JPH0344328B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] For example, when transferring control between a program module that operates in a virtual space addressed with 24 bits and a program module that operates with 31 bits, it is necessary to switch the address mode. There is a need to do. In the present invention, when the operation modes differ in dynamic link control, the program management section provides an extended migration entry to which control is passed from the dynamic link table, and by this extended migration entry, Extended branch instructions that involve address mode switching should be issued, especially for existing
This allows for address extension migration without any modification to modules operating in 24-bit mode.

[Industrial application field]

The present invention relates to a switching control method for address modes with different upper limits of virtual space, and in particular, an address mode switching control method using dynamic linking that enables smooth "address expansion migration" for existing programs with a dynamic link structure. It is related to.

[Conventional technology and problems]

In particular, in large computer systems, the scale of programs tends to grow larger year by year; for example, with a 24-bit address, the user program can be 16MB.
Since only 2GB of virtual space can be used, an address extension function is provided that uses 31 bits to address, allowing user programs to use a huge virtual space of up to 2GB. However, conventionally,
The program that was running in a 16MB virtual space was
It is not possible to use 2GB of virtual space as is; in order to reference addresses larger than 16MB, it is necessary to switch the address mode within the program. In other words, the so-called BX command
It is necessary to specify the address mode on the program status word (PSW) by using an extended branch instruction such as a BASX instruction that branches with address switching.

Therefore, in order for an existing user program to use 2GB of virtual space, processing for switching the address mode within the program must first be added to the program. However, there are generally hundreds or thousands of existing modules, and there is a problem in that it is extremely difficult to modify them all at once.

Therefore, the existing user program has 2GB
It is desired to provide a means to facilitate conversion, ie, "address extension migration" to enable the use of a virtual space.

Before explaining the details of the present invention, a conventional dynamic link structure related to the present invention will be explained with reference to FIG.

In FIG. 4, 10 is the calling module;
11 is a branch and link instruction, 12 is a V format address constant, 13 is a dynamic link table, 1
4 is a name entry created corresponding to the called module, 15 is a linkage entry used in call processing, 20 is a called module, 2
1 is a branch instruction; 22 is a program management section in the control program to which control is passed during dynamic linking; 23
27 represents a loader that loads the load module into the main memory, and a library in which the load module is stored.

When the calling module 10 needs to call the called module 20 and transfer control, it specifies the entry point name XYZ of the called module 20 using the V format address constant 12 in advance. If this designation is made, the dynamic link table 13 is created by the linkage editor during link editing. In this dynamic link table 13,
A name entry 14 is provided corresponding to a V-format address constant whose address is unresolved, and finally a linkage entry 15 is provided.

In the name entry 14, an instruction 14A that branches to the beginning of the linkage entry 15, an entry point address (initial value = 0), and an entry point name are set.
a supervisor call (SVC) instruction that calls 2;
an instruction that loads the entry point address into a register;
An instruction to branch to the entry point address is set in advance.

The operation in dynamic linking is as follows.

When the calling module 10 specifies the V-format address constant 12 in the register R15 and issues a branch-and-link instruction 11, control is transferred to the name entry 14.

When the called module 20 is called for the first time, the branch instruction 14A points to the beginning of the linkage entry 15.
SVC instruction is executed.

As a result, the program management unit 22 is activated, and the program management unit 22 loads the called module 20 from the library 27 into the main memory using the loader 23, and adds 2 to the displacement disp of the branch instruction 14A. . Furthermore, since the entry point address of the called module 20 is determined, the entry point address is set in the name entry 14.

Upon return from the program management unit 22, a load instruction for the entry point address is executed.

Control is then passed to the entry point (XYZ) of the called module 20 by the branch instruction.
When the processing by the called module 20 is completed, control is returned by the branch instruction 21 after the branch and link instruction 11 of the calling module 10.

When the calling module 10 calls the called module 20 again, the branch instruction 14
Since the displacement of A has been updated, the program management section 22 is not called, and control is directly transferred to the called module 20 via the linkage entry 15.

It goes without saying that the conventional dynamic link described above is effective only when the operating modes of the addresses of the caller and callee are the same.

[Means for solving problems]

The present invention aims to solve the above-mentioned problems, and automatically switches the address mode during dynamic linking without modifying the user program. For example, a user program running in a 16MB virtual space can It provides a means to facilitate address expansion migration that allows the use of 2GB of virtual space.

FIG. 1 shows a block diagram of the principle of the present invention.

In FIG. 1, the same reference numerals as in FIG. 4 correspond to those shown in FIG. Reference numeral 16 indicates an extended transition entry assigned by the program management unit 22 for dynamic linking between modules with different operating modes, 17 indicates an instruction to load an entry point address into a predetermined register, and 18 indicates an extended branch with address switching. 24 is a mode determination unit that determines whether the operating modes of the addresses of the calling module 10 and the calling module 20 are different; 25 is a mode determining unit that determines whether the operating modes of the calling module 10 and the calling module 20 are different;
An extended migration entry allocation unit 26 dynamically allocates the extended migration entry 16 to the dynamic link table 13 so that the extended migration entry 16 receives control from the branch instruction of the dynamic link table 13. Represents the table update unit to be updated.

Even if the operation mode of the address of the called module 20 is different from the automatic operation mode, the calling module 10 instructs dynamic linking using the same interface as the conventional one. In the case of the present invention, after the loader 23 loads the called module 20 from the library 27, the mode determination unit 2
4, the operation mode of the called module 20 is determined. And the calling module 10
If the operation mode is different from the operation mode, the expansion migration entry allocation section 25 is activated. After the extended migration entry allocation unit 25 prepares the extended migration entry 16, the table update unit 26 assigns the extended migration entry 16 from the dynamic link table 13.
The dynamic link table 13 is updated so that control is transferred to. That is, calling module 1
When control is transferred from 0 to the called module 20, the extended transfer entry 16 automatically intervenes, and the extended branch instruction 18 switches the address mode.

The operation during dynamic linking is as follows. The numbers attached to the drawings correspond to the explanatory numbers below.

The branch and link instruction 11 transfers control to the beginning of the name entry 14 specified by the V-format address constant 12.

The branch instruction 14A initially points to the head of the linkage entry 15, and control is transferred to the linkage entry 15.

The program management section 22 is activated by the SVC command (SVC number=45).

(i) The loader 23 loads the called module 20 from the library 27.

(ii) The mode determination unit 24 determines the operation mode of the address, and when the operation modes are different, activates the expansion migration entry allocation unit 25.

(iii) The table update unit 26 stores the entry point address of the called module 20 in the entry 16 for extension migration, and sets the start address of the entry 16 for extension migration in the entry point address setting part 14B of the name entry 14. . The branch instruction 14A is updated to point after the SVC instruction.

Upon return of control from the program management section 22, data in the entry point address setting section 14B is loaded.

Since the data in the entry point address setting unit 14B is the start address of the extended migration entry 16, the instruction 17 for loading the actual entry point address and the extended branch instruction 18 are executed.

The extended branch instruction 18 switches the address mode and switches the called module 20.
Control is passed to

When calling the called module 20 for the second and subsequent times, the execution of the SVC instruction is omitted and the called module 20 is called via the linkage entry 15 and the expansion migration entry 16.

Alternatively, the table update unit 26 updates the table as follows, and the expansion migration entry 1
6 may be interposed. That is, the entry point address of the called module 20 is stored in the entry point address setting section 14B, and the branch instruction 1 is
The branch destination address is set so that 4A branches to the expansion migration entry 16. This results in 2
At the time of the subsequent call, control is transferred from the branch instruction 14A to the extended migration entry 16 without passing through the linkage entry 15, and the called module 20 is called by the extended branch instruction 18.

[Effect]

In a program with a dynamic link structure, modules are subdivided, unlike in the case of static link. Then, each module is loaded by the program management section 22 of the control program at the time of request, and control is transferred. The present invention has been made with this point in mind. In dynamic linking, the program management section 22 is always involved first, so the program management section 22 determines the operation mode related to the address mode and sets the address mode. By dynamically adding a switching instruction issuing mechanism, that is, an expansion migration entry 16, the address mode can be switched and control can be transferred to the called module without the user program being aware of it. Therefore, it is possible to extend the addresses of the subdivided modules step by step for each module as necessary.

〔Example〕

FIG. 2 is a diagram for explaining one embodiment of the present invention, and FIG. 3 is a diagram for explaining another embodiment of the present invention.

The embodiment shown in FIG.
When calling the called module 20 from 0,
Furthermore, when the called module 20 returns to the called module 10, the address mode is automatically switched.

Initially, the dynamic link table 13 is configured as shown in FIG.

The calling module 10 says “L 15,
When you issue the “VCON” command, name entry 1
The address of 4 is loaded into register R15,
The "BALR 14, 15" instruction sets the return address in register R14 and branches to branch instruction 14A. Next, control is passed from branch instruction 14A to "SVC 45" instruction,
Program management takes control.

In the case of this embodiment, the program management section stores the extension table 30 in which the entry 16 for extension migration is set.
It is determined whether or not the name entry 1 has already been secured, and if it has not been secured, the extension table 30 is cut out from the user area, etc., and name entry 1 is stored in it.
4, an entry 16 for expansion migration is prepared. Then, the dynamic link table 13 is
Update as shown in Figure B. That is, branch instruction 14
The displacement of A is set to "a+2", and the start address of the expansion migration entry 16 is set in the entry point address setting section 14B. The expansion migration entry 16 is provided with an entry point address setting section 19 that replaces the save area of the register R14 and the entry point address setting section 14B, and the entry point address of the called module 20 is set in the setting section 19. Ru.

When the "L 15, 4, 15" instruction is executed by returning from the "SVC 45" instruction or branching by the second or subsequent branch instruction 14A,
The address of the expansion migration entry 16 is set in the register R15. And “BR 15”
The command transfers control to the expansion transfer entry 16.

The instruction a in the expansion migration entry 16 is an instruction to save the register R14, which would be destroyed during linking, to the area f. Instruction b is instruction 17 that loads the entry point address, and loads the contents of area g into register R15. Instruction c is an extended branch instruction 18, and in particular is an instruction to save the return address to register R14, switch the address mode, and branch to the address in register R15.

Upon return from the called module 20, control is passed to instruction d, which restores the contents of register R14 from area f. Thereafter, control is returned to the calling module 10 by command e. Instruction e is one of the extended branch instructions and is a branch instruction that involves address mode switching. Thereby, even when control is returned to the calling module 10, switching to the original address mode is automatically performed.

The embodiment shown in FIG.
0 to the calling module 10, the called module 20 explicitly issues an extended branch instruction with address mode switching, and returns control directly to the calling module 10. The differences from the embodiment shown in FIG. 2 are as follows.

Only one extended migration entry 16 is provided, for example, in the fixed address area, which is the first page of the virtual space. And the called module 2
When the program management section is activated by the first dynamic link to 0, the program management section updates the dynamic link table 13 from the state shown in FIG. 3A to the state shown in FIG. 3B. do. That is, branch instruction 1
The branch destination of 4A is set to the start address FICE of the expansion migration entry 16. Entry point address setting section 1
4B is the entry point of the called module 20 (XYZ)
Set address. Further, the address mode is displayed 14B' in the first bit of the entry point address setting section 14B. In other words, the first 1 bit is “1”
to remember that it is extended address mode.

When the branch instruction 14A is executed after the dynamic link table 13 is updated, the expansion migration entry 1
6, the control is transferred to the entry point address setting unit 14 by the instruction 17 to load the entry point address.
The contents of B are loaded. Then, by the "BX 0, 15" instruction, which is the extended branch instruction 18, the address mode is switched and the called module 20
Branches to are executed simultaneously.

For example, when calling a 31-bit mode module (hereinafter referred to as new module) from a 24-bit mode module (hereinafter referred to as old module), the new module is a newly created or modified module, so The embodiment shown in FIG. 3 can be used. The embodiment shown in FIG. 2 is convenient when calling an old module from a new module by dynamic linking. It is also possible to implement the embodiment shown in FIG. 2 and the embodiment shown in FIG. 3 together. In this case, the program management section uses the expansion migration entry 16 depending on the combination of operation modes between modules. Of course, if address mode switching is not necessary, the extended migration entry 16 is not used.
It can be considered that dynamic link control is performed in the same way as in the past.

〔Effect of the invention〕

As explained above, according to the present invention, an extended branch instruction issuing mechanism that automatically switches the address mode during dynamic linking is provided, so that, for example,
Control can be transferred between the old module in 24-bit mode and the new module in 31-bit mode without any modification to the old module. Therefore, the existing user program
Conversion to enable the use of the old large virtual space, that is, address expansion migration, can be performed in stages from appropriate modules as needed, greatly reducing the time and effort required to modify modules. It becomes possible to do so.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a diagram for explaining one embodiment of the present invention, FIG. 3 is a diagram for explaining another embodiment of the present invention, and FIG. 4 is a diagram for explaining another embodiment of the present invention. is a diagram explaining a conventional dynamic link structure. In the figure, 10 is the calling module, 13 is the dynamic link table, 14 is the name entry, and 15 is the calling module.
is a linkage entry, 16 is an extended migration entry, 18 is an extended branch instruction, 20 is a called module, 22 is a program management section, 23 is a loader,
Reference numeral 24 represents a mode determination unit, 25 represents an expansion migration entry allocation unit, 26 represents a table update unit, and 27 represents a library.

Claims (1)

[Scope of Claims] 1. A computer system that has multiple running address mode attributes with different upper limits of virtual space and is equipped with an extended branch instruction mechanism that switches the address modes, wherein the call destination of a dynamic link target A name entry 14 in which entry point information is stored, and a linkage entry 15 provided with an instruction to call the program management unit 22 that processes dynamic linking and a branch instruction.
In a computer system in which a dynamic link is controlled by a dynamic link cable 13 having a means 24 for determining whether the operating modes with respect to the address modes are different; when the operating modes are different, at least an instruction 17 for loading the call destination entry point address stored in a predetermined area into a predetermined register; A means 25 for allocating an extended migration entry 16 storing an instruction code string including an extended branch instruction 18 with switching, and a control transfer destination in the dynamic link cable 13 are stored in the extended migration entry 16. and a means 26 for updating the dynamic link table 13 so that the instruction code string is at the beginning of the instruction code string stored in the entry 16, so that the address mode is switched by executing the instruction code string stored in the expansion migration entry 16. An address mode switching control method using a dynamic link, which is characterized by: