JPS6344246A - Electronic computer - Google Patents

Abstract

PURPOSE:To realize the fast switching of a process, by performing the saving of an execution environment, the selection of the next process, and the loading of the execution environment on a second register group, before the switching of the process. CONSTITUTION:When the switching of the process is generated, a central processing unit 1, after switching a register group 11 to a register group 12, preserves the execution environment stored in the register group 11, in a main memory device 2. The switching of the process is completed by selecting the process to be executed at a next stage, and issuing an instruction to instruct the read-in of the execution environment to the register group 11, to a process managing device 3. In parallel with the execution of the next process at the central processing unit 1, the process managing device 3 accesses to the register group 11, and the main memory device 2 through a data bus 21, and a system bus 4, then preserves the execution environment, and performs the selection of the process, and the read-in of the execution environment.

Description

[Detailed description of the invention] Industrial applications The present invention relates to electronic computers.

BACKGROUND OF THE INVENTION Conventional electronic computers switch processes by having a central processing unit sequentially execute the following three steps. In the first step, the execution environment stored in a group of registers on the central processing unit, including general-purpose registers, program counters, status registers, etc., is saved in the main memory. In the second step, the process with the highest priority among the executable processes is selected according to the process priority data held in the main memory. In the third step, the execution environment of the process selected in the second step was retrieved from the main memory and read into the register group.

Problems to be Solved by the Invention However, since conventional electronic computers sequentially execute the three steps when switching processes as described above, it is not possible to switch processes at high speed.

In particular, in large-scale TSS systems, process switching occurs frequently, resulting in a large overhead in process switching time, which reduces system efficiency. The present invention has been made in view of these problems, and it is an object of the present invention to provide an electronic computer that can perform process switching at high speed.

Means for Solving the Problems The present invention has two sets of registers for storing the execution environment of a process, and an access means for directly accessing the registers from outside the central processing unit. a central processing unit that selects and uses one register group from the two sets of registers that holds the execution environment of the process; a storage device that stores the execution environment of each process and holds the priority of each process; Prior to process switching performed by the processing unit, the access means is used to directly access the register group that is not selected by the central processing unit, independently of the execution of the process on the central processing unit, and select the register group that is not selected by the central processing unit. After saving the execution environment held in the storage device to the storage device, a process to be executed next on the central processing unit is selected according to the priority order, and the execution environment of the process is saved from the storage device to the register. The central processing unit loads the execution environment of the process to be executed next by the process control unit from the register group that has been selected and used for the execution of the process. The electronic computer is characterized in that the process is switched by switching to a register group that is currently being used, and the execution of the next process is started using the register group.

Effects The effects of the present invention are as follows. Until a process switch occurs, the execution environment of the currently executing process exists in the first register group. Prior to process switching, the process management device saves the execution environment, selects the next process, and loads the execution environment of the process in the second register group. In this way,
Since the execution environment of the next process to be executed is stored in the registers not selected by the central processing unit, the process can be switched only by switching the selected register. Therefore, high-speed process switching is realized.

The embodiment diagram is a block diagram showing an embodiment of the electronic computer of the present invention. Central processing unit 1 has two register groups 11 and 12. 2 is a main storage device that stores the execution environment of each process, and 03 is a process control device that maintains the priority of each process.

21 is a data bus for the process control device to access a register group in the central processing unit; 22 is a control signal line from the central processing unit to the process control device;
3 is a control signal line from the process control device to the central processing unit. Central processing unit 1 , main memory 2 , and process control unit 3 communicate via system bus 4 .

Assume that a process being executed is using the register group 11, and the execution environment of the next process to be executed is stored in the register group 12 in advance.

When a process switch occurs, the central processing unit 1
After switching the register group used as the execution environment of the running process to the register group 12, the execution environment stored in the register group 11 is saved in the main storage device 2, and the next process to be executed is selected. By issuing a command to the process management device 3 via the control signal line 22 to read the execution environment into the register group 11, the process switching operation of the central processing unit 1 is completed and the next process is started. Start execution. In parallel with the execution of the next process on the central processing unit 1, the process is executed by accessing the register group 11 and the main memory 2 via the data bus 21 and system bus 4. The environment is saved, the main memory 2 is accessed via the system bus 4 to select a process, and the register group 11 and the main memory 2 are accessed via the system bus 4 and the data bus 21 to save the execution environment. Read. When the process management device 3 completes the above three steps, it sends an acknowledgment to the central processing device 1 via the control signal line 23.

In order to avoid access conflicts with the process management device 2, the central processing unit 1 cannot access data regarding the execution environment and priority of the process in the main storage device 2 until this acknowledgment is returned.

As described above, since the overhead of process switching can be reduced to only the time for issuing commands to the process management device and the time for switching register groups, high-speed process switching is realized. Furthermore, according to the present invention, process switching can be performed at high speed, which is extremely effective in practice.

[Brief explanation of drawings]

The figure is a block diagram of an embodiment of the electronic computer of the present invention. 1... Central processing unit, 2... Main storage device, 3... Process management device, 4... System bus, 11゜12... Register group, 21・
・River・Data bus, 22゜23・・・・Control signal line. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
121 Engraving of Figure 7 (no change in content) Written amendment to register procedure (method) % formula % 1 Display of the case 1985 Patent Application No. 187116 2 Name of the invention Computer 3 Relationship with the person making the amendment Patent Application Address 1006 Kadoma, Kadoma City, Osaka Prefecture Name
(582) Matsushita Electric Industrial Co., Ltd. Representative Akio Tanii 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Date 6 of the amendment order, contents of the amendment (1) Specification Correct "Figure wa" in the 5th line of page 8 to "Figure 1 wa". ('4 The drawing has been corrected to "Figure 1" and the figure number has been added as shown in the attached sheet.

Claims (1)

[Claims] It has two sets of registers for storing the execution environment of a process, and an access means for directly accessing the registers from outside the central processing unit, and the two sets of registers for holding the execution environment of the process being executed are provided. a central processing unit that selects and uses one set of registers from a group of registers; a storage device that stores the execution environment of each process and maintains the priority of each process; Using the access means, the register group not selected by the central processing unit is directly accessed independently of the execution of the process on the central processing unit, and the execution environment held in the register group is transferred to the storage device. a process management device that selects a process to be executed next on the central processing unit according to the priority order after saving, and loads the execution environment of the process from the storage device into the register; The device switches from the registers that have been selected and used for process execution to the registers loaded with the execution environment of the process to be executed next by the process control device. 1. An electronic computer characterized in that the register group is used to start execution of the next process.