depending on the order of extraction devices. Specifically, the
case of a source-drain tied FET was breaking out of a loop when
it should have been breaking out of a double loop.
can provide a delta offset such as "l+0.06", indicating that
the extraction model has a length larger than the drawn device.
Previously the value was assumed to be in microns but did not
scale between the .ext file and the SPICE netlist. Corrected
so that it scales like the other parameter values, being
converted to internal units and tracking the internal grid
scale.
"unexpected asymmetric device" is printed prematurely, as it
is inside a loop checking over all device entries compatible
with a device type. Also: Flagged an issue with the "label"
keyword in the "cifinput" section of a tech file. The "label"
keyword cannot be used in conjunction with boolean operators.
It can only connect labels on a specific GDS type to one magic
type. Unfortunately, because this was not flagged before as
an error or warning, the incorrect usage has crept into a lot
of tech files. This uncovers an underlying issue that labels
must be allowed to automatically reconnect types, which is
undermined by the "no-reconnect-labels" cifinput option. That
issue will be addressed in an upcoming commit.
front of the list during extraction, except that after copying
they're not. Removed the expectation, although that causes the
entire linked list of labels to be parsed and may cause excessive
run-times in pathological situations. Keep an eye out for
unintended consequences.
warning messages about ports being electrically connected when
those ports have names that match under rules of case-insensitivity,
and the .ext file is being read for the purpose of generating a
SPICE netlist, which is case-insensitive. Also: Corrected a crash
condition when using "extract path <name>" when directory <name>
does not exist.
to be declared for each device model, so that different models can
be specified for different parameter ranges. For example, this
will simplify the definition of the high-sheet-rho poly resistors
and the bipolar transistors in sky130 by removing the need for ID
marker layers; it also allows the correct device model to be
extracted when reading data from GDS that does not contain the
extra (and not foundry-approved) ID markers.
list for output, but that the code in ExtRegion.c does not sort a
region's label list to keep ports at the beginning of the list. So
any net with multiple labels may end up with a non-port label as
the name of the node, which eventually becomes the name of the port.
A quick fix keeps these lists sorted.
be output twice for scaled devices (such as diodes in the sky130
process). Above and beyond the typo, though, the implementation
of offsets is not very well thought out and needs to be revised.
For one, the +/- notation can be confused with signs in the
parameter expression; that is also fixed in this commit. But
there is currently no way to express both a scale and an offset
for a device parameter.
'+' and '-' in the same way that '*' is currently used for specifying
a parameter scaling. The combination of a scale and offset for the
same parameter has not (yet) been implemented.
with "extract do local" now being equivalent to "extract path .".
This allows extraction files to be put in a subdirectory and not
clog up the current working directory. Also: Fixed some behavior
around the use of "ext2spice -p <path>" so that it (1) works, and
(2) is compatible with the new "extract path". Since the ext2spice
and ext2sim commands are effectively independent of the primary
extraction, the "-p" option is needed to correspond to the use of
"extract path". Hopefully this is seen as only a minor inconvenience.
from ext2spice due to "equiv" statements in the .ext file. The
algorithm was not properly keeping the port as the preferred
name of the node, resulting in the non-preferred name being
used instead of the port name in the output. This would happen
only if there was a label on a net that had a different name than
the port name. The error became much more prevalent after changing
the extract behavior to make "extract do aliases" default. Also
fixed a somewhat related minor error in which magic would print an
error message about ports being shorted together on the same kind
of net where both a port and a (different) label were attached to
the net. Since the non-port label is not a preferred name, then
there should be no warning message. The warning is only intended
for cases where two (or more) ports are truly shorted together.
perimeter are not initialized, and if a terminal perimeter/area
calculation is missed (which is happening on devices with terminals
in planes other than the plane of the identifying type), then the
perimeter/area of a previously handled device will get output.
(2) Corrected an error with "flatten -inplace" in which the command
fails to deal with instance arrays.
"space" is considered part of the substrate, then the check for
planes to search should exclude "space" from the type mask
first. Otherwise, all planes get searched, not just the substrate.
Also: The same routine can falsely flag a device terminal as
substrate if a split tile is marked as the device's region. This
was also fixed.
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).
labels that are not connected to their declared layers. It's the
latter type that need additional processing in ExtSubtree.
Limiting this processing significantly cuts down on processing
time when there are many labels in a layout, as happens with the
"def read -labels" command option.
partitioning of unshielded areas reaching outward from any given
edge, caused by using a boundary value in the 2nd recursion call
that had been modified for the 1st recursion call and so was no
longer valid.
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).
computing the amount of fringe shielding was wrong. This fixes
one of my example cases, but not the other one, so I still need to
pin down a condition that can result in negative capacitance.
inside a halo area. The previous implementation used a linear
accounting of error to determine the amount of shielding, but
since the shielding is nonlinear, this is a poor approximation
and regularly overestimates the shielding and leads to negative
capacitances. The corrected method makes many more calls to
the atan() function and the performance impact for extraction
will need to be evaluated.
(truly) missing a terminal (such as a MOSCAP made with a gate
extending into but not crossing a diffusion region). Added the
most requested GUI feature, which is a vertical scrollbar on the
parameterized device window (could be improved by maximizing
window height without exceeding display height).
222 from Sean Cross. Corrected a few places where the blanket
conversion "Region"->"ExtRegion" picked up some comment lines
that were unrelated to the structure name.
the "connected other node to. . ." message when terminals of a
device are shorted. A long enough node name, especially one
created by concatenating hierarchy when flattening a cell, can
easily overrun the short 256-byte string buffer. Fixed by
changing strcat() to strncat().
natural sort instead of ASCII-based sorting, so that ports that
are numbered arrays will be indexed properly by count. Also:
Modified the "extresist" handling of substrate to draw the default
substrate type over the entire cell area (less areas of nwell or
other conflicting type). This allows extresist to extract the
entire substrate as a resistive network. The result is ugly and
may warrant some aggressive network simplification, but it should
at least be realistic.
that allocates and deallocates a single layer mask used by the
tech reader. Decided to work around the issue just by allocating
it only once and not releasing it---it's just a few bytes.
tech file "extract" section to work correctly when the offset is
negative. Generally, a negative offset is nonphysical and is just
curve-fitting round-off error, but the existing code was failing
to divide out the factor of 1000 that had been multiplied through
when reading the tech file, resulting in a very wrong offset.
isolate the terminal areas of a device (e.g., source and drain)
and calculate their area and perimeter individually for the
device (in addition to the traditional method of calculating
area and perimeter of each resistance class for the entire node).
Also: Reworked the SPICE syntax output to generate SI values
in the range 1-1000 with the appropriate suffix (e.g., "20u")
instead of defaulting to "u" for lengths and "p" for areas.
This prevents it from producing weird units like "150000u" when
a process definition already includes a scalefactor.
Reworked the "extresist" code to use the device terminal area
and perimeter. This fixes an error in which "extresist" would
lose these values and "ext2spice" with option "extresist on"
would generate a new netlist output with zero terminal areas
and perimeters.
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.
commit to prevent port labels from being copied up from the
flattened cell into the parent, and prefixing the instance
name to text in the instance top level so that there will be
no port or label collisions in the parent cell after flattening
the child cell in place. Also: Changed "extract dolabelcheck"
to be the default setting.
parameters l1 and l2. Provides a way to pass the source or drain
length as a parameter for, for example, an extended FET drain
implemented as a resistor abutting the FET gate. Could potentially
be used as a way to determine source/drain area and perimeter
without resorting to measurements of a shared node.
use of a resistor type as a FET extended drain, allowing the
FET drain node to short across to the other side of the resistor
so that the resistor is absorbed into the FET device. Used with
the GF180MCU process to describe the salicide-block ESD FET types.
library has been read in with the "gds readonly true" option set
because the cell contains information on where in the GDS the
cell is located, but the cell is empty because it was flattened
into the magic view and all of its contents were erased. This can
cause issues with LVS if magic generates an empty cell into the
netlist and the LVS tool tries to compare the cells by name. Also,
this prevents unnecessary .ext files and unnecessary merges to the
substrate of such cells (since all cells have an implied substrate).
respect to calculations around diode-connected diffusion regions.
The diffusion area calculation needed to be fixed to avoid double-
counting contacts, and the value for the ratioDiffA coefficient
needed to be scaled, since it is multiplied by the diffusion area
and therefore has dimensioned units of (1/area^2) and should be
treated like all other dimensioned units in magic.
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.
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.
tech files which incorrectly parses the syntax using five
parameters. This syntax variant does not get used often, which
is why the error went undetected for a long time.
run free() on a memory location that was never allocated. This
error has no effect on anything, but correcting it prevents magic
from issuing a mysterious warning.
caused by other code that can move the plane of a device to match
the plane of a port. Solved by retaining the original plane of the
node in the extTransRec structure, and using that to determine the
device plane for purposes of calculating perimeters and not double-
counting contacts.
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.
Tim Edwards
Johan Euphrosine
Sean Cross
Anton Blanchard
Alessandro De Laurenzis