.TH EXTCHECK 1
.SH NAME
extcheck \- check hierarchical \fIext\fR\|(5) files for global node
connectivity and summarize number of fets, nodes, etc.
.SH SYNOPSIS
.B extcheck
[
.B \-c
.I cthresh
] [
.B \-p
.I path
] [
.B \-r
.I rthresh
] [
.B \-s
\fIsym\fB=\fIvalue\fR
] [
.B \-C
] [
.B \-R
] [
.B \-S
.I symfile
] [
.B \-T
.I tech
]
.I root

.SH DESCRIPTION
\fIExtcheck\fR will read an extracted circuit in the hierarchical \fIext\fR\|(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 \fIroot\fB.ext\fR;
it and all the files it references are recursively flattened.
.PP
The following options are recognized:
.TP
.B \-c\ \fIcthresh\fP
Set the capacitance threshold to \fIcthresh\fP femtofarads.
\fIExtcheck\fR will count the number of explicit internodal capacitors
greater than \fIcthresh\fR, the number of nodes whose capacitance
is greater than \fIcthresh\fR, as well as the total number of
nodes.
(Other programs such as \fIext2sim\fR\|(1) use this
option as a threshold value below which a capacitor will not
be output).
The default value for \fIcthresh\fP is 10 femtofarads.
.TP
.B \-p\ \fIpath\fP
Normally, the path to search for \fB.ext\fP files is determined by
looking for \fBpath\fP commands in first ~cad/lib/magic/sys/.magic,
then ~/.magic, then .magic in the current directory.
If \fB\-p\fP
is specified, the colon-separated list of directories specified
by \fIpath\fP is used instead.
Each of these directories is searched
in turn for the \fB.ext\fP files in a design.
.TP
.B \-r\ \fIrthresh\fP
Set the resistance threshold to \fIrthresh\fP ohms.
Similar in function
to \fB\-c\fR, but for resistances.
The default value for \fIrthresh\fP is 10 ohms.
.TP
.B \-s\ \fIsym\fB=\fIvalue\fP
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 \fBext:w=\fIwidth\fB^\fR or \fBext:l=\fIlength\fB^\fR,
where \fIwidth\fR or \fIlength\fR can either be numeric, or textual.
(The trailing ``\fB^\fR'' indicates that these are transistor
gate attributes).
If textual, they are treated as symbols which can be assigned a numeric
value at the time \fIext2sim\fR is run.
The \fB\-s\fR 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 \fB\-s\fR
(or \fB\-S\fR below), then it is ignored; otherwise, the transistor's
length or width is set to the numeric value defined for that symbol.
\fI(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)\fR
.TP
.B \-C
Set the capacitance threshold to infinity.
Because this avoids any internodal capacitance processing,
all tools will run faster when this flag is given.
.TP
.B \-R
Set the resistance threshold to infinity.
.TP
.B \-S\ \fIsymfile\fP
Each line in the file \fIsymfile\fR is of the form \fIsym\fB=\fIvalue\fR,
just like the argument to the \fB\-s\fR flag above; the lines are interpreted
in the same fashion.
\fI(This option is not currently used by extcheck,
but it is common to ext2sim et. al.)\fR
.TP
.B \-T\ \fItech\fP
Set the technology in the output \fB.sim\fR file to \fItech\fP.
This overrides any technology specified in the root \fB.ext\fR file.

.SH "SEE ALSO"
ext2dlys\|(1), ext2sim\|(1), ext2spice\|(1), magic\|(1),
rsim\|(1), sim2spice\|(1), ext\|(5), sim\|(5)

.SH AUTHOR
Walter Scott

.SH BUGS
The \fB\-s\fR mechanism is incomplete; it should allow quantities other than
transistor lengths and widths to be specified.