Rule based floorplanner

• US 5,311,443 A
• Filed: 08/13/1992
• Issued: 05/10/1994
• Est. Priority Date: 08/13/1992
• Status: Expired due to Fees

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Crain, Steven L., Burkis, Joseph J., Cowan, Andrew H., Lutz, Martin F.
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US07/928,573
• Time in Patent Office: 635 Days
• Field of Search: 364/488, 364/489, 364/490, 364/578, 395/919, 395/920, 395/921, 395/922, 395/923
• US Class Current: 716/122
• CPC Class Codes: G06F 30/392 Floor-planning or layout, e.g. partitioning or placement
• CPC Class Codes: Y10S 706/921 Layout, e.g. circuit, construction

Abstract

A rule based floorplanner for a macrocell array having a plurality of predetermined macrocells. The floorplanner uses a net list (23), a macrocell list (26), and a list of design constraints (31) and characteristics of the base array itself to derive an initial Burain score. A trial floorplan is attempted (33) and checked against a list of theoretical rules (39) and a list of empirical rules (38) to determine a measured Burain score (36) which accurately indicates the difficulty which can be expected when completing the design.

Claims

1. A rule based floorplanner, comprising:

a net list defining a plurality of desired connections between the macrocells;

a plurality of macrocell groups defined among the plurality of predetermined macrocells, the macrocell groups being located within the macrocell array so as to satisfy a set of predetermined design constrains which constrain later placement of the macrocells;

a theoretical rule for predicting routability of the macrocell array;

a measured rule for predicting routability of the macrocell array; and

a Burain score for the macrocell array based on the macrocell groups, the theoretical rule, and the measured rule applied to the macrocell groups as placed within the macrocell array.

2. The rule based floorplanner of claim 1 further comprising:

an initial Burain score, wherein a plurality of components of the measured rule which are unique to the particular design are derived entirely from the net list.

3. The rule based floorplanner of claim 1 further comprising:

a graphical indicator used to mark each macrocell group which is in violation of a predetermined constraint.

4. The rule based floorplanner of claim 1 further comprising:

editing means whereby the macrocell group is defined, modified and positioned within the macrocell array.

5. The rule based floorplanner of claim 1 further comprising:

display means for graphically showing a predetermined plurality of parameters affecting the theoretical rule and the measured rule.

6. The rule based floorplanner of claim 1 further comprising:

fast global routing means for determining global route congestion; and

a rule which utilizes global route congestion as a parameter.

7. The rule based floorplanner of claim 6 further comprising:

congestion map display means for displaying global route congestion.

8. A method for rule based floorplanning, comprising:

providing a plurality of predetermined macrocells which make up a predetermined macrocell array;

compiling a macrocell physical property list comprising the physical properties for each of the macrocells;

defining a plurality of desired connections between the macrocells within a net list;

defining a plurality of macrocell groups among the plurality of predetermined macrocells each group comprising macrocells for which physical proximity is desired based on an analysis of the physical property list and the net list;

manually locating the macrocell groups within the macrocell array so as to satisfy a set of predetermined design constrains which constrain later placement of the macrocells during the physical design process;

compiling a theoretical rule for predicting routability of the macrocell array;

compiling a measured rule for predicting routability of the macrocell array;

computing a Burain score for the macrocell array based on the macrocell layout list, the theoretical rule, and the measured rule as applied to the macrocell groups as placed within the macrocell array; and

modifying the structure, composition, and location of at least one macrocell group to improve the Burain score.

9. The method for rule based floorplanning of claim 8, further comprising:

deriving a final floorplan based on the optimal group locations; and

directly linking the final floorplan to at least one physical design tool which is used to create a predetermined design.

10. The method for rule based floorplanning of claim 8, further comprising:

deriving information which is unique to a predetermined design from the net list; and

computing an initial Burain score before defining macrocell groups.

11. A rule based floorplanner, comprising:

a macrocell array having a plurality of predetermined macrocells;

a net list defining a plurality of desired connections between the macrocells;

editing means whereby a plurality of macrocell groups are defined, modified and positioned within the macrocell array so as to satisfy a set of predetermined design constrains which restrain later placement of the macrocells during physical design;

a macrocell list comprising layout related properties for each of the macrocells;

a plurality of theoretical rules for predicting routability of the macrocell array based on theoretical analysis of the macrocell array and physical design constrains;

a plurality of measured rules based on past designs for predicting routability of the macrocell array;

a Burain score for the macrocell array based on the macrocell list, the theoretical rules, and the measured rules as applied to the macrocell groups as placed within the macrocell array;

congestion map display means for displaying global route congestion together with fixed routing barriers;

a final floorplan based on the optimal macrocell groups; and

linking means for directly linking the final floorplan to at least one physical design tool.