An assembler program can contain user instructions. They perform application-specific operations. User instructions biuniqely correspond to instruction classes held in the instruction class set of a node that can contain the assembler program. Before searching an instruction class in the instruction class set while assembling the program, the assembler normalizes a user instruction parameters string according to the rules described in Setting the Instruction Parameters String.
You can split the parameters string of a user instruction into multiple lines at positions of commas contained not within string literals. To indicate that a line of a parameters string is continued on the next line, terminate the continued line with a comma after an instruction parameter.