JPS63153851A - Lsi lay out process - Google Patents

Abstract

PURPOSE:To digitize the coupling degree of blocks enabling them to be arranged by computation for automation by a method wherein the blocks are replaced with dynamic model using the size of blocks, the number wirings between blocks and allowable delay in wiring as parameters. CONSTITUTION:Respective functional blocks 5-8 represented by circles corresponding to respective capacities are provided with repulsion corresponding to the circles. The wirings between respective blocks are substituted for springs connecting the blocks while the length of wirings is equivalent to the sum of radiuses of blocks connected while the spring constant is to be the sum of products of connection numbers and weight of allowable delay. Assuming the distance between blocks as x, the force F1=-kx is given to respective blocks 5-8 in this model while the repulsion between blocks is equivalent to F2=l/r<2> (l represents coefficient of repulsion). Respective blocks are shifted in the direction of forces given until said forces are balanced. Through these procedures, respective blocks can be replaced with the actual functional blocks by specified arrangement to finish the arrangement of respective blocks 1-4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for arranging a plurality of functional blocks arranged inside an LSI, and particularly to an LSI layout method for optimally arranging each functional block.

[Prior Art] Conventionally, in this type of LSI layout method, the designer instructs the layout based on information on the degree of coupling between functional blocks at the time of design, or the amount of wiring between each functional block and the allowable delay time per function. The size of the blocks was investigated and the layout was done manually based on that information.

[Problems to be Solved by the Invention] The above-described conventional LSI layout method has the drawback that each functional block is arranged manually, and therefore cannot be automated, resulting in an increase in manufacturing time.

Furthermore, there is also the drawback that there are individual differences in the skill level of the person doing the layout.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an S2 layout method.

[Means for Solving the Problems] The present invention provides a method for arranging functional blocks, which are a collection of circuits that perform specific operations, arranged inside an LSI. This is an LSI layout method characterized by modeling parameters such as allowable delay time into dynamic forces and determining the optimal layout based on the strength of the forces.

[Example] Next, embodiments of the present invention will be described using the drawings.

FIG. 2 is an example showing the functional blocks to be arranged by the method of the present invention and the interconnections between them.

In this example, functional blocks 1, 2, 3, and 4 are placed. There are 5 wires between functional blocks 1 and 2, 3 wires between 2 and 3, 2 wires between 1.3, and 2 wires between 3° and 4, respectively. shall be taken as a thing. Further, it is assumed that each of the wirings 13, 14, 15, and 16 does not include any wiring that has particularly severe delay times.

FIG. 1 shows the relationship between the functional blocks shown in FIG. 2 using a mechanical model. Each functional block 5 to 8 is represented by a circle corresponding to the size.
There is a repulsive force between them that corresponds to the circle. The wiring between each block has been replaced with a spring that connects the blocks.
Its length is equal to the sum of the radii of connected blocks, and its spring constant is the sum of the number of connections multiplied by the delay tolerance weight. In Figure 2, 5.6.7.8 represents a model of functional blocks 1 and 2.3.4, and the wiring between each block is a spring 9°io, 11.12
It is represented by

Here, each spring 9 to 12 has the same delay weight, so spring 9 has a weight of 5, spring 10 has a weight of 3, and spring 11 has a weight of 2k.

It can be assumed that spring 12 has a spring constant of 2. Further, each block 5 to 8 is set to have a repulsive force proportional to the sum of their radii. This is to prevent other blocks from clumping together in a block where many wirings are concentrated and running out of wiring area during wiring. each block 5
~8, if the distance between blocks is X, then F1=-k
This model receives the force x, and the repulsive force between the blocks is F2=] (l is the repulsive force coefficient).

Move each block in the direction of the forces it receives until the point where these forces are balanced, and when you move to the point where the blocks are balanced, the third
It becomes a diagram. By replacing this arrangement with the actual functional blocks according to the arrangement required by this FIG. 3, the arrangement of each block 1 to 4 shown in FIG. 4 is completed. In other words, the layout method of the present invention models the strength of the coupling between each functional block as an attractive force weighted by the amount of wiring between them and the delay time allowed for that wiring, and also By expressing it as a circle with a radius corresponding to the size of the circle, and creating a repulsive force between the functional blocks that corresponds to the size of the circle, the equilibrium point of the force is determined by measuring, and the optimal arrangement is automatically determined. .

If there is a wiring between blocks that has a severe delay time, this can be dealt with by increasing the spring constant of the model corresponding to that wiring.

[Effects of the Invention] As explained above, the present invention can determine the functional blocks to be placed in the SI depending on the size of the blocks, the number of wires between the blocks,
By replacing the wiring delay tolerance with a mechanical model as a parameter and arranging the blocks by balancing the forces between them, it is possible to quantify the degree of coupling between blocks, which was previously difficult to quantify. Since placement can be done by calculation, it becomes possible to automate what was previously placed manually.

In addition, it has the effect that items can be placed with a constant quality, whereas the placement efficiency was determined by the skill level of the worker.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a model modeled in an embodiment of the present invention, Fig. 2 is a diagram showing the wiring relationship of modeled actual functional blocks, and Fig. 3 is a diagram showing the model in an equilibrium state. The figure shown in FIG. 4 is a diagram showing the arrangement of actual functional blocks.

Claims (1)

[Claims] (1) In the method of arranging functional blocks, which are a collection of circuits that perform specific operations, arranged inside an LSI, parameters such as the size of each functional block, the amount of wiring between functional blocks, and the allowable delay time are dynamically determined. An LSI layout method characterized by modeling a force and determining the optimal layout based on the strength of the force.