extcheck - check hierarchical ext(5) files for global node
connectivity and summarize number of fets, nodes, etc.
extcheck [ -c cthresh ] [ -p
path ] [ -r rthresh ] [ -s
sym=value ] [ -C ] [ -R ] [ -S
symfile ] [ -T tech ] root
Extcheck will read an extracted circuit in the hierarchical
ext(5) representation produced by Magic, check to ensure that all
global nodes (those to which a label ending in an exclamantion point is
attached) are fully connected in the layout, and then print a count of the
number of various items (nodes, fets, etc) encountered while flattening the
circuit. The root of the tree to be processed is the file
root.ext; it and all the files it references are recursively
flattened.
The following options are recognized:
- -c cthresh
- Set the capacitance threshold to cthresh femtofarads.
Extcheck will count the number of explicit internodal capacitors
greater than cthresh, the number of nodes whose capacitance is
greater than cthresh, as well as the total number of nodes. (Other
programs such as ext2sim(1) use this option as a threshold value
below which a capacitor will not be output). The default value for
cthresh is 10 femtofarads.
- -p path
- Normally, the path to search for .ext files is determined by
looking for path commands in first ~cad/lib/magic/sys/.magic, then
~/.magic, then .magic in the current directory. If -p is specified,
the colon-separated list of directories specified by path is used
instead. Each of these directories is searched in turn for the .ext
files in a design.
- -r rthresh
- Set the resistance threshold to rthresh ohms. Similar in function
to -c, but for resistances. The default value for rthresh is
10 ohms.
- -s sym=value
- It's possible to use special attributes attached to transistor gates to
control the length and width of transistors explicitly, rather than
allowing them to be determined by the extractor. These attributes are of
the form ext:w=width^ or
ext:l=length^, where width or length
can either be numeric, or textual. (The trailing ``^'' indicates
that these are transistor gate attributes). If textual, they are treated
as symbols which can be assigned a numeric value at the time
ext2sim is run. The -s flag is used to assign numeric values
to symbols. If a textual symbol appears in one of the above attributes,
but isn't given a numeric value via -s (or -S below), then
it is ignored; otherwise, the transistor's length or width is set to the
numeric value defined for that symbol. (This option is not currently
used by extcheck, but it is common to ext2sim(1) and other
tools that are written using the extflat(3) library)
- -C
- Set the capacitance threshold to infinity. Because this avoids any
internodal capacitance processing, all tools will run faster when this
flag is given.
- -R
- Set the resistance threshold to infinity.
- -S symfile
- Each line in the file symfile is of the form
sym=value, just like the argument to the -s
flag above; the lines are interpreted in the same fashion. (This option
is not currently used by extcheck, but it is common to ext2sim et.
al.)
- -T tech
- Set the technology in the output .sim file to tech. This
overrides any technology specified in the root .ext file.
The -s mechanism is incomplete; it should allow quantities
other than transistor lengths and widths to be specified.