Specifying the source data set: SYSIN
Define the data sets that contain your source code with the SYSIN
DD statement:
//SYSIN DD DSN=datasetname,DISP=SHR
This data set contains the input to the assembler; that is, the assembler language source statements to be processed.
You can place your assembler source code in the input stream.
To do this, use this SYSIN DD statement:
//SYSIN DD *
When you use the (*) DD parameter, the source code must follow the DD statement. If another job step follows the assembly, the EXEC statement for that step must follow the last source statement, or end-of-file (/*) statement.
The IBM-supplied High Level Assembler procedures do not contain
the SYSIN DD statement. The DD statement for SYSIN must be provided
in the input stream:
//STEP1 EXEC ASMAC
//SYSIN DD *
⋮
assembler source statements
⋮
/*