JP2621898B2 - Dynamic resolution processing method of external reference type address constant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a method for dynamically resolving an external reference type address constant in a data processing system having a processing function of dynamically combining independently created programs at the time of execution. An unresolved reference that resolves at least the unresolved branch-type address constant and that refers to the address of an external program, so that it can refer only to the address of another program that is not statically bound. An execution management unit having a processing means for loading an external program when there is a type address constant and resolving the reference type address constant, and a branch type and reference type address constant to be dynamically resolved, Control is passed to each entry at the time of branching to another external program, and an instruction for transferring control to the execution management unit and an external program. And a link control table having program information. When a dynamic connection request of each program is requested, the execution management unit is started via the link control table, and a reference type address constant of an external program related to the program to be connected is stored. Configure to resolve.

[Industrial applications]

The present invention relates to a method for dynamically resolving an external reference type address constant in a data processing system having a processing function of dynamically combining and operating independently created programs at the time of execution.

[Conventional technology and its problems]

When combining independently created programs, a so-called linker (linkage editor)
A method in which one load module is statically combined in advance and a dynamic link method in which each program is prepared as a separate load module and dynamically combined at the time of execution are used.

With the dynamic link method, each program must be created independently, and if any of the programs is changed or modified, it is necessary to redo the static link processing without affecting other programs. There is a merit that there is no.

However, according to the conventional dynamic link method, when one program calls another program, that is, when control is transferred to another program by branching, dynamic link can be used. If only the address of another program is referred to, dynamic linking cannot be used. Therefore, in such a case, the modules must be linked by static linking in advance. Did not.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide means for making it possible to refer only to the address of another program that is not statically linked by execution-time linking.

[Means for solving the problem]

 FIG. 1 is a diagram illustrating the principle of the present invention.

In FIG. 1, 10 is an execution management unit, 11 is a branch type address constant resolution processing unit, 12 is a reference type address constant resolution processing unit, 13
Is a link control table, 14 is an operating system (OS), 15 is a loader for loading a program into a memory, 16 is a load module on an external storage device, 20A to 20C are programs that are individual load units, 21A Or 21C is a dynamic link table (DALTA
B).

In the present invention, the execution management unit 10 is provided for resolving a branch type address constant and a reference type address constant between programs created as individual load modules. Execution management 10 is a branch-type address constant resolution processing unit.
11 and a reference-type address constant resolution processor 12.
The branch-type address constant resolution processing unit 11 performs a process of loading and combining a program to be branched to by an unresolved branch-type address constant. If there is an unresolved reference type address constant that refers to the address of the external program in the loaded program, the reference type address constant resolution processing unit 12 performs processing for loading the external program and resolving the reference type address constant. Do.

The link control table 13 is a control table used by the execution management unit 10 for dynamic linking of programs.
Each entry corresponds to a branch type and reference type address constant to be dynamically resolved. Control is passed to each entry of the link control table 13 when branching to another program by a branch address constant.
It has an instruction sequence for transferring control to the execution management unit 10, and has external program information related to a branch type or reference type address constant.

For example, when branching from the program 20A to another program 20B, in the prior art, the loader 15 of the operating system 14 is called from the linkage entry in the DALTAB 21A, and a dynamic link is executed to branch.

On the other hand, in the present invention, the execution management unit 10 is called via the link control table 13. The execution management unit 10 uses the branch-type address constant resolution processing unit 11 to dynamically link the program 20B as before, and the reference-type address constant resolution processing unit 12 allows the program 20B to refer to the inside of another program 20C. When doing so, the reference type address constant is solved by loading the program 20C in advance.

[Action]

The operation of the present invention will be described below with reference to FIG.

The execution management unit 10 loads the link control table 13 first.

For example, when the execution of the program 20A proceeds and an instruction for branching to another program 20B is executed, control is transferred to the head of the corresponding entry in the link control table 13 by branching to the address of the V-format address constant.

In the entry, an instruction sequence for shifting to the execution management unit 10 is embedded in advance, and the execution management unit 10 obtains execution control.

The execution management unit 10 includes a branch-type address constant resolution processing unit 11
As a result, a load request for the program 20B is issued to the loader 15.

This allows the load module on the external storage device
The program 20B is loaded from 16.

Next, the reference-type address constant resolution processing unit 12 is activated.

Then, the DALTAB 21B of the program 20B is referred to check whether or not there is a reference type address constant that refers to the external program.

If there is a reference-type address constant that refers to an external program, the link control table 13 is searched to find an entry corresponding to the reference-type address constant.

A load request for the program 20C is issued to the loader 15, and the program 20C is loaded. After loading the program 20C, the address is set to the reference type address constant indicating the program 20C.

When the processing for all the reference type address constants is completed, the processing branches to the program 20B.

With the above processing, when the dynamic link is performed by the branch type address constant, the reference type address constant for the external program referred to by the dynamically linked program is also resolved at that time.

〔Example〕

FIG. 2 is an example of an entry configuration of DALTAB used in one embodiment of the present invention, FIG. 3 is an example of an entry configuration of a link control table according to one embodiment of the present invention, and FIG. FIG. 5 shows an example of the process of the execution management unit, FIG.
The figure shows an embodiment of the present invention.

The linker (linkage editor) uses the DALTAB with the entry configuration shown in Fig. 2 from the external program information output by the compiler at the beginning of the object program.
21 and a link control table 13 having an entry configuration as shown in FIG.

DALTAB21 is in each program and has external program information in that program. The flag section 21a in each entry has a flag for identifying whether the entry is related to a branch address constant or a reference address constant. In the case of the reference type, the next address / displacement unit 21b has a pointer to an address constant indicating the external program (displacement from the beginning of the program). In the case of the branch type, the address has an address to an entry of the link control table 13 for performing the address resolution. The external program name part 21c has external program name information specified by a branch type or reference type address constant.

There is one link control table 13 for each program library, and has all the member information in the program library. When the program is executed, the link control table 13 is loaded first. One entry format is like 13a to 13h shown in FIG.

Field in link control table 13 entry
13a has an instruction sequence for shifting the execution control to the execution management unit 10. The field 13b has the address of the execution management unit 10. Fields 13c, 13d, and 13e are save areas for general-purpose registers R15, R0, and R1, respectively. This save area is used by the instructions in the field 13a for saving registers.

Field 13f has a pointer to DALTAB in this program. This pointer is a displacement from the beginning of this program. Field 13g is an area where an address is entered when this program is loaded, and field 13h is an area having external program name information.

The instruction sequence stored in the field 13a is, for example, an instruction as shown in FIG.

The instruction of (i) stores the registers R15, R0, and R1 in the field 1
Instructions to be stored in 3c to 13e. When this instruction is executed, R15 contains the start address of this entry.

The instruction (ii) is an instruction for putting the contents of the register R15 into the register R1.

The instruction (iii) is an instruction for putting the address of the execution management unit 10 into the register R15.

Control is transferred to the execution management unit 10 by the instruction (iv).

The execution management unit 10 is provided with an instruction sequence as shown in FIG. 5 for dynamic linking using a branch address constant. Hereinafter, description will be given according to (i) to (viii) shown in FIG.

(I) The branch destination address is obtained from the field 13g in the entry of the link control table 13.

(Ii) Check whether the address of the branch destination is 0.

(Iii) If the address of the branch destination is not 0, since the data has already been loaded, the processing proceeds to the instruction (v).

(Iv) Request the operating system to load the branch destination program.

(V) Set the branch destination address in registers R0 to R15.

(Vi) Restore the register R0 from the field 13d.

(Vii) Restore register R1 from field 13e.

(Viii) Branch to a branch destination that is a dynamic link target.

Next, a specific example of the present invention will be described with reference to FIG. In FIG. 6, program 20A is equivalent to program 20B.
Control is passed to the program 20B.
It is assumed that another program (C) is referred to.

When the linker (not shown) changes the object module to a load module that is an executable expression,
As shown in Fig. (A), DALTAB21A, D
Create ALTAB21B. Further, a link control table 13 is created.

The link control table 13 indicates the locations of DALTAB21A and DALTAB21B in each program as shown in FIG. 6A by a relative address from the beginning of the program. Each DALTAB indicates the location of the address constant corresponding to each entry by a relative address from the beginning of the program, as shown in (1) and (2).

 At runtime, it works as follows.

First, it is started by the execution management unit 10 from the operating system. The execution management unit 10 loads the link control table 13, and stores the third
The address of the control transfer destination to the execution management unit 10 is stored in the field 13b shown in FIG. If the program is reentrant, an area for the link control table 13 is secured, and the contents of the link control table 13 are copied and used there.

Assuming that the program 20A is the main program, the program 20A is loaded, and its address (here, address 500) is set in the field of the corresponding entry in the link control table 13 as shown in FIG.
Set to 13g. And field 13g and field
From 13f, the start address of DALTAB21A in the program 20A is obtained. Since the start address of the program 20A is 500 and the displacement of the DALTAB21A is 100, it can be seen that the start address of the DALTAB21A is 600.

Next, a process of resolving the reference type address constant in the DALTAB 21A is performed. However, since there is no reference type address constant in the program 20A, the process is not performed here.

The address of the entry in the link control table 13 corresponding to the branch type address constant (B in this case) in the DALTAB 21A is obtained, and the value (address) is set in the V-type address constant in the program. The location of the V-type address constant is DALTA
It can be seen from the pointer (b) of B21A. The V-type address constant points to the corresponding entry of the program 20B, as indicated by a pointer (c) shown in FIG.

When all address constants have been resolved, control is passed to the program 20A.

When the execution of the program 20A proceeds and the instructions i1 and i2 shown in FIG. 6 (a) are executed, a process for shifting the control to another program (program 20B) is performed. Note that when transferring control to another program, the same applies to the case of static combination, but an instruction i1 and an instruction i2 are required.

The instruction i1 stores the branch destination (in this case,
The address of the entry of the link control table 13 corresponding to B) is entered, and control is transferred to the head of this entry by the next instruction i2 (BALR instruction). Then, control is transferred to the execution management unit 10 by executing the instruction shown in FIG.

The branch from the program 20A to the program 20B is performed in the execution management unit 10 by executing an instruction as shown in FIG.

In the program 20B, since the address of the external program C is referred to, the reference type address constant is resolved before branching to the program 20B. Therefore, first, DALTAB21B of the program 20B is searched.
If the address value is as shown in FIG. 6 (c), the DALTAB21B address is found from the link control table 13 to be 1000, the start address of the program 20B is 1000, and the DALTAB21B displacement is 200. Because we know that there is, we know that it is 1200 address.

Next, when the DALTAB 21B is searched, it is found that the program C is referred to by the reference-type address constant. Therefore, the link control table 13 is searched for an entry corresponding to the program C. Then, the loading of the program C is requested to the operating system, and the program C is loaded.
To load. Thereafter, the address of the program C is set in the corresponding entry of the link control table 13, and
The address is put in the reference type address constant in the program 20B. As described above, the reference type address constant for the program C which is an external program is resolved.

Also, the branch address constant in DALTAB21B (in this case,
The address of the entry in the link control table 13 for D) is obtained, and the V-type address constant (the sixth
The address of the entry is set in the pointer (d) indicated by (d) shown in FIG. This pointer is indicated by (e) in FIG.

When the above processing is completed for all address constants, control is passed to the program 20B.

〔The invention's effect〕

As described above, according to the present invention, at the time of dynamic connection by the branch type address constant, the reference type address constant referring to another program is also resolved there. Can also refer to the address of another program. Therefore, the independence of each program is increased, and the development and change of the program are facilitated.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is an example of an entry configuration of DALTAB used in one embodiment of the present invention, FIG. 3 is an example of an entry configuration of a link control table according to one embodiment of the present invention, FIG. 4 is an example of a sequence of instructions for shifting to the execution management unit, FIG. 5 is an example of processing of the execution management unit, and FIG. In the figure, 10 is an execution management unit, 11 is a branch type address constant resolution processing unit, 12 is a reference type address constant resolution processing unit, 13 is a link control table, 14 is an operating system, 15 is a loader, 16 is a load module, 20A-20C is a program, 21A-
21C represents DALTAB.

Claims (1)

(57) [Claims] In a data processing system having a processing function of dynamically combining programs created independently at the time of execution, at least a program to be branched to by an unresolved branch address constant is determined. Processing means for loading and combining; and processing means for loading an external program when there is an unresolved reference type address constant referring to the address of the external program in the loaded program and resolving the reference type address constant. In response to the execution management unit (10) and the branch-type and reference-type address constants to be dynamically resolved, control is passed to each entry when branching to another external program, and the execution management unit (10) A link control table (13) having instructions for transferring control and external program information is provided. An external reference type address constant, wherein the execution management unit is started via the link control table when a dynamic connection request is issued, and a reference type address constant for an external program relating to a program to be connected is resolved. Dynamic resolution processing method.