AR mode programs returning control and using the linkage stack

To return control to the calling program after having saved registers on the linkage stack,, an AR mode program would:

• Place return information (if any) for the caller into AR/GPR 0, AR/GPR 1, or both. For information about passing information through a parameter list, see Conventions for passing information through a parameter list.
• Load the return code, if any, into GPR 15.
• Issue the PR instruction. The PR instruction restores the caller's ARs 2-14 and 64-bit GPRs 2-14 and ASC mode from the linkage stack, removes the entry from the linkage stack, and returns control to the caller.