and terminal types, as it would for a
MOSFET.
Tim Edwards
Tim Edwards