SPICE and verilog, in spite of the syntactical differences, to
account for the trick that qflow uses to replace the trailing space
in a verilog backslash-escaped name with a second backslash to get
a SPICE-compatible name that can be easily converted back to its
original verilog name without loss of information. What this means
is that verilog can read SPICE files containing verilog names (which
is illegal SPICE) and verilog files containing hacked-backslash
names (which is illegal verilog). This should be mostly harmless
although the wisdom of it is surely questionable.
assignment statements in verilog netlists, including assignment of
signal bundles. Also corrected handling of signal bundles in pin
connections, which had been corrected in qflow's verilog parser but
not copied back to netgen. Note that the syntax for signals multiplied
N times is still not handled.
a "critical property". This lets a device define multiple critical
properties, all of which must match before additive properties can
be combined in the same device.
re-worked property command, "critical" properties must match
across devices so that all other properties can be combined as
specified (addition, parallel combination, or none). The code was
still based on the older notion of the "critical" property being
the one to add (and thus preventing multiple properties from being
added in different ways). This has now been fixed.
handle verilog syntax. Also: Added SPICE voltage and current
sources as separate classes (as opposed to being converted to
subcircuits, which was how they were previously handled). That
allowed voltage sources to be checked for zero value and removed
by shorting the ends together, as was being done for zero value
resistors (note that like zero-value resistors, removal is only
done if removing the component makes a better match than leaving
it in). In particular, yosys has SPICE netlist output that
converts equality assignments ("assign a = b") into zero-value
voltage sources, so these components need to be treated as
non-physical elements.
the possibility that a device (e.g., resistor or capacitor) may
not be a semiconductor device (in other words, a parasitic or
ideal device), and therefore uses "value" but not width and
length, and therefore "value" is a critical property to merge
both in series and parallel. Corrected the series/parallel
network optimization to prevent it from setting both M and S
records > 1 on the same device (which is ambiguous). To try
to get number of devices to match, where there are both series
and parallel devices, they will be merged across the critical
property early (before property matching).
accidentally erasing array delimiters from node names, a move that
surprisingly has no effect at all on LVS until the cell containing
the truncated nodes is flattened, at which point it causes odd and
confusing behavior that seems to have nothing to do with node names
at all.
Tim Edwards
Roman-Parise
Tim Edwards