A source module is composed of source statements in the assembler language. You can include these statements in the source module in two ways:

• You can enter them directly into the file that contains your source program.
• You specify one or more COPY instructions among the source statements being entered. When High Level Assembler encounters a COPY instruction, it replaces the COPY instruction with a predetermined set of source statements from a library. These statements then become a part of the source module. See COPY instruction for more details.