JPS6091474A - Exclusive control system for plural processors - Google Patents

Abstract

PURPOSE:To attain the exclusive control and to simplify the program production without having an access inhibition display area corresponding to a routine or a table requiring no exclusive control for each said routine or table, by making use of a control flag bit of each word. CONSTITUTION:An instruction is read out and decoded by a decoder DC, and the execution is through with the instruction. Then the address in a memory MM is decided by an address calculating circuit AD, and the contents mmi of an address word are read out to a reading buffer RBUF. At the same time, a control flag bit FLI of the corresponding address word is read out. When the value of the bit FLI is equal to ''1'', a gate circuit GT is closed. Thus the contents mmi are not read out to the buffer RBUF, and the instruction of an instruction executing register IC is executed again. The circuit GT is opened when the value of the bit FLI is set at ''0'' by another processor. Then the contents mmi of the memory MM are read out to the buffer RBUF and sent to the register IC to be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention provides read/write access to only a single processing unit when multiple processing units compete for the same main memory; The present invention relates to an exclusive control method that waits for read/write access, and particularly relates to a method of using control flags added to six words of the storage device to display access prohibition for exclusive control.

1. Prior Art When multiple processing units access the same main memory in a competitive manner, for example, while one of the processing units is executing an update process, the other processing units update at the same time until the update is completed. is not allowed and is therefore subject to exclusive control. Conventionally, exclusive control was applied to a specific word or specific byte for each update processing routine that required exclusive control of the program executed by each processing device, or for each update processing target table that required exclusive control. A prohibited access display area has been established. To start processing a routine or table that requires exclusion, first check whether there is an access prohibition display in the above access prohibition display area, and if there is already an access prohibition display, the access prohibition display is checked until the access prohibition display disappears. Repeat the inspection and when the access prohibition display disappears, a control terminal command is prepared for the next step command.
Thereafter, when the processing that requires exclusion is completed, the access prohibition display is deleted.

No. 1 Problems with the Prior Art In the prior art, a separate access-prohibited display area had to be prepared for each routine or table that required exclusive control. In addition, programs that require exclusive control store the access prohibition display area provided for each exclusive control routine or table in correspondence with the items that need to be prohibited.
I had to choose.

21 Object of the Invention The object of the invention is to utilize canned control flag bits without separately preparing a corresponding access prohibited display area for each routine or table that requires exclusive control, and to simplify the creation of exclusive control programs. The purpose is to

E1 A detailed explanatory diagram of the present invention is a configuration diagram of an embodiment of exclusive control of a plurality of processing devices based on the present invention. In the figure, the storage device MM has a flag part FL at each position, and the part excluding the storage device MM is one processing device CPUI, and in reality, there are multiple processing devices with the same configuration shown here. .

When an instruction is read into the instruction execution register IC, decoded by the decoder DC, and instruction execution is completed, the address in the memory device MM is determined by the address calculation circuit AI), and the content capacity of the address word in the memory device MM is determined. ml is read into read buffer RBUF. At the same time, the control flag part λ bit FLI of the address word is read out, and if the value of the flag bit FLJ/ is "1', the gate circuit GT is closed and the address content mi is stored in the read buffer RBUF". The instruction in the instruction execution register C is executed again. When another processing device sets the value of the flag bit F'IJ to "0#," the gate circuit GT opens and the memory device MM
The content amount mi is read out to the successive buffer RBUF'' and sent to the instruction execution register C for execution.In addition, instructions for turning on and off flag bits are executed in the flag bit on and off circuit SA as in the prior art. Ru.

Effects of the Invention When multiple processing devices access the same storage device using exclusive control, there is no need to secure a special access-prohibited display area for exclusive control as in the past. It is no longer necessary to select and specify the access-prohibited display area when creating a program.In particular, for routines that you want to execute exclusively, simply specify that the access-prohibited display area be added to the flag section of the routine's start command. An access prohibition indication can be added to the flag section of the word for each item of the table that is desired to be updated frequently or exclusively.

In the figure, MM is a memory code shared by multiple processing devices, and SA is a flag on/off circuit.

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Claims (1)

[Claims] In a multiprocessor in which a plurality of processing units access a storage device that has a control flag for each word, when the plurality of processing units access the same word simultaneously, the control flag bit for that word is turned on and off. An exclusive control method for multiprocessors characterized by exclusive control of access conflicts.