Double CPU communication method based on shared memory

Abstract

The invention discloses a double-CPU communication method based on shared memorizer. A dual-way transmitting channel is arranged between a first CPU and a second CPU. Each channel uses two ring queues, with one for placing information index and the other one for placing information body; and each channel transmission includes the following steps: initialization flow: complete the initialization of the queue reading finger under the charge of the CPU; information transmission flow: write new information bodies into the queue of information body and upgrade the writing finger of information body queue, namely pointing to the usable unit behind the new information body; upgrade the content of the unit pointed by the writing finger of the information index queue, point to the new information body in the information body queue, and make the writing finger of information index queue to the next unit; and information-receiving flow. Because of introducing index queue and body queue into the shared memorizer, the invention supports the changeable length of information, thus lowering the waiting time of the sender and receiver, enhancing the utilization rate of CPU, and increasing the data throughput and handling speed.

Description

technical field [0001] The invention relates to a communication method in the technical field of communication, in particular to a dual-CPU communication method based on a shared memory. Background technique [0002] When two CPUs in the prior art communicate through a shared memory, there are currently two common methods. [0003] One method is to divide the shared storage area into two pieces, which are respectively used as the sending and receiving channels of the two CPUs, as shown in Figure 1. Each channel provides a read and write flag, which is initially writable. After sending the data, the sender changes the read-write flag from the writable state to the readable state, and waits for the receiver to receive it. After receiving the data, the receiver changes the read-write flag from the readable state to the writable state, so that the sender can continue to send. With this method, each data interaction needs to wait for the other party to finish reading or writin...

AI Technical Summary

Problems solved by technology

[0006] (1) Data is generally sent in packages of fixed length. The length of the message package varies greatly. For example, the minimum length is 4 bytes, and the maximum length is 40 bytes. They must be packaged and sent according to the maximum 40 bytes, resulting in waste.

[0007] (2) When the data is not packaged and sent according to the fixed length, the length information needs to be included in the message packet. Since the message packet has an indefinite length, the receiver cannot calculate the number of messages to be processed by reading and writing pointers

[0008] (3) When the length of the message packet is indeterminate, in the process of continuously sending messages, if one of them fails, all subsequent read and write pointers will be disordered

Conflicts arise if normal message packets contain special values

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