We are going to use for all the examples the GDSII file known as demo8.gds. The top structure of this file is TOPMSPCHIP1. It is about 28MB in size. For simplicity I am going to remove long paths to the file and to the program. The working directory will be /home/stevedb/demo8. The program directory is /home/cad/gds_extents/bin.
Find all the placements of cell: G79S11F36 relative to the top cell
gds_extents demo8.gds example1 = = -cell_extents G79S11F36
This will produce an ascii file named: example1.extents.txtcontaining the following:
REF Extents: G79S11F36 -4848.650,493.150,-4595.450,632.850 -4848.650,2100.000,-4595.450,2239.700 -4848.650,4320.500,-4595.450,4460.200 -3446.100,-4739.300,-3306.400,-4486.100 -2909.950,4486.100,-2770.250,4739.300 -2146.450,-4739.300,-2006.750,-4486.100 -1436.350,4486.100,-1296.650,4739.300 -998.050,-4739.300,-858.350,-4486.100 262.900,4486.100,402.600,4739.300 472.700,-4739.300,612.400,-4486.100 1566.300,4486.100,1706.000,4739.300 1802.900,-4739.300,1942.600,-4486.100 3616.650,4486.100,3756.350,4739.300 4595.400,-4095.650,4848.600,-3955.950 4595.400,-2436.100,4848.600,-2296.400 4595.400,-1225.000,4848.600,-1085.300 4595.400,-150.950,4848.600,-11.250 4595.400,1373.250,4848.600,1512.950 4595.400,2881.250,4848.600,3020.950
These coordinates are the LL and UR corners of rectangles that represent the placements of G79S11F36 in the cell TOPMSPCHIP1. If you want to generate a GDSII file with the same information just add the command line argument -gds.
gds_extents demo8.gds example1 = = -cell_extents G79S11F36 -gds
You can see from the screen shot below that the resulting GDSII output shows 19 placements of G79S11F36 (blue) and the extents of the top level cell is shown in red.
Find the placements for a bunch of different cellsYou are given a list of cells that you need to know where they are placed. The list looks like:
G79S0F36 G79S3F36 G79S6F36 G79S9F36 G79S1F36 G79S4F36 G79S7F36 G79S10F36 G79S2F36 G79S5F36 G79S8F36 G79S11F36
In this case you do not want to put a long list on the command line; instead you can use a response file such as cells.txt. By preceding the response file with the @ sign the program knows this is a file that should be opened and processed.The response file cells.txt looks like:
G79S0F36 G79S1F36 G79S2F36 G79S3F36 G79S4F36 G79S5F36 G79S6F36 G79S7F36 G79S8F36 G79S9F36 G79S10F36 G79S11F36
and the command line looks like this:
gds_extents demo8.gds example2 = = -cell_extents @cells.txt
The ascii file will now have entries for each of the cells in the list ... I cannot show the entire list but you can see how it is formatted below. If you create GDSII using the -gds command line argument you will see that all of the IO cells seem to be included in this list.
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