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Information in this article applies to:

  • C51 All Versions


I'm currently working on an interrupt service routine that has a challenging timing requirement. After compiling the routine and looking at the assembly listing I noticed that the complier chose a different CJNE instruction than I would have.

I was wondering if there was an easy way to modify the assembled code by changing a few of the assembly lines without having to re-write the whole routine in assmebly?


You can write your code in C, then use the SRC directive to have the compiler generate an assembly module for your C code. You may modify the generated assembly file and include that in your project. Note that once you modify this file, you should not regenerate it with the C file because that would overwrite your changes.


  • Refer to SRC in the Cx51 User's Guide.
  • Refer to CJNE in the 8051 Instruction Set Manual.


The following Discussion Forum threads may provide information related to this topic.

Last Reviewed: Thursday, September 22, 2005

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