JP2957025B2 - Functional level simulation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for designing a logic circuit.
The present invention relates to a function level simulation apparatus used for describing the operation of a logic circuit in a function description language and performing design verification by performing a simulation using the function description language.

[0002]

2. Description of the Related Art A functional level simulation is described in, for example, Iwanami Koza Microelectronics Vo.
l. 4 "VLSI Design II". In recent years, with the increase in the scale of LSIs, it has been said that it is important to perform sufficient design verification at an early stage of design, and functional level simulation is often performed as verification means.

FIG. 6 is a block diagram of a conventional function level simulation apparatus. In FIG. 6, reference numeral 31 denotes a language analysis unit which reads a function description language and analyzes its contents. If there is a grammatical error in the function description language, the language analyzing unit 31 reports the type of the error to the user,
If there is no error in the function description language, the analysis result is output. Normally, this analysis result has a data structure called a syntax tree, which is the same as the description contents. Numeral 32 is a simulation information generating means which receives the analysis result of the language analyzing means 31 and extracts information necessary for the simulation. Specifically, it outputs a program that secures a storage area corresponding to the variables used in the description language or calls an execution function that simulates the operation of the description sentence. Numeral 33 denotes a simulation executing means, which actually executes a function level simulation based on the simulation information received from the simulation information generating means 32.

[0004] A functional level simulation is performed,
When the user looks at the results, he sees the values of the variables used in the functional description. If two or more descriptive statements are executed at the same time and different values are assigned to the same variable, a collision occurs there. In such a function level simulation apparatus, in such a case, the value of the variable is set to “undefined value”. When the value of the variable becomes "indeterminate", the user knows that a collision has occurred.

[0005] Collision caused by simultaneous movement of a plurality of description sentences is a phenomenon peculiar to a function description language. This is because the function description language has the ability to express the parallel operation of the hardware, and is essentially unavoidable. The purpose of functional level simulation is to check whether the functional description written by the user really represents the intended operation of the user. In most cases, as described above, a collision does not occur as intended by the user. In the case of a collision, the user searches for the cause of the collision and describes it so that the collision does not occur. Will be corrected.

[0006]

In such a conventional function level simulation apparatus, when the description becomes large and reaches several hundred lines, a plurality of description statements are simultaneously executed, a collision occurs, and the value of the variable is changed to "100". In the case of "indeterminate value", there is a problem that it is very difficult to find the cause of the collision. That is, a certain variable “a” becomes “undefined value” due to collision.
However, it is not known from the value of the variable a which assignment statement and which assignment statement were executed and collided.
Further, when the description becomes large, it is difficult to simply search all places where the assignment to the variable a may be performed. Even if it could be done, it took a lot of time to find out which ones were colliding with which ones.

The present invention has been made in view of the above problems, and provides a function level simulation apparatus which allows a user to easily search for a cause of a collision of assignment to a variable even when the scale of a function description becomes large. The purpose is to do so.

[0008]

In order to solve the above-mentioned problems, in the function level simulation apparatus of the present invention, a collision of assignment to a variable occurs when assignment to the same variable is performed at a plurality of points in the description. Focusing on the fact that each statement is written under different conditions, collecting assignment statements centering on the variable at the assignment destination and organizing it into a list makes it possible to search for the cause even if a collision occurs It is intended to be easy.

Specifically, the function level simulation apparatus of the present invention reads a function description language and analyzes it, and reorganizes and displays the description information from the language analysis means and the analysis result of the language analysis means. Analysis result display means, simulation information generation means for extracting simulation information necessary for function level simulation from the analysis result of the language analysis means, and simulation based on the simulation information sent from the simulation information generation means Simulation execution means, wherein the analysis result display means comprises:
For each variable used in the function description language, the assignment statement in which the above variable is assigned, its line number, and execution conditions are arranged and output as a list.

Further, the function level simulation apparatus of the present invention comprises a language analysis means for reading and analyzing a function description language, and simulation information for extracting simulation information necessary for a function level simulation from the analysis result of the language analysis means. Generating means, simulation executing means for executing a simulation based on the simulation information sent from the simulation information generating means, and displaying and rearranging the information of the description based on the analysis result of the language analyzing means; Analysis result / execution result display means for adding and displaying simulation result information of the means, wherein the analysis result / execution result display means assigns to the variables for each variable used in the function description language. Assignment statements performed and their The line conditions are arranged and output as a list. At the time of executing the simulation, the simulation result information is received from the simulation executing means, and when a collision of the assignment to the above variable occurs, the assignment statement which caused the collision is emphasized. It is intended to be displayed.

[0011]

According to the above arrangement, at the time of inputting the function description language, the assignment statement in which assignment is performed to the variable and the execution condition thereof are arranged for each assignment destination variable and output as a list. By looking at this list, the user can see the assignment statements and their execution conditions that may cause a collision for each variable, so they can notice simple mistakes before trying to run the simulation. Even if a collision actually occurs by executing a simulation, it is easy to find the cause.

Further, in a list in which the assignments to be assigned to the above variables are assigned to each of the variables at the time of the simulation and the execution conditions thereof are arranged, the assignments executed when a collision occurs are emphasized. Since the information is displayed, the user can easily know the cause of the collision.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a functional level simulation apparatus according to the present invention will be described using embodiments. FIG. 1 is a block diagram of a functional level simulation apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a language analysis unit which reads a function description language and analyzes its contents.
The language analysis unit 11 reports the type of the syntax error to the user when there is a syntax error in the function description language, and outputs an analysis result when there is no error in the function description language. Reference numeral 12 denotes simulation information generation means, and language analysis means 11
Receiving the analysis result of, and extracting information necessary for the simulation. The operations of the language analyzer 11 and the simulation information generator 12 are the same as those of the conventional language analyzer 31 and simulation information generator 32, respectively.
Numeral 13 denotes a simulation executing means, which actually executes a function level simulation based on the simulation information received from the simulation information generating means 12. Numeral 14 denotes an analysis result display means, which rearranges and displays the information of the description based on the analysis result of the language analysis means 11.

FIGS. 2 and 3 are views for explaining the contents of the display output by the analysis result display means 14. FIG. FIG. 2 is a diagram illustrating an example of a function description language. In FIG. 2, a, da
tal, data2, reg1, reg2, sel, etc. are all variables. In FIG. 2, a line number is added to the left end of the description sentence, and the description will be made with reference to the line number. The first to third lines indicate that when sig1 is a value of 1,
This is a conditional assignment statement that assigns the value of atal.
From line 5 to line 18, if is doubled,
The meaning is that when the condition of the outside if is satisfied and the condition of the inside if is also satisfied, the inside assignment statement is executed. Therefore, in the assignment statements on the seventh and eighth lines, the variable disable is 0 and the variable st
An assignment statement is executed when art is 1. Also, since the assignment statements on lines 10 and 11 are on the side of else, the variable s
When start is other than 1 (that is, 0) and the variable d
Substitution is performed when "isable" is 0.

FIG. 3 is a diagram showing an example of display output of the analysis result display means when the function description of FIG. 2 is input to the first embodiment of the present invention. The left-hand side of the original description, that is, the variable of the substitution destination, is enclosed in a frame and listed. The number written to the right outside the frame corresponds to the line number in the original description. From this list, it is possible to grasp all substitution operations for each variable.
For example, the substitution operation for the variable a is performed in line number 2, s
When the value of data is substituted when igl is 1, the variable disable is 0 and the variable s
When the value of data2 is substituted when el is 1, 2
It turns out that there is one. By looking at this list,
For example, for variable a, sigl = 1 and disab
If le = 0 and sel = 1 occur at the same time, it can be easily predicted that a collision will occur.

In the case of FIG. 3, only two assignment statements exist for each variable. However, in a more complicated description, there may be many assignment statements for one variable. This format, in which each variable is summarized in a table, is easy to see.

FIG. 4 is a block diagram of a functional level simulation apparatus according to a second embodiment of the present invention. In FIG. 4, reference numeral 21 denotes a language analyzing unit which reads a function description language and analyzes its contents. The language analysis unit 21 reports the type of the syntax error to the user when the function description language has a syntax error, and outputs an analysis result when the function description language has no error. Numeral 22 is a simulation information generating means for receiving the analysis result of the language analyzing means and extracting information necessary for the simulation. The operations of the language analyzer 21 and the simulation information generator 22 are the same as those of the conventional language analyzer 31 and simulation information generator 32, respectively. Reference numeral 23 denotes a simulation execution unit that actually executes a function level simulation based on the simulation information received from the simulation information generation unit 22. Numeral 24 denotes an analysis result / execution result display means for rearranging and displaying description information based on the analysis result of the language analysis means 21. Upon execution of the simulation, the simulation information result is received from the simulation execution means 23, and the assignment conflict occurs. Highlights the assignment statement that caused the conflict if.

FIG. 5 is a diagram showing an example of a display output of the analysis result / execution result display means 24, which is basically the same as FIG. When a signal collision occurs at the variable a during the execution of the simulation, the assignment statements corresponding to the line numbers 2 and 16 and the conditions thereof are highlighted in bold as shown in this figure. In the example of FIG. 5, there are only two assignment statements for each variable,
In a more complex description, there may be many assignment statements for one variable, in which case only two or three assignment statements that actually caused a collision are highlighted. In such a case, the present embodiment is particularly effective. The emphasis method is not limited to the bold type, but may be, for example, a method of changing colors.

[0019]

As described above, according to the present invention, the analysis result display means 14 for rearranging and outputting description information centering on variables is provided. By outputting the list of numbers and execution conditions, when a collision occurs in substitution to a variable during simulation execution, the user can easily find the cause. In addition, the user can look at the above list at the end of the description, so that it is easy to predict whether or not a collision may occur without actually performing a simulation. Writing errors when writing can be reduced. Therefore, the verification efficiency of the function description of the user can be improved.

Further, an analysis result / execution result display means 24 is provided, and when a collision of assignment to a variable occurs during simulation execution, the assignment statement for which assignment is being executed is highlighted in a list for each variable. By doing so, it is possible to know at a glance which assignment statement and which assignment statement are causing a collision, and correct the description language to avoid the collision. From this, an effect is obtained that the efficiency of verification of the user's function description can be further increased.

[Brief description of the drawings]

FIG. 1 is a block diagram of a functional level simulation device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a function description language in the function level simulation device according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of an analysis result display in the function level simulation apparatus according to the first embodiment of the present invention.

FIG. 4 is a block diagram of a functional level simulation device according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of a highlighted display of an analysis result in the function level simulation apparatus according to the second embodiment of the present invention.

FIG. 6 is a block diagram of a conventional function level simulation device.

[Explanation of symbols]

 11 Language analysis means 12 Simulation information generation means 13 Simulation execution means 14 Analysis result display means 21 Language analysis means 22 Simulation information generation means 23 Simulation execution means 24 Analysis result / execution result display means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G06F 11/28 G06F 11/28 E

Claims (2)

(57) [Claims] 1. A language analysis means for reading and analyzing a function description language, an analysis result display means for rearranging and displaying description information based on an analysis result of the language analysis means, and an analysis of the language analysis means. Simulation information generation means for extracting simulation information necessary for the function level simulation from the result; and simulation execution means for executing a simulation based on the simulation information sent from the simulation information generation means, and displaying the analysis result. The function level is characterized in that, for each variable used in the function description language, an assignment statement to be assigned to the variable, its line number and execution conditions are arranged and output as a list. Simulation device. 2. A language analysis means for reading and analyzing a function description language, a simulation information generation means for extracting simulation information necessary for a function level simulation from an analysis result of the language analysis means, and a simulation information generation means Simulation execution means for executing a simulation based on the simulation information sent from the apparatus; and displaying and rearranging the information of the description based on the analysis result of the language analysis means, and additionally displaying the simulation result information of the simulation execution means. The analysis result / execution result display means includes, for each variable used in the function description language, an assignment statement to be assigned to the variable and an execution condition thereof. Organize and output as a list, A function level simulation apparatus, which receives simulation result information from a simulation execution unit when a simulation is executed, and highlights an assignment statement that caused the collision when the collision of substitution into the variable occurs.