Dummy block replacement for logic simulation

• US 7,330,808 B1
• Filed: 07/24/2003
• Issued: 02/12/2008
• Est. Priority Date: 07/24/2003
• Status: Expired due to Fees

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Sze, Walter N., Jorgensen, Vincent J.
• Primary Examiner(s): Rodriguez; Paul
• Assistant Examiner(s): Kim; Eunhee
• Application Number:
  US10/627,335
• Time in Patent Office: 1,664 Days
• Field of Search: 703 13- 14, 716/8, 716 9- 17
• US Class Current: 703/14
• CPC Class Codes: G06F 30/33 Design verification, e.g. functional simulation or model checking

Abstract

A method (10) of reducing a size of a netlist for a target architecture can include the steps of creating (12) a netlist of objects for the target architecture, identifying (14) objects specific to the target architecture that are repeated regularly to identify potential dummy objects, creating (15) a list of objects used by a design in the target architecture, and forming (16) a list of unused objects in the target architecture from the netlist of objects and the list of objects used by the design. The method can further include the steps of replacing (18) at least one object in the list of unused objects with an appropriate dummy object to form a modified netlist and simulating (19) the modified netlist.

Claims

1. A method of reducing a size of a netlist for a hardware target architecture for simulation, comprising:

create a netlist of objects specifying each object for the target hardware architecture, wherein the target hardware architecture is a field programmable gate array;

identify objects specific to the target hardware architecture that are repeated to identify potential dummy objects;

create a list of objects, from the netlist of objects, that are used by a circuit design to be implemented in the target hardware architecture;

form a list of unused objects in the target hardware architecture from the netlist of objects and the list of objects used by the circuit design;

replace at least one object in the netlist of objects for the target hardware architecture that is also specified in the list of unused objects and which is identified as a potential dummy object with an appropriate dummy object to form a modified netlist by removing functional hardware description language from the object; and

simulate the modified netlist by simulating each object of the modified netlist inclusive of each dummy object, wherein for each dummy object, a signal provided to the dummy object is fed through the dummy object unchanged.

2. The method of claim 1, wherein the step of forming the list of unused objects comprises the steps of subtracting the list of objects used by the circuit design from the netlist of objects.

3. The method of claim 1, wherein the step of replacing at least one object comprises the step of replacing objects in the netlist of objects for the target hardware architecture that are also specified in the list of unused objects that are repeated with the appropriate dummy objects to form the modified netlist.

4. The method of claim 1, wherein the step of replacing at least one object comprises the step of replacing each object in the netlist of objects for the target hardware architecture that is also specified in the list of unused objects with the appropriate dummy object to form the modified netlist.

5. The method of claim 1, wherein the step of forming the list of unused objects comprises the steps of parsing a file to extract a list containing object names for all used instances for the target hardware architecture and parsing the netlist for the target architecture.

6. The method of claim 1, wherein the step of replacing comprises replacing a type of an instance for an object found in the repeated list of objects with a type for a corresponding dummy object if the object found in the repeated list is not on the list containing object names for used objects.

7. The method of claim 1, wherein the method further comprises the step of parsing the netlist for the target hardware architecture line by line and forming a modified netlist with the appropriate dummy objects when all lines of the netlist have been parsed.

8. The method of claim 7, wherein the method further comprises the step of feeding through a signal unchanged when simulating the appropriate dummy object during a simulation process using the modified netlist.

9. The method of claim 1, wherein the step of forming the list of unused objects comprises the step of manually composing a list of repeated root objects specific to the target hardware architecture.

10. The method of claim 1, wherein the step of replacing comprises the step of emptying a hardware description language version of a repeated object to form an object devoid of an explicit functional mapping of an input to an output.

11. A method of processing signals with a modified netlist within a software-based logic simulation tool comprising the step of:

creating a netlist of objects specifying each object for a target hardware architecture, wherein the target hardware architecture is a field programmable gate array;

identifying objects specific to the target hardware architecture that are repeated to identify potential dummy object;

creating a list objects, from the netlist of objects, that are used by a circuit design to be implemented in the target hardware architecture;

forming a list of unused objects in the target hardware architecture from the netlist of objects and the list of objects used by the circuit design;

replacing any at least one object in the netlist of objects for the target hardware architecture that is also specified in the list of unused object and which is identified as a potential dummy object with an appropriate dummy object to form a modified netlist by removing functional hardware description language from the object; and

simulating the modified netlist by simulating each object of the modified netlist inclusive of each dummy object, wherein for each dummy object, a signal provided to the dummy object is fed through the dummy object unchanged.

12. The method of claim 11, wherein the method further comprises feeding through a signal unchanged when simulating the modified netlist inclusive of each dummy object.

13. A machine readable storage, having stored thereon a computer program having a plurality of code sections executable by a machine for causing the machine to perform the steps of:

create a netlist of objects specifying each object for a target hardware architecture, wherein the target hardware architecture is a field programmable gate array;

identify objects specific to the target hardware architecture that are repeated to identify potential dummy objects;

create a list of objects used by a circuit design to be implemented in the target hardware architecture;

form a list of unused objects in the target hardware architecture from the netlist of objects and the list of objects used by the circuit design;

replace at least one object in the netlist of the target hardware architecture that is also specified in the list of unused objects and which is identified as a potential dummy object with an appropriate dummy object to form a modified netlist by removing functional hardware description language from the object; and

simulate the modified netlist by simulating each object of the modified netlist inclusive of each dummy object, wherein for each dummy object, a signal provided to the dummy object is fed through the dummy object unchanged.

14. The machine readable storage of claim 13, wherein the computer program further has a plurality of code sections executable by the machine for causing the machine to perform the step of parsing the netlist for the target hardware architecture line by line and forming a modified netlist with one or more of the appropriate dummy objects when all lines of the netlist have been parsed.

15. A system for simulating a circuit design for target hardware architectures for implementation on field programmable gate arrays comprising:

means for creating a netlist of objects specifying each object for the target hardware architecture, wherein the target hardware architecture is a field programmable gate array;

means for identifying objects specific to the target hardware architecture that are repeated to identify potential dummy objects;

means for creating a list of objects used by the circuit design in the target hardware architecture;

means for forming a list of unused objects in the target hardware architecture from the netlist of objects and the list of objects used by the circuit design;

means for replacing at least one object in the netlist of the target hardware architecture that is also specified in the list of unused objects and which is identified as a potential dummy object with an appropriate dummy object to form a modified netlist by removing functional hardware description language from the object; and

means for simulating the modified netlist by simulating each object of the modified netlist inclusive of each dummy object, wherein for each dummy object, a signal provided to the dummy object is fed through the dummy object unchanged.

16. The system of claim 15, further comprising means for parsing the netlist for the target hardware architecture line by line and forming a modified netlist with a plurality of dummy objects when all lines of the netlist have been parsed.

17. The system of claim 15, wherein the system uses a Verilog version of a hardware description language.