Timing verification method and timing verification apparatus

1. A timing verification method, comprising:

performing, using a computer, timing analysis taking a voltage drop of a laid out circuit into consideration; and

producing, using a computer, a changing instruction list for changing the laid out circuit based on a result of the timing analysis; wherein,

in a first-time timing verification process performed by a computer, voltage drop analysis is performed for the laid out circuit and a voltage drop list is produced based on a result of the voltage drop analysis, and then the timing analysis is performed using the voltage drop list; and

in all or part of a second-time and later timing verification process performed by a computer, the voltage drop list is updated based on the changing instruction list without performing the voltage drop analysis and the timing analysis is performed using the updated voltage drop list.

2. The timing verification method as claimed in claim 1 , further comprising:

producing, using a computer, an arrangement wiring database based on a result of a layout process;

updating, using a computer, the arrangement wiring database based on the result of the layout process based on the changing instruction list; and

updating, using a computer, the voltage drop list using the updated arrangement wiring database based on the changing instruction list.

3. The timing verification method as claimed in claim 1 , further comprising:

producing, using a computer, an arrangement wiring database based on a result of a layout process;

updating, using a computer, the arrangement wiring database based on the a result of a layout process based on the changing instruction list;

producing, using a computer, a voltage drop map wherein position information of blocks obtained by dividing a chip such that each of the blocks includes a plurality of cells and voltage drop information are associated with each other based on a result of the voltage drop analysis; and

updating, using a computer, the voltage drop list using the updated arrangement wiring database and the voltage drop map based on the changing instruction list.

4. The timing verification method as claimed in claim 1 , further comprising:

producing, using a computer, a voltage drop map wherein position information of blocks obtained by dividing a chip such that each of the blocks includes a plurality of cells and voltage drop information are associated with each other based on a result of the voltage drop analysis; and

updating, using a computer, the voltage drop list using the voltage drop map based on the changing instruction list.

5. The timing verification method as claimed in claim 1 , further comprising:

producing, using a computer, a list wherein instance names and voltage values after voltage drop are associated with each other as the voltage drop list;

producing, using a computer, a list wherein instance names and changing instruction information are associated with each other as the changing instruction list; and

updating, using a computer, the voltage drop list using the instance names and changing instruction information included in the changing instruction list.

6. The timing verification method as claimed in claim 2 , further comprising:

producing, using a computer, a list wherein instance names and voltage values after voltage drop are associated with each other as the voltage drop list;

producing, using a computer, a list wherein instance names and changing instruction information are associated with each other as the changing instruction list;

producing, using a computer, the arrangement wiring database as a database wherein instance names and position information are associated with each other; and

updating, using a computer, the voltage drop list using the instance names and changing instruction information included in the changing instruction list and the position information included in the arrangement wiring database.

7. The timing verification method as claimed in claim 3 , further comprising:

producing, using a computer, a list wherein instance names and voltage values after voltage drop are associated with each other as the voltage drop list;

producing, using a computer, a list wherein instance names and changing instruction information are associated with each other as the changing instruction list;

producing, using a computer, the arrangement wiring database as a database wherein instance names and position information are associated with each other; and

updating, using a computer, the voltage drop list using the instance names and changing instruction information included in the changing instruction list, the position information included in the arrangement wiring database, and the position information of the blocks and voltage drop information included in the voltage drop map.

8. The timing verification method as claimed in claim 4 , further comprising:

producing, using a computer, a list wherein instance names and voltage values after voltage drop are associated with each other as the voltage drop list;

producing, using a computer, a list wherein instance names and changing instruction information are associated with each other as the changing instruction list;

producing, using a computer, a map wherein instance names, the position information of the blocks and the voltage drop information are associated with each other as the voltage drop map; and

updating, using a computer, the voltage drop list using the instance names and changing instruction information included in the changing instruction list and the instance names and voltage drop information included in the voltage drop map.

9. A timing verification program embodied on a non-transitory computer-readable medium and causing a computer to execute:

performing timing analysis taking a voltage drop of a laid out circuit into consideration; and

producing a changing instruction list for changing the laid out circuit based on a result of the timing analysis; wherein

in a first timing verification process, voltage drop analysis is performed for the laid out circuit and a voltage drop list is produced based on a result of the voltage drop analysis, and then timing analysis is performed using the voltage drop list; and

in all or part of a second-time and later timing verification process, the voltage drop list is updated based on the changing instruction list without performing the voltage drop analysis and timing analysis is performed using the updated voltage drop list.

10. The timing verification program embodied on a non-transitory computer-readable medium as claimed in claim 9 , wherein the timing verification program causes the computer to further execute:

producing an arrangement wiring database based on a result of a layout process;

updating the arrangement wiring database based on a result of the layout process based on the changing instruction list; and

updating the voltage drop list using the updated arrangement wiring database based on the changing instruction list.

11. The timing verification program embodied on a non-transitory computer-readable medium as claimed in claim 9 , wherein the timing verification program causes the computer to further execute:

producing an arrangement wiring database based on a result of a layout process;

updating the arrangement wiring database based on a result of the layout process based on the changing instruction list;

producing a voltage drop map wherein position information of blocks obtained by dividing a chip such that each of the blocks includes a plurality of cells and voltage drop information are associated with each other based on a result of the voltage drop analysis; and

updating the voltage drop list using the updated arrangement wiring database and the voltage drop map based on the changing instruction list.

12. The timing verification program embodied on a non-transitory computer-readable medium as claimed in claim 9 , wherein the timing verification program causes the computer to further execute:

producing a voltage drop map wherein position information of blocks obtained by dividing a chip such that each of the blocks includes a plurality of cells and voltage drop information are associated with each other based on a result of the voltage drop analysis; and

updating the voltage drop list using the voltage drop map based on the changing instruction list.

13. A timing verification apparatus, comprising:

a voltage drop analysis part performing voltage drop analysis for a laid out circuit;

voltage drop list production part producing a voltage drop list based on a result of the voltage drop analysis;

timing analysis part performing timing analysis;

a list producing part producing a changing instruction list for changing the laid out circuit based on a result of the timing analysis; and

voltage drop list updating part updating the voltage drop list based on the changing instruction list; wherein

said timing analysis part performs, in a first-time process, the voltage drop analysis by said voltage drop analysis part and timing analysis using the voltage drop list produced by said voltage drop list production part and performs, in all or part of a second-time and later process, timing analysis using the voltage drop list updated by said voltage drop list updating part without performing the voltage drop analysis by said voltage drop analysis part.

14. The timing verification apparatus as claimed in claim 13 , further comprising:

a database producing part producing an arrangement wiring database based on a result of a layout process; and

a database updating part updating the arrangement wiring database based on a result of a layout process based on the changing instruction list; and wherein

said voltage drop list updating part updates the voltage drop list using the updated arrangement wiring database based on the changing instruction list.

15. The timing verification apparatus as claimed in claim 13 , further comprising:

a database producing part producing an arrangement wiring database based on a result of a layout process;

a database updating part updating the arrangement wiring database based on a result of a layout process based on the changing instruction list; and

a map producing part producing a voltage drop map wherein position information of blocks obtained by dividing a chip such that each of the blocks includes a plurality of cells and voltage drop information are associated with each other based on a result of the voltage drop analysis; and wherein

said voltage drop list updating part updates the voltage drop list using the updated arrangement wiring database and the voltage drop map based on the changing instruction list.

16. The timing verification apparatus as claimed in claim 13 , further comprising:

a map producing part producing a voltage drop map wherein position information of blocks obtained by dividing a chip such that each of the blocks includes a plurality of cells and voltage drop information are associated with each other based on a result of the voltage drop analysis; and wherein

said voltage drop list updating part updates the voltage drop list using the voltage drop map based on the changing instruction list.