cos的命令处理流程（Cos command processing flow）.docVIP

cos的命令处理流程（Cos command processing flow） The command process COS (map) published: 2008-10-20 13:38:58 Category: software development technology 1, work principle The command process is highly ordered to carry out process, handle it according to the command categories and application categories call different command processing module command. Its main function is according to the command message in the input buffer command parameters and input data. Continue to respond to the operation, and the results will be executed and the response data on the response data output buffer. There are two different ways of command call processing module: * function call; * interrupt. According to the chip platform programming environment, two kinds of methods can be selected, the main difference is that: * function call, parameters and results of passing through the stack, the stack size has certain requirements, but can not transfer the data object is too large. * interrupt call transfer parameters and results through a fixed buffer to reduce the use of the stack, more flexible, but need to program from the interpretation of the data buffer structure. The following example introduces the design of interruption. 2, the command process design example As shown in Figure 1, the whole process is divided into the following steps: Figure 1 command processing example 1) CLA validity inspection The command message command input buffer, first check the CLA command byte is legitimate, the only legitimate CLA bytes 0x00, 0x04, 0x80 and 0x84 in four cases, if CLA is illegal, return error code. 2) according to the INS command processing module entrance address lookup According to the INS find entrance address lookup processing module, see below. If the search fails, indicates that the corresponding INS error, return error code. If the search is successful, continue to the next step. 3) command processing According to the command processing module to find the entrance of the address, call the cor