Method for allocating spare cells in auto-place-route blocks
First Claim
1. A method for allocating spare cells in an auto-place-route (APR) block, comprising:
- calculating a total area of a list of functional cells and a list of spare cells to be included in the APR block;
providing said list of functional cells and a boundary as input to an auto-placement tool to generate a layout of the APR block based thereon, wherein said list of functional cells excludes said list of spare cells, wherein said boundary has an area approximately equal to said total area of said list of functional cells and said list of spare cells; and
substantially filling white space in said layout with spare cells from said list of spare cells.
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Abstract
A method for placing spare cells into an auto-place-route (APR) block of an integrated circuit is disclosed. The list of functional cells to be included in the block is determined along with the netlist. The sum of the areas of the functional cells and the desired spare cell area is used as the area of the block boundary. The boundary is provided as input to an auto-placement tool along with the netlist and the list of functional cells. The list of functional cells specifically does not include the spare cells so that the tool does not place spare cells in the boundary. Consequently, the spare cell area may be utilized as wiggle-room by the tool to efficiently place the functional cells. The tool produces a placement of the functional cells that includes white space in the boundary. Spare cells are then placed into the white space.
37 Citations
28 Claims
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1. A method for allocating spare cells in an auto-place-route (APR) block, comprising:
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calculating a total area of a list of functional cells and a list of spare cells to be included in the APR block;
providing said list of functional cells and a boundary as input to an auto-placement tool to generate a layout of the APR block based thereon, wherein said list of functional cells excludes said list of spare cells, wherein said boundary has an area approximately equal to said total area of said list of functional cells and said list of spare cells; and
substantially filling white space in said layout with spare cells from said list of spare cells. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for placing cells within an auto-place-route (APR) block in an integrated circuit, the APR block design including a functional cell list specifying a plurality of functional cells to be included therein, each of the plurality of functional cells having an area and inputs and outputs, the APR block design also including connectivity information specifying how said inputs and outputs of said plurality of functional cells is to be connected, the method comprising:
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determining a spare cell area;
determining a boundary of the APR block having an area approximately equal to a sum of said spare cell area and the plurality of functional cell areas;
providing to an APR software program the functional cell list, the connectivity information, and said boundary, wherein said APR program generates a layout of the APR block having empty space within said boundary; and
placing spare cells into said empty space after said APR program generates said layout of the APR block. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for placing cells within a functional block of an integrated circuit, comprising:
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determining a list of cells to be included in the functional block, said list excluding spare cells;
determining a boundary of the functional block, said boundary having an area which is a function of a sum of areas of said list of cells;
generating a physical placement of said list of cells within said boundary, wherein said physical placement is generated by auto-placement software, said auto-placement software receiving a specification of said boundary and said list of cells; and
placing spare cells into white space within said boundary after said generating said physical placement, wherein said white space is a result of said auto-placement software physical placement of said list of cells. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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Specification