VMS Help MACRO, VAX MACRO Assembler, Instructions, JSB  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Purpose:        Jump to subroutine - transfer control to subroutine
    Format:         opcode dst.ab
    Operation:      -(SP) = PC; PC = dst
    C. Codes:       Not affected
    Exceptions:     None
    Opcode:         16    JSB      Jump to subroutine
    Description:    PC is pushed onto the stack as a longword and the
                    jump is taken.