This class is oriented to the advanced Assembler language programmer that includes updated information relating to features with HLASM and the requirements of writing 31-bit programs. Specific topics will focus on the modal instructions and how information and control are exchanged between 24-bit and 31-bit programs. In addition, the discussion will include topics that relate to restrictions and considerations for programs in different modal states. This course is a workshop environment where classroom projects will involve writing 31-bit programs
Students should have a good understanding of basic OS/390 architecture.
5 Days/Lecture & Lab
This class is intended for experienced assembler language programmers.
- Overview of OS/390 31-bit architecture
- Modal instructions and addressing modes
- AMODE vs RMODE
- Using storage above the 16 MB line
- Virtual storage allocation (GETMAIN/FREEMAIN)
- Assembler coding considerations for 31-bit addressing
- Assembler coding considerations for coexistence with 24-bit programs
- Sharing data in virtual storage (IARVSERV)
- Data management considerations for 24/31 bit programs
- 31-bit specific macros and instructions
- Linkage stack
- Overview of changes in z/OS 64-bit addressing