Interactive circuit designing apparatus which displays a result of component placement and wire routing from a layout design unit

• US 6,240,541 B1
• Filed: 01/11/1999
• Issued: 05/29/2001
• Est. Priority Date: 04/07/1995
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yasuda, Mitsuru, Kato, Yoshiyuki, Ito, Noriyuki, Sugiyama, Hiroyuki, Ikeda, Hiroshi, Abe, Yasunori, Takagi, Miki, Maruyama, Terunobu, Isomura, Tomoyuki, Yamashita, Ryoichi, Konno, Tadashi, Bizen, Naomi
• Primary Examiner(s): POWELL, MARK R
• Assistant Examiner(s): POWELL, MARK R
• Application Number:
  US09/227,967
• Time in Patent Office: 869 Days
• Field of Search: 395/500.07, 395/500.09, 395/500.03, 395/500.08, 395/500.1, 395/500.13, 395/500.12, 395/500.02, 716/1, 716/2, 716/6, 716/8, 716/7, 716/11, 716/12
• US Class Current: 716/112
• CPC Class Codes: G06F 30/33 Design verification, e.g. functional simulation or model checking

Abstract

A circuit designing apparatus of an interactive type which enables a simplified and highspeed circuit design process while largely reducing a burden on a designer, having a speed analyzing unit for conducting a delay computation for each wiring path on a circuit to be designed and a display control unit for displaying a result of the delay computation by the speed analyzing unit on a display unit. When the speed analyzing unit conducts a delay computation, a delay value of each logic component forming the circuit that is an object of the design is set and altered according to a dullness of a signal waveform inputted to the logic component. The circuit designing apparatus of an interactive type may be applied to a system for conducting a circuit design of an integrated circuit such as an LSI or the like or a printed circuit board.

Claims

1. A circuit designing apparatus of an interactive type having a display unit for displaying circuit design steps and an input unit for inputting responsive information to displayed data on said display unit and information necessary for a circuit design in order to conduct said circuit design in an interactive form comprising:

a layout design unit for conducting a placement in mounting of each of logic components composing a circuit that is an object of a design on the basis of a result of a logic design and wiring between said logic components;

a display control unit for causing said display unit to display a result of the placement and the wiring conducted by said layout design unit; and

a placing position determining unit for determining a placing position on a boundary of each layout hierarchy block in which a virtual block terminal is placed whenever said layout design unit divides a region that is an object of a design into plural layout hierarchy blocks to conduct a wiring design,

said placing position determining unit determining a center of gravity of coordinates of pins that are logic components linked to a net connected to a virtual block terminal in a layout hierarchy block in which a placing position of said virtual block terminal should be determined, determining a side of said layout hierarchy block which a straight line extending from a position of said center of gravity toward another layout hierarchy block that should be connected to said virtual block terminal crosses, determining a pin of said net closest to said side, and determining a position at which a straight line extending from a position of said pin in a main wiring direction or a sub wiring direction and said side cross as a placing position of said virtual block terminal,

said layout design unit conducting a wiring process between said plural layout hierarchy blocks while placing said virtual block terminal in the placing position determined by said placing position determining unit.

2. A circuit designing apparatus of an interactive type having a display unit for displaying circuit design steps and an input unit for inputting responsive information to displayed data on said display unit and information necessary for a circuit design in order to conduct said circuit design in an interactive form comprising:

a layout design unit for conducting a placement in mounting of each of logic components composing a circuit that is an object of a design on the basis of a result of a logic design and wiring between said logic components;

a display control unit for causing said display unit to display a result of the placement and the wiring conducted by said layout design unit; and

a placing position determining unit for determining a placing position on a boundary of each of layout hierarchy blocks in which a virtual block terminal is placed whenever said layout design unit divides a region that is an object of a design into plural layout hierarchy blocks to conduct a wiring design,

said placing position determining unit determining a center of gravity of coordinates of pins that are logic components linked to a net connected to said virtual block terminal in each of said layout hierarchy blocks connected to one another, connecting centers of gravity determined in respective layout hierarchy blocks with one another with a Steiner tree to estimate wiring paths, and determining positions in each of said estimated wiring path and a boundary of said layout hierarchy block cross as a placing position of a virtual bock terminal of each of said layout hierarchy blocks,

said layout design unit conducting a wiring process among said plural layout hierarchy blocks while placing said virtual block terminals in the respective placing positions determined by said placing position determining unit.

3. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein when said display unit displays a floor plan representing both positions of one or more logic components in the multiple components and routes of one or more wires interconnecting between pins of the one or more components in the predetermined area of the substrate in terms of characteristic points and lines interconnecting the characteristic points, said display control unit is operable;

(i) to select the pins of the one or more components as the characteristic points,

(ii) to decide a first coordinate value of each characteristic point for each coordinate of a coordinate system according to the positions of the one or more components in the predetermined area,

(iii) to sort the characteristic points in ascending or descending order of the first coordinate values of the characteristic points for each coordinate,

(iv) to substitute the first coordinate value of each characteristic point with a second coordinate value proportional to a rank of each characteristic point in the ascending or descending order of the first coordinate values for each coordinate, and

(v) to cause said display unit to display the characteristic points and the lines interconnecting between the characteristic points in the coordinate system using the second coordinate value of each characteristic point for each coordinate.

4. An interactive circuit designing apparatus according to claim 3, wherein said display control unit is operable to select at least one of an end-point and an internally dividing point of the one or more wires also as the characteristic points.

5. An interactive circuit designing apparatus according to claim 3, wherein when the predetermined area has a plurality of layers in which the multiple wires are to be routed, said display control unit is operable to calculate a third coordinate value of each characteristic point for each coordinate by adding a predetermined offset value to the second coordinate value of each characteristic point n times when the last-named characteristic point exists in the n-th layer from a predetermined one of the bottom and the top of the plural layers, and to cause said display unit to display the charate ristic points and the lines interconnecting the characteristic points in the coordinate system using the third coordinate value of each characteristic point for each coordinate.

6. An interactive ircuit designing apparatus according to claim 3, wherein said display control unit is operable to assign an identifier to each characteristic point before substitution of coordinate values, and to cause said display unit to display the characteristic points while designating each characteristic point by the same identifier before and after the substitution of coordinate values.

7. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting between at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect between pins of the multiple components placed bv said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data including both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner;

wherein said layout design unit further includes;

(iii) a wiring route estimating unit for estimating a result of the routing in said routing unit by routing a multiplicity of provisional wires between the pins of the multiple components based on a result of the placement of the multiple components by said placing unit, and

(iv) a congestion degree estimating unit for estimating a congestion degree of the multiple wires of the object circuit for each of local subareas of the predetermined area based on a result of the estimation by said wiring route estimating unit, and

said routing unit is operable to determine a routing order of the multiple wires and a roundabout rate for routing each wire based on the congestion degree estimated for each local subarea by said congestion degree estimating unit, and then to carry out the routing of the multiple wires according to both the routing order and the roundabout rate.

8. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin and a multipilicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein said layout design unit further includes a wiring route estimating unit for estimating a result of the routing in said routing unit by routing a multiplicity of provisional wires between the pins of the multiple components based on a result of the placement of the multiple components by said placing unit,

wherein said routing unit is operable to determine a routing order of the multiple wires and a roundabout rate of the routing based on a result of estimation by said wiring route estimating unit, and then to carry out the routing of the multiple wires according to both the routing order and the roundabout rate, and

wherein said layout design unit further includes a congestion degree estimating unit for estimating a congestion degree of the multiple wires of the object circuit by;

(i) dividing the predetermined area of the substrate into a multiplicity of squares arranged in a checkerboard pattern,

(ii) assigning to each of the multiple squares one or more channels available for the routing of the multiple wires,

(iii) counting the number of channels used for the routing of the multiple provisional wires among the available channels of each square based on a result of the estimation by said wiring route estimating unit,

(iv) estimating the congestion degree for each square by a proportion of the number of the used channels to the number of the available channels for each square, and

(v) ranking the multiple squares according to the congestion degree for each square, and said routing unit is operable to assign to each square a relative priority proportional to a rank of each square according to the congestion degree, and to carry out the routing of the multiple wires in the multiple squares according to the priority assigned for each square.

9. An interactive circuit designing apparatus according to claim 8, wherein when the predetermined area has a plurality of layers in which the multiple wires are to be routed,

said wiring route estimating unit is operable to carry out the estimation of the result of the routing for each of the plural layers,

said congestion degree estimating unit is operable to carry out the estimation of the congestion degree based on a result of the estimation for each layer by said wiring route estimating unit, and

said routing unit is operable to carry out the routing of the multiple wires with giving high priorities to wires using a channel in a square having a high congestion degree based on the congestion degree estimated for each wiring layer by said congestion degree estimating unit.

10. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein said layout design unit further includes a wiring route estimating unit for estimating a result of the routing in said routing unit by routing a multiplicity of provisional wires between the pins of the multiple components based on a result of the placement of the multiple components by said placing unit,

wherein said routing unit is operable to determine a routing order of the multiple wires and a roundabout rate of the routing based on a result of estimation by said wiring route estimating unit, and then to carry out the routing of the multiple wires according to both the routing order and the roundabout rate,

wherein said layout design unit further includes a routability judging unit for judging a routability of the multiple wires with a predetermined roundabout rate based on the estimation by said wiring route estimating unit, and

wherein said routing unit is operable to redetermine a roundable rate with which the multiple wires is assumed to be routable when said routability judging unit has judged unroutable with the predetermined roundabout rate.

11. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routine the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed bv said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein when the predetermined area has a plurality of layers in which the multiple wires are to be routed and each ofthe plural layers has a specific wiring direction in which wires are to be routed, said routing unit is operable to assign different ranges of wire length respectively to layers having a same wiring direction, and to carry out the routing of the multiple wires in the plural layers according to the wiring direction and the ranges of wire lengths.

12. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting between at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect between pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit which data including both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appronriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner;

wherein said routing unit is operable

(i) to calculate a critical degree for each of the multiple wires based on a predetermined delay value of each wire;

(ii) to classify the multiple wires according to the critical degree calculated for each wire,

(iii) to determine a routing order of the multiple wires and a roundable rate for routing of each wire based on the classification of the multiple wires according to the critical degree of each wire, and

(iv) to carry out the routing of the multiple wires according to the routing order and the roundabout rate.

13. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit,

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein said routing unit is operable to classify the multiple wires to be routed according to a critical degree to a delay value of each of the multiple wires, to determine a routing order of the multiple wires and a roundable rate for each wire, and to carry out the routing of the multiple wires according to the routing order and the roundabout rate, and

wherein said layout design unit is operable to set a wiring tolerable degree of one wire according to the critical degree for another wire which is to be routed adjacent to the one wire prior to the routing of the one wire, and to carry out the routing of the one wire according to the wiring tolerable degree after the routing of the one wire.

14. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting between at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data including both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner;

wherein said layout design unit further includes a placement check unit for checking whether there is any error component, which causes a placement error, among the multiple components based on a result of the placement of the multiple components by said placement unit, and

when one or more error components are found during the checking by said placement check unit, said display control unit is operable to control said display unit such that said display unit displays both a list of the error components and a placement map of the object circuit, which placement map represents the placement result of the multiple components by said placement unit, and to highlight one or more parts of the placement map displayed on said displayed unit, said parts corresponding to the one or more error components.

15. An interactive circuit designing apparatus according to claim 14, wherein when said input unit inputs an instruction to select one of the error components included in the list, said display control unit is operable to highlight the selected error component on said placement map.

16. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a disolay control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein said layout design unit further includes a congestion degree computing unit for dividing the predetermined area into a plurality of local subareas and computing a congestion degree of the multiple wires in each of the plural local subareas of the predetermined area based on the result of routing of the multiple wires by said routing unit, and

when said input inputs an instruction to re-route a selected one of the multiple wires while adding a specified length to a current wire length of the selected wire after the routing of the multiple wires by said routing unit, said routing until is operable to select a local subarea across which the selected wire is routed and which has a low congestion degree among the plural local subareas based on a result of the computation by said congestion degree computing unit, and to automatically carry out the re-routing of the selected wire while adding the specified length within the selected subarea.

17. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting between at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit which data including both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner;

wherein after the routing of the multiple wires is carried out by said routing unit and when said input unit inputs data selecting one of the multiple wires which is to be re-routed, data specifying a length which is to be added to a current wire length of the selected wire, and data specifying a local subarea of the predetermined area within which area the selected wire is to be re-routed, said routing unit is operable to automatically carry out the re-routing of the selected wire within the selected subarea while adding the specified length to the current wire length of the selected wire.

18. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting between at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit which data including both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various information necessary for circuit designing in response to the current data displayed be said display unit, thereby allowing circuit designing to be carried out in an interactive manner;

wherein when said input unit inputs an instruction to replace a selected one ofthe multiple components in a specified position on the predetermined area after the placement of the selected component by said placing unit and the routing of one or more wires associated with the selected component are carried out, said associated wires interconnecting between the selected component and one or more other components by said routing unit,

said placing unit is operable to replace the selected component in the specified position according to the instruction, and

said routing unit is operable to automatically re-route the associated wires in accordance with the specified position in which the selected component is replaced by said placing unit.

19. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetennined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting between at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data including both a result of placement by said placing unit and a result of routing by said routing unit;

(II) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner;

wherein said display unit is operable to display a plurality of placement maps each representing a part of the placement result of the multiple components by said placement unit, and

when one or more components included in a selected one of the plural placement maps are replaced by said placing units, or one or more wires included in the selected map are re-routed by said routing unit, in response to an external instruction through said input unit, said display control unit is operable to automatically renew both the selected map and any other one or more maps each including the one or more components, or the one or more wires, according to the replacement by said placing unit, or the re-routing by said routing unit.

21. An interactive circuit designing apparatus according to claim 19, wherein

said layout design unit further includes a grouping unit for grouping a plurality of block terminals and registering the plural terminals as a terminal group according to an instruction through said input unit for each layout hierarchy block, and

said placing region setting unit is operable to set the placing region for each group registered by said grouping unit according to an instruction through said input unit.

20. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design ofthe object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein said layout design unit is operable to divide the predetermined area into a plurality of layout hierarchy blocks in which the multiple components are to be disposed in a predetermined distribution and further includes a placing region setting unit for setting a placing region, within which a block terminal is to be placed, on a boundary of each layout hierarchy block according to an instruction through said input unit, where the block terminal is a logical component which is to be placed in one layout hierarchy block and connected to a logical component which is to be placed in another layout hierarchy block adjacent to the one layout hierarchy block, and

wherein said routing unit is operable to carry out the routing with placing the block terminal inside the placing region set for each layout hierarchy block by said placing region setting unit.

22. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design ofthe object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein said layout design unit is operable to divide the predetermined area into a plurality of layout hierarchy blocks in which the multiple components are to be disposed in a predetermined distribution and further includes a forbidden region setting unit for setting a forbidden region, within which a block terminal is not to be placed, on a boundary of each layout hierarchy block according to an instruction through said input unit, where the block terminal is a logical component which is to be placed in one layout hierarch block and connected to a logical component which is to be placed in another layout hierarchy block adjacent to the one layout hierarchy block, and

wherein said routing unit is operable to carry out the routing with placing the block terminal outside the forbidden region set for each layout hierarchy bock by said forbidden region setting unit.

23. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components, said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the obiect circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routing the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein said layout design unit further includes a placeable position determining unit responsive to an instruction through said input unit, said placeable position determining unit being operable, when the multiple components of the object circuit include both an input/output circuit, which is to be placed in a predetermined position on a substrate, and one or more input/output terminals, which are to be placed on a surface of the substrate and to be interconnected with one or more pins of the input/output circuit, to determine a placeable position, in which the one or more input/output terminals are to be placed, based on the predetermined position in which the input/output circuit is to be placed in such a manner as to diminish distances between the one or more input/output terminals and a respective one of the one or more pins of the input/output circuit, and

wherein said routing unit is operable to carry out the routing of a wire between the each of the one or more input/output terminals and the respective one of the one or more pin of the input/output circuit based on the placeable position of the one or more input/output terminals determined by said placeable position determining unit.

24. An interactive circuit designing apparatus for designing an integrated circuit which includes a multiplicity of logic components placed in a predetermined area on a substrate, each component having at least one pin, and a multiplicity of wires routed in the predetermined area on the substrate, each wire interconnecting at least two pins of the multiple components, in an interactive manner based on a logic design of the object integrated circuit to be designed, which logic design defines both the required multiple components of the object circuit and the interconnection relationship between the multiple components said apparatus comprising:

(I) a layout design unit for carrying out layout designing of the object circuit based on the logic design of the object circuit, said layout design unit including;

(i) a placing unit for placing the multiple components in the predetermined area on the substrate based on the logic design of the object circuit, and

(ii) a routing unit for routine the multiple wires to interconnect pins of the multiple components placed by said placing unit based on the logic design of the object circuit;

(II) a display unit for displaying various data concerning the layout designing by said layout design unit, which data includes both a result of placement by said placing unit and a result of routing by said routing unit;

(III) a display control unit, responsive to said layout design unit, for controlling said display unit such that said display unit displays data appropriate to a current stage of the layout designing by said layout design unit; and

(IV) an input unit for inputting to said layout design unit various items of information necessary for circuit designing in response to the current data displayed by said display unit, thereby allowing circuit designing to be carried out in an interactive manner,

said layout design unit being cooperatively connected with both said display control unit and said input unit in a manner so as to facilitate both the inputting operation of said input unit and the display controlling operation of said display control unit, thereby causing improved efficiency of interactive operations in circuit designing,

wherein said layout design unit further includes a limited region setting unit responsive to an instruction through said input unit, said limited region setting unit being operable, when the multiple components of the object circuit include an input/output circuit and one or more input/output terminals, which are to be placed in predetermined positions on a surface of the substrate and to be interconnected with one or more pins of the input/output circuit, to set a limited region, within which the input/output circuit is to be placed, based on the predetermined positions in which the one or more input/output terminals are to be placed in such a manner that each of distances between the one or more input/output terminals and a respective one of the one or more pins of the input/output circuit is below a predetermined value, and

wherein said placing unit is operable to place the input/output circuit inside the limited region set by said limited region setting unit.