JP2585780B2 - DO loop optimization processing method for input / output library - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a data processing system provided with a FORTRAN compiler that analyzes input / output statements in a FORTRAN program and outputs an object program that calls a predetermined input / output library. The present invention relates to a DO loop optimization processing method in an input / output library that enables efficient input / output execution.

FORTRAN programs are often used for scientific and technical calculations, but the computer processing time is long depending on the amount of calculation and the amount of input / output data. Improvement is desired.

[Conventional technology]

 FIG. 6 shows an example of the prior art.

When a FORTRAN compiler inputs a source program such as the FORTRAN program 20, it performs syntax analysis and semantic analysis and creates an object program including machine language instructions and the like. If a source program contains an input / output statement such as a READ statement or a WRITE statement, an instruction that calls a program that performs the corresponding processing in a prepared input / output library is specified by specifying the variable to be input / output. Embed in the object program.

In the prior art, in the FORTRAN program 20, if there is a DO form of a multidimensional array and a READ statement specified as an input / output element, as shown in FIG. The I / O library was called from the object program one element at a time. That is, as shown in FIG. 6 (b), if the array to be input / output is three-dimensional, A (I, J, K) is obtained by nesting three loops of I, J, K. Input and output.

[Problems to be solved by the invention]

Therefore, there has been a problem that the number of calls to the input / output library increases and the processing time for creating parameters and saving / restoring registers increases.
In addition, there is a problem that a large number of determination processes of the number of loops in a multiplex loop are required.

The present invention solves the above problems and appears in input / output statements.
The purpose is to reduce the number of loop nests due to the DO form list and speed up input / output processing.

[Means for solving the problem]

 FIG. 1 shows a configuration example of the present invention.

In FIG. 1, 10 is a data processing device including a CPU and a memory, 11 is a FORTRAN compiler for translating a FORTRAN program described in FORTRAN language into a machine language level,
12 is an object program output as a translation result of FORTRAN compiler 11, 13 is an object program 1
2 is a linker that performs a combined edit of the FORTRAN library and the like and generates a load module as an executable form, 14 denotes a DO type and parameters, and 15 denotes an input / output library comprising a group of programs for input / output.

The FORTRAN compiler 11 determines at least the number of dimensions of the array, the length of the element, and the length of the element according to the DO form and the analysis result when an input / output statement in the input FORTRAN program (not shown) is detected. An DO program and parameters 14 having position information are created, and the DO program and parameters 14 are designated to output an object program 12 that calls an input / output library 15.

When the input / output library 15 is called from the load module of the object program 12 at the time of execution, the input / output library 15 analyzes the DO type and the parameters 14, and determines whether the number of arrays is one, the number of dimensions of the array is two or more, or not. The optimization conditions such as whether the increment address of each dimension is equal to the length of one element are checked, and if optimization is possible, the nest of DO loops in input / output list processing is reduced, and the It performs input and output.

[Action]

Conventionally, when there is a nest of DO loops in a normal executable statement in FORTRAN, optimization has been performed to reduce the nest by loop unrolling. However, in the input / output library 15 called from the object program 12, the object program 12
The nesting could not be reduced because the interface information from the server was not sufficient and the input / output library 15 was prepared in advance in a fixed manner.

In the present invention, a DO type and parameters 14 are prepared as interface information from the object program 12, thereby enabling the input / output library 15 to dynamically optimize the DO type list in the input / output statement. I have.

〔Example〕

FIG. 2 is an example of DO type arrangement parameters used in one embodiment of the present invention, FIG. 3 is an example of optimization according to one embodiment of the present invention,
FIG. 4 is an example of input / output processing according to an embodiment of the present invention, FIG.
The figure shows an example of the DO loop optimization processing according to one embodiment of the present invention.

If the FORTRAN program includes a DO form and an input / output statement to be specified, the FORTRAN compiler 11 shown in FIG. 1 outputs an object program 12 for creating DO form arrangement parameters 14 as shown in FIG. 2 as a translation result. I do.

As shown in FIG. 2, for example, as shown in FIG. 2, the parameter type, the number of array dimensions m, the number of arrays n, and the number of repetitions are set in the DO type list parameter 14, and the type of the list and the attributes of the list are set. , The length of one element, the address of the head element of the array element, the increment address value for each dimension, etc. are set for the number of arrays.

Normally, the DO type list parameter 14 is dynamically created by the object program 12, but may be statically provided in the data area if the value is determined.

For example, in the case of a READ statement of FORTRAN program 20 as shown in FIG.
The value set to 14 is as follows:

Parameter type = DO type list parameter Number of array dimensions (m) = 3 Number of arrays (n) = 1 Number of repetitions 1 = 3 Number of repetitions 2 = 5 Number of repetitions 3 = 5 Type of array = REAL * 4 Increased address value 1 = 8 Increased address value 2 = 4 Increased address value 3 = 4 Length of one element = 4 The conditions for DO loop optimization in processing input / output statements are as follows.

Number of arrays = 1 and number of array dimensions ≧ 2 and increasing address i =... = Increasing address i = 1 element length (where 1 ≦ i <j and successive integers from i to j) FIG. In the READ statement shown in parentheses), the array variables J and K
Satisfies this optimization condition and can be integrated into one dimension.
That is, the three-dimensional array of A (I, J, K) is
It can be handled like a two-dimensional array of (I, L), and the nest of loops is changed from triple to double.

FIG. 3 (b) shows the data area of the three-dimensional array of A (I, J, K), and FIG. 3 (c) shows the data area of the two-dimensional array of A (I, L). Is shown. READ shown in Fig. 3 (a)
The input / output elements based on the sentence are indicated by circles in FIGS. 3 (b) and 3 (c). However, even if the variables J and K are integrated into L, as shown in FIG. Are the same. The number of repetitions of L is obtained by multiplying the number of repetitions of J and K.

FIG. 4 (a) shows the same FORTRAN program 20 as in FIG. 3 (a).
The input / output processing in the input / output library 15 is performed as shown in FIG. That is, I, J, K
The double loop is reduced to a double loop by 1I, L, and the process of determining the number of repetitions is reduced. Therefore, the processing speed is increased. Since this processing is performed in the input / output library 15, the processing load on the object program 12 is reduced.

FIG. 5 shows the input / output library 15 shown in FIG.
9 shows an example of DO loop optimization processing. In the following description, 〜 corresponds to the process 示 す shown in FIG. Before starting the processing, the input / output library 15 determines whether or not the parameters are in the DO form list. If the parameters are not in the DO form list, the input / output processing is performed for each element as before. Also, it is determined whether or not array processing is possible. If array processing is possible, optimization processing by array processing is performed. Moves to the next DO loop optimization check if array processing is not possible.

First, it is determined whether the number of arrays is 1 to check whether DO loop optimization is possible. If the value is 2 or more, DO loop optimization cannot be performed, and input / output processing is performed as usual.

If the number of arrays is one, it is determined whether the number of dimensions of the array is two or more. If it is not more than 2, the nest cannot be reduced, so DO loop optimization cannot be performed.

If the number of dimensions of the array is two or more, next, a search is made for a dimension whose increasing address is equal to the length of one element in the input / output list, and a plurality of continuous dimensions are found.

If a plurality of continuous dimensions whose increment address is equal to the length of one element are not found, DO loop optimization cannot be performed.

When optimization is possible, a continuous dimension equal to the length of one element in the input / output list is defined as one dimension. If there is more than one continuous part, put them together. Then, the number of repetitions and the number of dimensions are newly obtained. The number of repetitions is obtained by multiplying the number of repetitions of each integrated dimension. For example, if there is the following six-dimensional array, the length of one element = 4 The one-dimensional increment address = 4 The two-dimensional increment address = 4 The three-dimensional increment address = 8 The four-dimensional increment address = 45 Increased address of dimension = 46 Increased address of 6 dimension = 4 One, two, and four, five, and six dimensions are targets of integration, respectively.

Input / output processing is performed for each element based on the input / output list information with the reduced number of dimensions.

〔The invention's effect〕

As described above, according to the present invention, when a DO form list having a plurality of dimensions appears in an input / output statement, the nest of DO loops in the input / output library is reduced under a predetermined condition. The performance of input / output processing by FORTRAN programs is improved.

[Brief description of the drawings]

FIG. 1 is a configuration example of the present invention, FIG. 2 is an example of DO type arrangement parameters used in an embodiment of the present invention, FIG. 3 is an example of optimization according to an embodiment of the present invention, and FIG. FIG. 5 shows an example of input / output processing according to an embodiment of the present invention, FIG. 5 shows an example of DO loop optimization processing according to an embodiment of the present invention, and FIG. In the figure, 10 is a data processing device, 11 is a FORTRAN compiler, 12 is an object program, 13 is a linker, 14 is a DO type arrangement parameter, and 15 is an input / output library.

Claims (1)

(57) [Claims] When the sequence of input / output elements specified in an input / output statement of a FORTRAN program is repeated in an array format, at least the number of dimensions of the array relating to the input / output elements and the input / output elements for each dimension Means for creating a parameter having repetition information; means for calling the input / output library for executing the input / output processing by designating the parameter; and analyzing the parameter specified by the caller in the called input / output library. If the number of dimensions of the array of input / output elements specified by the parameter is 2 or more, check the optimization conditions to see if multiple dimensions can be combined into one dimension, and By combining multiple dimensions into one dimension when satisfied, a loop for repeating input / output processing for each input / output element Reduce the door, DO loop optimization processing method in the input-output library comprising the means for performing the requested input and output processing.