Labeled USING domains
You can specify the same base register or registers in any number of labeled USING instructions. However, unlike ordinary USING instructions, as long as all the labeled USINGs have unique labels, the assembler considers the domains of all the labeled USINGs to be active and their labels can be used as qualifiers. With ordinary USINGs, when you specify the same base register in a subsequent USING instruction, the domain of the prior USING is ended.
The domain of a labeled USING instruction continues until the end
of a source module, except when:
- You specify the label in the operand of a subsequent DROP instruction.
- You specify the same label in a subsequent USING instruction.