JPS62121549A - High speed system for os simulator - Google Patents

Abstract

PURPOSE:To make the speed of a branching high by providing a branching table indicating a branching destination every system call during issuing the system call and a flag register indicating whether the branching table is used or not. CONSTITUTION:When an application task issues the system call, a software interruption is generated, a control is moved to a program registered for the software interruption and branched to a system call processing sorted and designated according to a system call number contained in a register 2 in the program. In the siftware interruption program, the system call is sorted and branched to respective simulation programs 4. During the generation of the software interruption, according to the system call number in the register, the respective system calls are branched automatically to the simulation programs 4.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is applicable to applications and applications in computer systems.
When a program issues a system call of a heterogeneous operating system 11, it involves providing a branch table that indicates the branch destination for each type of system call, and is suitable for speeding up the simulation of an operating system. Regarding the method.

[Background of the invention]

The functions of vectors, tables, and tables in conventional microcomputers are as described in the document R68000 Microcomputer (Maruzen, published in March 1988), when a software interrupt occurs, the corresponding vector and table are
Control is transferred directly to an address within the table.

However, no consideration was given to a method of transferring control to an address in another table indicated by a vector table (indirect jump).

[Purpose of the invention]

An object of the present invention is to provide a mechanism for quickly branching to each simulation program that simulates system calls in OS simulation in a computer system.

[Summary of the invention]

A system call interface in a general-purpose microcomputer is generally realized by storing a number representing the type of system call in a register and generating a software interrupt instruction. When an application task issues a system call, a software interrupt occurs and control is transferred to a program registered for that software interrupt. Then, within the program, the system call processing is classified according to the system call number contained in the register and branched to the specified system call processing. To realize OS simulation using this method, system calls must be classified within the software interrupt program and branched to each simulation program. Therefore, we thought of doing these things faster with firmware, and when a software interrupt occurs, the system in the register! We devised a method to automatically branch to a simulation program for each system call, depending on the call number.

[Practical side of the invention]

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a method of configuring an OS simulator in a computer system. Vector table 1 contains the trap (
Trap) instruction (Motorola 16-bit microcontroller 6
If you register the address of the program to which control is transferred when a software interrupt or hardware interrupt occurs (such as a 8000 instruction), it is a table that is assigned to a fixed address in terms of hardware. Register 2 is a general-purpose register within the microcomputer and contains a system call number.

Branch table 3 registers the address of the simulation program to which control should be transferred when a software interrupt occurs. The simulation program 4 is a program that simulates each system call.

Simulation flag 5 is a flag that specifies a branching method using a vector table.

FIG. 2 shows a software interrupt instruction (in this example, Tr
This is a flowchart showing the operation of the firmware when the ap instruction) is executed. The procedure is as follows. (1) Save the PC (program counter) and SR (status register) to the supervisor stack when a software interrupt occurs (21). (2) Check whether the simulation flag is on (22). (3
) If it is off, set the SR mode to supervisor mode as in conventional processing25) and transfer control to the address of the contents of the vector table pointed to by the Trap number (25).
6). (4) If it is on, move the PC and SR loaded on the supervisor stack to the user stack (
23). Find the starting address of the branch table where the contents of the vector table pointed to by the Trap number are increased. Register (2 in Figure 1)
Control is transferred to the address of the content contained in the entry in the branch table indicated by the system code possessed by (24). The simulation flag is set on/off by the program.

In this way, by having a corresponding branch table for each system code, it is possible to branch to a simulation program for each system call with a single software interrupt instruction.

〔Effect of the invention〕

According to the present invention, in OS simulation, it is possible to branch to each simulation program with a single software interrupt instruction, which has the effect of improving the performance of the simulator.

[Brief explanation of drawings]

FIG. 1 shows a method of configuring an OS simulator in a computer system. FIG. 2 is a flowchart of firmware operations when a software interrupt instruction is executed.

Claims (1)

[Claims] In an operating system that controls multiple tasks, multiple application tasks including an operating system simulator (OS simulator) running under the multiple application tasks, and an information processing device that supports the multiple application tasks, an application task may run under a different operating system. When a system call is issued to use a system function, in order to quickly branch to a simulation program according to the system call, a branch table indicating the branch destination for each system call and its A method for increasing the speed of an OS simulator, characterized by providing a flag register indicating whether or not to use a branch table.