Registers have the following contents when control returns to the
caller of the callable service.
- R0
- Not defined by Language Environment
- R1
- Not defined by Language Environment
- R2–R11
- Preserved
- R12
- Points to the CAA
- R13
- Points to the caller's DSA
- R14
- Not preserved
- R15
- Not preserved
Note: - The called procedure must ensure that R2 through R13 have the
same values on exit as they had on entry.
- The called procedure cannot rely upon the values contained in
R0, R1, R14, and R15 unless explicitly stated by the interface.