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.