.ENABLE enables the specified assembly function. .ENABLE and
    its negative form, .DISABLE, control the following assembler
    functions:

    o  Creating local label blocks

    o  Specifying that undefined symbol references are external
       references

    o  Enabling or disabling specific optimizations for the assembly
       unit

    You can enable one or more specific optimization options with
    either the .ENABLE directive or the /OPTIMIZE command-line
    qualifier, or both. If you explicitly disable one or more
    specific optimization options with the .DISABLE directive, those
    optimization options are disabled regardless of the command-line
    options you specify.