By default this command distributes and places all

By default, this command distributes and places all the spare cells evenly throughout the
core area.
You can specify the spare cells to place by using one of the following two methods:
❍
To place specific spare cells, use the
-cells
option.
❍
To place all the spare cells that belong to specific voltage areas, use the
-voltage_areas
option.
You can specify an area within which to place the spare cells by using the
-boundary
option.
2. Legalize the spare cells by using the
place_eco_cells –legalize_only –cells
command.
The following example places all spare cells within a specified boundary and legalizes them:
icc2_shell> spread_spare_cells -boundary {{100 150} {650 500}}
icc2_shell> place_eco_cells -legalize_only \
-cells [get_cells -hierarchical spares*]

Chapter 11: ECO Flow
Automatically Adding Spare Cells 11-10
IC Compiler™ II Implementation User Guide L-2016.03-SP4
IC Compiler™ II Implementation User Guide Version L-2016.03-SP4
Automatically Adding Spare Cells
You can add and place spare cells to a legalized design by using the
add_spare_cells
command after you perform placement and optimization.
When you use this command, you must specify the following information:
• A name prefix for the spare cells by using the
-cell_name
option
• The type and number of spare cells to insert by using one of the following two methods:
❍
Specify the library cells to use for the spare cell and the number of instances of each
library cell by using the
-lib_cell
and
-num_instances
options
For example, to insert 250 instances each of the AND2 and OR2 library cells, use the
following command:
icc2_shell> add_spare_cells -cell_name spare1 \
-lib_cell {AND2 OR2} -num_instances 250
❍
Specify the library cells and a different number of instances for each library cell by
using the
-num_cells
option
For example, to insert 200 instances of the NAND2 library cell and 150 instances of
the NOR2 library cell, use the following command:
icc2_shell> add_spare_cells -cell_name spare2 \
-num_cells {NAND2 200 NOR 150}
By default, the command distributes the spare cells evenly throughout the design. However,
you can control the distribution of the spare cells by using one of the following three
methods:
• To distribute the spare cells within a specific hierarchical block, use the
-hier_cell
option.
When you use this option, the tool distributes the spare cells in a rectangular area that
encloses all of the cells that belong to the specified hierarchical block.
• To distribute the spare cells within a specific bounding box, use the
-boundary
option.
• To distribute the spare cells within specific voltage areas, use the
-voltage_areas
option.
The
add_spare_cells
command places spare cells, but does not legalize them. To legalize
these cells, use the
place_eco_cells -legalize_only -cells
command.

Chapter 11: ECO Flow
Adding Programmable Spare Cells 11-11
IC Compiler™ II Implementation User Guide Version L-2016.03-SP4
The following example adds spare cells using the
add_spare_cells
command and
legalizes them:
icc2_shell> add_spare_cells -lib_cell {INV} -num_instances 400 \
-cell_name spares