JPH0452974B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] A vector selection method that selects and operates vector tables of different basic systems. Ru
By storing a specification flag specifying the basic system of the program loaded in RAM, and selecting and specifying the vector table necessary for the basic system by referring to the specification flag using the selection means,
Allows operation of different basic systems.

[Industrial application field]

The present invention relates to a device in which a basic system is stored in a ROM, and more particularly to a vector selection method that can select and operate vector tables of different basic systems.

A device with a basic system stored in ROM may have a different basic system or an old system stored in ROM.
There is a need for a method that can be operated without replacing the parts.

[Conventional technology]

FIG. 3 shows a block diagram of a conventional device 1 in which a basic system is stored in a ROM.

In the figure, 2a is a ROM in which the basic system A is stored. 3a is RAM and basic system A
The program and vector table used are loaded. The vector table is a table that specifies a program storage area.

Therefore, the basic system A operates according to the program in the area designated by the vector table stored in the RAM 3a.

[Problem that the invention seeks to solve]

According to the above conventional method, only one vector table exists for one basic system in this device. Therefore, in order to operate a different basic system, there is a problem that it is necessary to replace the ROM 2a and create a new vector table suitable for the basic system.

[Means for solving problems] FIG. 1 is a block diagram of the principle of the present invention.

In the figure, reference numeral 2 denotes a first storage unit which stores a plurality of basic systems and also stores selection means 4 for selecting a vector table used in the basic system, and is composed of a ROM.

Reference numeral 3 denotes a second storage unit, which is composed of a RAM, into which the program and vector table used for the basic system are loaded and at the same time the basic system of the program is designated by the designation flag 5.

Therefore, the selection means 4 is configured to refer to the designation flag 5 and select the vector table of the basic system designated by the designation flag 5.

[Effect]

When using any of the multiple basic systems,
The selection means 4 refers to the designation flag 5 and selects the vector table of the basic system in the second storage unit 3 based on the designation of the designation flag 5 in the second storage unit 3, thereby selecting a different basic system from the ROM. exchange,
and can be used without creating a new vector table.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the block diagram of FIG. The same reference numerals as in FIGS. 1 and 3 indicate the same objects. In FIG. 2, parts corresponding to those in FIG. 1 are shown surrounded by a dashed line.

In the figure, device 1a has ROM 2b and
Equipped with RAM3b.

ROM2b is the input initial program load (IPL)
A loader 6 for loading the data into the RAM 3b, basic systems A and B, and a vector table selection section 4a are stored.

The RAM 3b is loaded with the program of the basic system to be used, and either the basic system A or B of the program is specified in the designation flag 5a.

The vector table selection unit 4a is configured by the loader 6.
When IPL to RAM3b is completed, it starts and RAM3
With reference to the designated flag 5a of b, the designated flag 5a
Select the vector table required for either basic system A or B specified in . Furthermore, if the basic system in the ROM 2b expects the vector table to exist in a predetermined area on the RAM 3b, the vector table is moved to the predetermined area.
Furthermore, even after the basic system is started, switching is possible upon request from the program in the RAM 3b.

With such a configuration and function, the IPL of either basic system A or B used is RAM
3b and the vector table of the basic system is specified in the specification flag 5a, the vector table selection unit 4a refers to the specification flag 5a and selects the specified basic system before starting the basic system. Select and start the vector table of either system A or B.

In this way different basic systems can be operated.

Furthermore, even after the basic system is started, the interrupt processing and the like in the ROM 2b can be switched and used by the designation flag 5a, which is extremely effective.

〔Effect of the invention〕

As explained above, according to the present invention, a different basic system can be used without replacing the ROM or creating a new vector table.

Even after the basic system is started, interrupt processing in the ROM can be switched and used using designated flags.

There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a block diagram showing a conventional example. In the figure, 2 is the first storage unit, 2a and 2b are
ROM, 3 is the second storage section, 3a, 3b are RAM,
4 is a selection means, 4a is a vector table selection unit,
5 and 5a are designation flags, 6 is a loader, and A and B are basic systems.

Claims (1)

[Claims] 1. A first storage unit 2 that stores a plurality of basic systems and a selection means 4 that selects a vector table used in the basic system, and a program used in the basic system. and a second storage unit 3 in which the basic system of the program is designated by the designation flag 5 at the same time as the vector table is loaded, and when using any of the plurality of basic systems, the selection means 4 A vector selection method characterized in that the designation flag 5 is referred to and a vector table necessary for the basic system is selected based on the designation of the designation flag 5.