with slashes in the name (picks up the text after the last slash).
Also allowed the "gds library" command option to modify the
behavior of "gds read" (previously only affected "gds write") to
indicate that the GDS file is a library and that there are no top-
level contents, only subcell definitions. Also: Corrected a typo
from yesterday's commit that prevents magic from compiling (oops).
polygon cell has been created with the "gds polygon subcell"
option and the parent cell is read-only (vendor GDS), then the
polygon cell does not actually exist in the original GDS and
should not be output during a "gds write".
fringe capacitance halo where the default halo distance was set to
zero instead of one and caused divide-by-zero issues; (2) Found
extraction issues where labels picked up from cells flattened
during GDS reading cause the flattened/emptied cells to show up
in the extraction with extra pins that can mess up LVS. Solved
this by removing labels from flattened/emptied cells.
reading GDS files, caused by an unneeded change to pass both
the "original" filename and the actual filename when handling
compressed files---The original filename is unneeded.
(2) Implemented several new methods for parasitic extraction. The
first is an option offset value to apply to sidewall calculations.
This handles issues where actual wire separation is different
from drawn wire separation, which can be significant for the
1/d calculation of sidewall coupling. The second method is to
use the recently-added fringe halo to compute the coupling of the
fringe capacitance to nearby wires. Prior to this change, all
fringe capacitance was applied to surfaces directly under a wire
edge as if the fringe capacitance did not extend outward from the
edge. Now the capacitance is properly pro-rated for the position
of any overlapped shape inside the fringing field. Finally, the
third method added is a new search algorithm for finding the
nearest shapes along the length of a boundary. This is used for
sidewall coupling and fringe shielding, where the nearest shape
dominates the coupling, and any shapes behind are shielded and
may (to first order) be ignored. Previously, the entire halo
was searched without regard to shapes shielding other shapes
behind, and a recent correction added an ad-hoc search for
blocking shapes that was inefficient and not always correct.
The new method is both efficient and accurate.
Compression levels of the output can be controlled with the "gds
compress [<value>]" command, where <value> 0 (default) is uncompressed
output, 6 is "normal" gzip compression, and 9 is maximum compression.
pointing GDS_FILE to a compressed filename when using "gds readonly
true" on a compressed file. The start and end pointers still point
to data bounds in the uncompressed file.
of systems calls to "gzip" and "gunzip". A compressed GDS file can
be made simply by doing "gds write <name>.gds.gz", and can be read
simply by doing "gds read <name>.gds.gz". Names of compressed files
can be put in the GDS_FILE property of a cell.
timestamps that are fixed, since the timestamp update routine is
called from too many places, too many times. Instead created a
new cell definition flag indicating a fixed timestamp, which can
be set by "cellname timestamp" for an individual cell, or with
"gds datestamp" for cells read from a GDS file.
the timestamp is updated after reading in CIF or GDS, and managed to
get the timestamp dirty flag to remain clear after reading when
"gds datestamp" is used. This includes a modification of the timestamp
update routine that only updates timestamps on a single file if only a
single file is being written.
"writeall force <cell>" is used but <cell> doesn't exist, and (2)
to add options "writeall modified" and "writeall noupdate" (which
may or may not be useful).
yesterday's commit to allow the syntax "gds maskhints <types>", in
which mask hints can be restricted to a specific list of layers
rather than all layers which define mask hints in the cifoutput
rule.
behavior, in which all cells read from GDS are given a zero
timestamp, and the timestamp is set when the file is written to
disk, the default behavior now is to set the layout cell's timestamp
from the timestamp provided in the GDS (the creation date timestamp,
specifically). The same command "gds datestamp" implemented in the
previous commit for GDS writes now also applies to GDS reads: If
set to "no", then the timestamp value from the GDS file is
transferred to the layout view (default behavior); if set to "yes",
then the timestamp is set to zero (legacy behavior). If set to
a value, then the value is used as the timestamp.
"gds datestamp <value>" as an option to force a specific datestamp
on the GDS output. This is a third option beyond the previous two
which were either to use the current time or to write zero. The
new option allows an entire library to get a common timestamp, for
example, related to a PDK version number. The "gds nodatestamp"
option has been retained for backwards compatibility.
in a cell to account for the difference between what's in an input
GDS file and what magic would write out itself from the processed
data. This potentially allows library cells to be read in that
will generate the equivalent mask data as output without resorting
to using GDS file references as properties. The method is activated
with the new command option "gds maskhints on" and the default is
off.
If cells are instanced before being defined, causing the GDS parser
to rewind the cell from the top, then the "already defined" error
messages will be suppressed, since it is to be expected that cells
will be seen twice (and ignored the 2nd time). When rewinding, an
output message is issued so that it is clear that the file contains
instances that are used before they are defined, and recommends the
"gds ordering on" setting. Also: Fixed the "gds ordering" command
code so that the command with no third argument returns the state
of the "gds ordering" setting instead of generating a parser error.
post error messages when a GDS library addendum is read. It now
assumes that if a cell is called but not defined in the GDS, and
that cell happens to be in memory already, then this is intentional.
this limited ports to 16384, which seemed reasonable at the time.
However, the sky130_sram_macro layouts connect power and ground in a
way that when coupled with "extract unique" can generate tens of
thousands of ports and overrun the bit field, showing that automation
can do the unexpected. The solution was to split out the port number
from the label record as its own 32-bit value.
it is easy to subvert the process by updating GDS without updating
the pointers, it is trivial to end up with bad GDS output. The
sanity checks confirm that the position pointed to is a complete
structure (check begin and end records), and that it has the same
name as the cell (this is not a requirement, as there are reasons
one might want to point to data from a structure of a different
name, but a warning will be printed).
cell is referenced by a GDS "addendum" file but is not in either
the tree of the root def or any other dumped GDS file, then check
the database for those files and output them if they exist. This
allows one way to get around missing cells in the GDS output if a
cell from a GDS addendum is used but no cells from the library
that the file is an addendum of are used.
introduced: The use of substitutions for PDKPATH and home directory
in path names for GDS files referenced in abstract views, and the
"gds addendum" option. Both were interfering with magic's handling
of writing GDS files from abstract layout views.
from 98 (arbitrarily selected) to 61 (apparently commonly used by
other tools). This should help increase compatibility with GDS
files output from other tools.
the last commit, unfortunately. Thanks to Matt Guthaus for alerting me
to this. Also updated parts of the extresist code that remove the
dependence on ResConDCS; this is a minor update and should not affect
the operation of extresist. It is preparatory to doing more work to
support additional device types like capacitors, bipolars, and diodes.
in which if a cell is read from GDS that has the same name as a cell
in memory, then the cell in memory is renamed to keep all cell names
unique in the database.
This can be done now by reading a LEF file, followed by reading
a GDS file with the "noduplicates" option set. In addition,
annotation of either the LEF view or a read-only view follows the
same protocol as cell paths in the .mag file, which is to replace
leading path components matching Tcl variables for PDKPATH or
PDKROOT, and replace the home directory path with a tilde.
worded warning if an abstract cell view is written to GDS.
Corrected the "cellname ... writeable" command to allow an
overrride of the read-only status of a cell. That change had
been made before but apparently got reverted by the recent
rollback.
flattened per "gds flatten" or "gds flatglob", and the "gds readonly"
option is not set, then the instances of the flattened cells are
removed from the layout. They are retained for the "readonly" option
because when writing GDS of such a cell, the full hierarchy needs to
be walked.
from slashes in hierarchical names. Magic does not allow slashes
in names when using "identify", so the simplest solution is just
to prohibit them in names being read from GDS files, and replace
them with underscores to make them magic-compatible. Changing
GDS names always has repercussions on things like back-annotating
delays, so it should probably be revisited in the future.
it as a single value "flags" (unsigned char) with meaningful flag
names. Added new option "-fail" to the load command to allow
magic to fail on loading a cell that does not have a corresponding
file rather than the default action of creating a new cell. Added
a flag for the "-quiet" option so that behavior on "-fail" can be
done quietly.
cell def that is marked for a "full dump" from a referenced GDS
file. This change was supposed to have been done a few commits
ago but did not work as advertised.
magic database derived layout of a cell that declares GDS_FILE
but for which the GDS file referenced cannot be found or read.
This will produce an incomplete GDS file instead of an apparently
good and complete GDS file that actually contains bad data. Also:
Added new command "random" that allows a random seed to be set,
for use with the GDS output when writing a full dump of a GDS
file. Otherwise, the output prefixes are always the same, which
defeats the purpose of adding the random prefix.
to stop the search whenever a cell is not found. Used this to implement
a new option for GDS writes, "gds undefined allow|disallow" (default
"disallow") controls whether or not GDS with undefined references will
be allowed to be written. Similarly affects CIF and LEF writes, extraction,
and DRC (when running "drc check" from the top).
"gds write" command, since "Writing cell" is easily confused with
writing a .mag database file. "Generating output" seems clearer
to me. Maybe it's just me.
Tim Edwards
Anton Blanchard