The following comment applies to all user-written programs mentioned in Part 6 of this book:
Upon return from any customer-written program, CICS® must always receive control in primary-space
translation mode, with the original contents of all access registers restored,
and with all general purpose registers restored (except for those which provide
return codes or linkage information).
For information about translation
modes, refer to the IBM® ESA/370 Principles of Operation manual.