Entry

Entry is an 8-byte, 32-bit word pair variable consisting of a 4-byte descriptor pointer and a 4-byte frame pointer value. The descriptor pointer points to a data area that specifies the text address of the procedure entry and the table of contents pointer for the procedure. The frame pointer (relevant only with internal procedures) designates the stack frame of the containing procedure, if any. For external procedures, the frame pointer value is zero (0).