previous behavior that had inadvertently been changed. In recent
versions, "load <absolute_path> -dereference" would incorrectly
apply the dereferencing to <absolute_path> rather than just its
subcells. Cleaned up the code around DBCellRead() in the process,
so everything is more straightforward (although probably more
could be done in that regard).
to "safer" strncpy() calls to prevent string buffer overflow.
Also: Reimplemented the loop in the GDS write routine that counts
ports and then outputs them in order. It was possible to hang
magic for a long time by giving a port a very, very large index
number. The new implementation uses qsort() to sort the ports
by index, which is obviously much more efficient for the worst
case (and efficient enough for all normal cases).
dereferencing, and making the behavior of "load" on the command
line (i.e., loading a cell from a file) the same as the
behavior of loading a cell as a result of expanding an unloaded
instance. In both cases, if "load -dereference" is used, and
a cell does not exist in any search path but does exist in the
original location, without dereferencing, then the cell will be
loaded from the original location. Also: Corrected an error
that has existed since adding the capability to read compressed
files, which causes magic to crash when attempting to run the
"crash recover" command (because that routine was mixing
compressed and regular file stream calls).
ground node name (which is static) gets put on the node list and
is improperly deallocated. Corrected by simply allocating the
string for the default substrate node instead of using the static
string.
"cif *hier write disable" and "cif *array write disable" commands
for a specific cell def and its descendents. The revision ensures
that all descendents apply the override. The "cif write" command
uses a stack instead of recursion, which makes it difficult to
apply the same method. Currently the method only works for the
"gds write" command, and implementing the feature for "cif write"
is deemed not worth the effort.
This is diagnostic only and does not change the read-in
behavior.
(2) ext2spice: Corrected an error that had been introduced
into version 8.3.171 that accidentally marks all devices
as visited which causes all source/drain areas and
perimeters to be output as zero.
(3) extract: Sweeping changes to handling of fringe
capacitance. Removed the (recently added) "fringeshieldhalo"
parameter from the tech file. Reworked the fringe
capacitance models based on results from the "capiche"
project (github/RTimothyEdwards/capiche). Fringe shielding
is now done by clipping fringe at the boundary of a
shielding shape, rather than trying to calculate the
amount of shielding (as the "capiche" project proved this
to be equivalent). Values for partial fringing are modeled
by atan(x), which like the sidewall (1/x) curve, extends to
infinity and values are limited by the halo but do not
otherwise depend on the halo. Because of this, the halo can
be made variable and controlled by the user for deciding on
the tradeoff between accuracy and run time. A new command
option "extract halo" was added to allow this control over
the halo distance.
three types: "none", "temporary", and "keep" (instead of "true"
or "false"). "none" now reverts back to the original behavior,
because it was found that saving polygons in subcells prevents
them from participating in boolean operations. The "keep"
option is the original option (polygons kept in subcells), and
"temporary" is the one recently introduced (which puts polygons
in subcells and then flattens them). This restores the original
method while retaining the recently implemented method. However,
a proper solution needs to be found that deals with the problem
of boolean operators.
tech file to correct the underlying problem with the SkyWater
sky130 process in which a different layer/purpose pair is used
for TEXTTYPE and DATATYPE for the same layer. Previously, all
output from magic writes the same pair for both when writing a
port label. The new method preserves existing syntax, although
there are some differences based on what order the "port"
statement appears relative to other types for the same layer.
that the feature for implementing callbacks on a selection list
was already implemented via the add_dependency procedure.
Modified the GDS read to remove cell instances that are placed
directly on top of one another in the same cell. Modified the
GDS read to make a better selection of a default font size for
text that specifies a font but not a size, using the minimum
width for the layer the text is placed on. Modified the GDS
read to remove text with empty-string placeholders (created when
a pin layer is read but no text exists to go along with it, due
to GDS not having a specific way to make pins, such that pins
have to be split between one record for geometry and another
for text).
should have been done a long time ago! Allows an instance to be
flattened in place inside a cell def, which otherwise requires
a complicated set of commands to do. Also: Modified the polygon
handling routine from the previous commit so that it correctly
removes the polygon cell defs after flattening them into the
parent cell.
can be much, much faster than reading in polygons directly into a
cell from GDS. Modified the handling of polygons so that they are
*always* read into subcells. If the "polygon subcell flatten true"
option is not enabled, then the subcells are flattened at the end
of reading the cell, and the polygon cells are deleted. This method
avoids most of the cases in which "polygon subcell flatten true"
has ever needed to be set.
due to a missing function prototype. Modified the GDS output
flow to always output instance IDs as a property, not just in the
non-default case. The property has been used for many years and
appears to be accepted by all tools reading GDS, so there is no
downside to always generating this output. This has the upside
that default instance names don't get scrambled by going from
magic to GDS and back to magic.
for the squares-grid operator and for GDS compression. But I
reverted the "calma contact" option to be false by default, because
the method does not exactly match the output when not using cell
instance arrays, and so may produce unexpected results. Will
need a different implementation that uses the same code to generate
the same (effective) layout.
default behavior of magic to make use of the "gds contacts true"
option to output contacts as arrays of subcells instead of
individual boundary entries, as the former is much more efficient
than the latter. Set the option to be true by default, and set
the "gds flatglob" option to have one entry "$$*$$" corresponding
to the contact subcells created by the "gds contacts" option, so
that GDS reads and writes as it did previously (but using a
different method). Expanded the method to include "squares-grid"
and "slots" operators (the latter should produce much more
efficient fill pattern arrays). Implemented for both compressed
and uncompressed GDS. Tested in all variations.
supported). Fixed the long-standing issue in which DRC does not
get stopped by the "drc off" command (the behavior for interrupting
the DRC was dependent on the DRC being turned on, and the "drc off"
command was turning it off before breaking, causing the interrupt
to be ignored).
attempt is made to write an abstract view to GDS. This behavior can
be overridded with the new command option "gds abstract [enable|disable]".
Also: Corrected extraction to allow split tiles to be set as the
reference tile for a node. Previously this was allowed only if the
tile was the first to be searched, but that can cause different tiles to
be marked as the reference depending on where the search starts,
resulting in different names for the same node in .ext files, which is
bad. Also: Modified the LEF annotation to avoid bad entries in the LEF
that would create layers in the layout where none exist.
Alessandro De Laurenzis. That pull request cleaned up the vast
majority of compiler warnings. However, that cleanup exposed a
few additional warnings pointing to errors in the code that needed
fixing. The code now compiles cleanly except for one warning
about redefined CAD_DIR that I have not looked into.
This commit makes the code (mostly) C99-compatible, enabling to compile
it without the -Wno-error=implicit-function-declaration flag. This
way, Magic becomes usable on arm64 architectures, specifically on Apple
computers with M1/M2 SoC.
calculation of the area to check for output and the clip box
does not reduce the size of any layer associated with the
fixed bounding box declared by the FIXED_BBOX property.
record. Failure to use the right 8-byte real format can produce
bizarre results where a label's bounding box ends up in some random
place and messes up an entire top level circuit's bounding box.
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.
Johan Euphrosine
Tim Edwards
Alessandro De Laurenzis