Declares the entry point of a called routine to the compiler.
    This entry declaration will save and restore the full 64 bits of
    any registers (except R0 and R1) that are modified by the routine
    and are not declared as scratch or output.

    Format

      .CALL_ENTRY  [max_args=number] [,home_args=TRUE|FALSE]

                   [,quad_args=TRUE|FALSE] [,input] [,output]

                   [,scratch] [,preserve] [,label]