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I have a 32-bit ARM Linux kernel module with debug symbols. When it is decompiled, it produces many functions that have a macro called MEMORY in them. Here is an example:

int S_u8init_flag = 0; // Context for function internals
int aess_adcsensor_release(inode *inode, file *filp) {
  int result;

  result = 0;
  MEMORY[0xF0014000] &= 0xFFFDFFFF; // What does this mean?
  S_u8init_flag = 0;
  return result;
}

What does this MEMORY macro mean? Is there a C99 equivalent to it, or is it an IDA-specific macro?

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MEMORY[<addr>] means there is a direct access to a memory address which is not mapped to an existing segment in the IDB so the decompiler/IDA could not allocate a variable for it.

If you press Tab, you should land on the assembly corresponding to that line and check what is happening there.

  • Thank you! This is perfect. I assume that you would just assign it to a variable to allow comparisons like the one in the code sample, right? – nhubbard May 14 at 18:45

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