Establishing addressability to the text unit pointer list

One way to establish addressability to the text unit pointer list is to find the address at the end of the request block (by adding S99RB and S99RBLEN) and base S99TUPL at this address.

You might want to set up your SVC 99 parameter list differently. For example, you might want the request block extension to follow the request block, instead of the text unit pointer list. You can do so as long as your pointers are correct.