JPH0239328A - Literal address allocating device - Google Patents

Abstract

PURPOSE:To improve the literal retrieving efficiency and then the compiling efficiency by registering a literal pool table after dividing it into pieces according to the literal length. CONSTITUTION:A literal retrieving means 3 retrieves successively a literal pool minor table 52 in the case the literal length inputted via a literal input means 2 is less than (n) bytes. While the means 3 retrieves a literal pool major table 53 based on the address stored in a literal control table 51 and uses the coincident address as a literal allocation address in the case the literal length is more than (n) bytes. The new literals are successively registered into the table 52 by a literal register means 4 in the case the literal length is less than (n) bytes. While these literals are registered into the table 53 in the case the literal length is more than (n) bytes. Then the address registered in the table 51 and the literal length are registered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applied to a compiler that can write literals in the procedure division of a source program. In particular, it relates to literal optimization means.

〔overview〕

The present invention improves compilation performance by searching a table that stores literals that are likely to match and determining addresses for allocation in a literal optimization means written in the procedure division of a text file of a compiler. It is designed so that it can be easily understood.

[Conventional technology]

The conventional method for optimizing literals in the Procedure Division is to register literals in the literal pool table in the order of their appearance without considering the length of the literal, and to search the literal pool table sequentially to find out whether the same literal exists. Ta.

[Problem that the invention seeks to solve]

n bytes (n means that when comparing literals, the longer a literal is, the less likely it is to match another literal; (means the maximum length of a literal with a high value).
Numerical literals such as ``0'' or ``1'' or numbers from ``1'' to rloo J are often used repeatedly.

Furthermore, as literals of n or more bytes, character literals are often used that are output on a screen terminal device or on a ledger and are visually checked by a person.

By the way, in the conventional example, literals are registered in the literal pool table in the order in which they appear, and the literal pool table is sequentially searched to see if the same literal exists, so when searching for a numeric literal of less than n bytes, In some cases, you are searching for a character literal of n or more bytes that has a low possibility of matching, and when searching for a character literal of n or more bytes, you are searching for n
This has the disadvantage that compile performance deteriorates because the part of the numerical literal that is less than a byte may be searched.

The present invention aims to eliminate such drawbacks and to provide a literal address allocation device that does not cause deterioration in compilation performance.

[Means for solving problems]

The present invention provides a literal address allocation device connected to a text file in which literals are described in the procedure division, including a storage means for storing a management table, a first table, and a second table, and a literal address assignment device connected to a text file in which literals are written in the procedure division. If a matching literal is not stored in the first or second table above, and the length of the input literal is less than the specified length, this literal is registered in one area of the first table above, and the input If the length of the literal is greater than or equal to the predetermined length, register this literal in one area of the second table, and pair the length of this literal with the address of the area where the literal is registered in this second table. a registration means for registering in the above management table using the above text file; If the length of the input literal is greater than or equal to the predetermined length, the second table is searched based on the address paired with this literal registered in the management table. The present invention is characterized by comprising a search means for determining the address of the searched area as the address for assigning the literal.

[Effect]

When a literal written in the Procedure Division is input and the length of this literal is less than n bytes, the literal pool small table is sequentially searched to see if the same literal exists, and n
If it is more than a byte, the large literal pool table is searched from the address registered in the literal management table to see if the same literal exists, and if there is a match, the matching address is assigned to that literal. do.

In addition, if the same literal does not exist in the literal pool small table or the literal pool large table, and the length of the literal is less than n bytes, that literal is registered in the literal pool small table, and the literal length is n bytes.
If the length is more than bytes, the literal is registered in the literal Boolean large table, and the registered address is assigned as the address, and if the literal length is n bytes or more, the registered address and the literal length are assigned. Register in the literal management table.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block configuration diagram showing the configuration of this embodiment.
FIG. 2 is a flowchart showing the operation of the literal search means, FIG. 3 is a configuration diagram showing an example of the configuration of a literal pool small table, and FIG. 4 is a configuration diagram showing an example of the configuration of a literal management table and a literal pool large table. It is.

As shown in FIG. 1, this embodiment is composed of an intermediate text file 1, a literal input means 2, a literal search means 3, a literal registration means 4, and a main storage device 5. Here, the main storage device 5 includes: As shown in Figures 3 and 4,
When compiling, there is a literal management table 51 in which the length of an address literal pointing to a literal in the large literal pool table 53 is registered, a small literal pool table 52 in which literals of less than n bytes are registered, and a literal of n or more bytes is registered. It also includes a large literal pool table 53 to be registered. That is, this embodiment is connected to an intermediate text file 1 which is a text file in which literals are described in the procedure division, and has a literal management table 51 which is a management table, a literal pool small table 52 which is a first table, and a second table. The main storage device 5 is a storage means for storing a large literal pool table 53, and when a literal that matches the literal input from the text file is not stored in the first or second table, the input literal If the length of is less than the predetermined length, register this literal in one area of the first table above, and if the length of the input literal is greater than the predetermined length, register this literal in one of the areas of the second table above. A literal registration means 4 registers the address of the area in which the literal is registered in the second table and the length of this literal as a pair and registers it in the management table, and inputs from the text file. When a literal matching the entered literal is stored in the first or second table, if the length of the input literal is less than the predetermined length, search the first table;
Additionally, if the length of the input literal is longer than the predetermined length, the second table is searched based on the address paired with this literal registered in the management table, and the address of the searched area is set to the address of this literal. The layout is provided with a literal search means 3 which is a search means defined in the address.

Next, the operation of this embodiment will be explained. The literal input means 2 inputs literals written in the procedure division from the intermediate text file 1. If the length of the input literal is less than n bytes, the literal search means 3 sequentially searches the literal pool small table 52 to see if the same literal exists, and if there is a match, the matching address is searched for the literal. is assigned to an address. If the length is n bytes or more, the large literal pool table 53 is searched from the addresses registered in the literal management table 51 in the order shown in the flowchart of FIG. 2 to see if the same literal exists. makes the matching address the literal assignment to address.

That is, first, the index is set to the first position of the literal management table 51 (step 31).

The length of the literal to be searched is compared with the value of the literal length field of the literal management table 51 pointed to by the index (step S2), and if the length of the literal to be searched is long, the index is added.Step S3
), if the index is in the literal management table 51, the search process continues (step S4). The literal to be searched is compared with the literal in the literal Boolean large table 53 pointed to by the address field of the literal management table 51 (step S5), and if they match, the address of the matched literal in the literal pool large table 53 is assigned to the literal. is an address (step S6).

The literal registration means 4 is a literal pool small table 52.
Alternatively, if the same literal does not exist in the large literal pool table 53 and the length of the literal is less than n bytes, the literals are registered in the free space of the small literal pool table 52 in sequence, and the registered addresses are assigned to the literal. The assignment is as an address, and when the length of the literal is n bytes or more, the literal is registered in the free area of the literal pool large table 53 in order, and the registered address is assigned as an address, and the registered address and literal are assigned as addresses. and the length of are registered in the literal management table 51 as a pair.

〔Effect of the invention〕

As explained above, the present invention creates a literal pool table in which literals of less than n bytes are registered and a literal boolean table in which literals of n bytes or more are registered, and searches for literals of less than n bytes are performed by n bytes. Literal Boolean tables in which literals less than or equal to the number of literals are registered are sequentially searched, and to search for literals of n or more bytes, the literal pool table in which literals of n or more bytes are registered is searched for each registered literal. Since only the length of is compared at once, search efficiency is improved and compilation performance can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a flowchart showing the operation of the literal search means. FIG. 3 is a configuration diagram showing an example of a literal pool small table. FIG. 4 is a configuration diagram showing the correlation between the literal management table and the literal pool large table. DESCRIPTION OF SYMBOLS 1... Intermediate text file, 2... Literal input means, 3... Literal search means, 4... Literal registration means, 5... Main storage device, 51... Literal management table, 52. ...Literal pool small table, 53
...literal pool large table.

Claims (1)

[Claims] 1. In a literal address allocation device connected to a text file in which literals are described in the procedure division, a management table (51), a first table (52), and a second table (53) are stored. and a storage means (5) for storing the literal input from the above text file if the length of the input literal is less than a predetermined length when a literal that matches the literal input from the text file is not stored in the first or second table. is registered in one area of the first table above, and if the length of the input literal is greater than the predetermined length above, this literal is registered in one area of the second table above, and the literal is registered in the second table. a registration means (4) for registering a pair of the address of the area where is registered and the length of this literal in the management table; and a literal that matches the literal input from the text file in the first or second table. When stored, if the length of the input literal is less than the predetermined length, the first table is searched, and if the length of the input literal is greater than or equal to the predetermined length, it is registered in the management table. A search means (3
) A literal address allocation device characterized by comprising: