You can use the built-in variable {ARMASM_VERSION} to distinguish between versions of armasm. The format of the version number is PVbbbb where:

The assembler did not have the built-in variable |ads$version| before ADS and RVCT. If you have to build versions of your code using legacy development tools, you can test for the built-in variable |ads$version|. If this variable is not defined, then the assembler is part of a legacy development toolchain. Use code similar to the following:

    IF :DEF: |ads$version|
      ; code for RealView or ADS
    ELSE
      ; code for SDT (a legacy development toolchain)
    ENDIF