AppliedProgramming32 min
Assembler (HLASM) fundamentals
The machine's own language, made readable. Why assembler still runs exits and critical modules, how registers and base addressing work, the instructions and linkage you will meet most, and how to read assembler in a dump.
What you will be able to do
- Explain where assembler is still used and why it matters for dumps and exits
- Read common instructions, branch masks and base-displacement addresses
- Follow standard linkage: save areas, R1 parameter lists, R14 and R15
- Use the PSW, ILC and listings to locate a failing instruction in a dump
Lessons
- Why assembler still matters: registers and addressingAssembler is the human-readable form of the machine's own instructions. Most new code is not written in it, but exits, system code and older performance-critical modules are, and…
- Common instructions and linkage conventionsA small set of instructions does most of the work in real assembler code: load, store, move, compare, packed decimal arithmetic and branch.
- Storage definitions, dumps and program checksAssembler programs define their data with DC and DS, map other programs' storage with DSECTs and are packaged in CSECTs.
Track your progress and earn a certificate.
Free account, 15 quiz questions for this subject.