6.1.4.1 Special Comment Strings

Several comment strings are appended to compiler-generated assembly instructions by the code generator. These comments are typically used by the assembler optimizer.

The comment string ;volatile is used to indicate that the memory location being accessed in the instruction is associated with a variable that was declared as volatile in the C source code. Accesses to this location which appear to be redundant will not be removed by the assembler optimizer if this string is present.

This comment string can also be used in hand-written assembly source to achieve the same effect for locations defined and accessed in assembly code.

The comment string ;wreg free is placed on some call instructions. The string indicates that the W register was not loaded with a function parameter; i.e., it is not in use. If this string is present, optimizations can be made to assembler instructions before the function call, which loads the W register redundantly.