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.\"  * $Source: /vol/opua/opua2/sis/sis-1.1/common/src/sis/sis_lib/help/RCS/read_pla.1,v $
.\"  * $Author: sis $
.\"  * $Revision: 1.3 $
.\"  * $Date: 1992/05/06 19:04:01 $
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.XX
read_pla [-a] [-s] [-c] filename
.PP
Read in an espresso-format PLA from the
file \fBfilename\fP (see espresso(5) for more
information).  The network name is derived
from the filename with any trailing extension removed.
.PP
Usual filename conventions apply: \fB-\fP (or no
filename) stands for standard input, and tilde-expansion is performed
on the filename.
.PP
Normal operation is to replace the current network with a single-level
network of complex gates with the same logic functions as the PLA outputs.
This makes each PLA output a separate single-output function and is
a good starting point for the standard scripts.
If don't care conditions exist, the external
don't care network is also replaced with a single-level network
which implements the don't care conditions of the PLA.
Otherwise, the external don't care network is set to NIL (nonexistent).
.PP
The \fB-c\fP option replaces the current network with 
a two-level network of NOR-gates (and inverters)
which implements the PLA.
This preserves the multiple-output nature of the PLA.
The external don't care network is manipulated exactly the same as above.
This used to be the default, while the \fB-s\fP option
replaced the network with a single-level network as described above.
The \fB-s\fP option has been retained for compatibility.
.PP
The \fB-a\fR option specifies that the new network should be appended to the
current network.
Functions are associated between the two networks
using the long names of each network.
Name conflicts (two
functions attempt to define the same name) generate warning messages
and are resolved by renaming the signal from the new network.
