Declares a global label in a routine that is not an entry point to the routine. Format Label: .GLOBAL_LABEL There are no parameters for this directive.
1 – Description
The .GLOBAL_LABEL directive declares a global label within a routine that is not a routine entry point. Unless declared with .GLOBAL_LABEL, global labels in code (specified with "::") are assumed to be entry point labels, which require declaration. If they are not declared, they are flagged as errors. The compiler also allows the address of a global label to be stored (for instance, by means of PUSHAL instruction). (The compiler flags as an error any attempt to store a label that has not been declared as a global label or an entry point.) By using the .GLOBAL_LABEL directive, you are acknowledging that the stored code address will not be the target of a CALL or JSB instruction. Global labels must appear inside routine boundaries. Labels declared with the .GLOBAL_LABEL directive can be used as the newpc argument in calls to the $UNWIND (Unwind Call Stack) system service because it allows the address of the label to be stored. However, there is no provision in the compiler to automatically adjust the stack pointer at such labels to remove arguments passed on the stack or compensate for stack alignment. If the call stack is unwound back to an alternate PC in the calling routine, the stack may still contain arguments and alignment bytes, and any stack-based references that expect this adjustment to the caller's original stack depth (which happened automatically on VAX) will be incorrect. Code that contains labels declared with this directive that are to be used as alternate PC targets for $UNWIND must be examined carefully to ensure correct behavior, with particular emphasis on any references based on the stack pointer.