(Old thread, just got back) The savearea provided to the ETXR is 72 bytes long. A CAUTION. In many cases it is not safe (system intergrity wise) to use the savearea pointed to by R13 if you are running in a space that could have user tasks (not yours) running. For example, consider a vanilla key 8 address space, where you have at some point switched to key 0 and done an ATTACH with ETXR for the attached routine to get control in key 0. In this case, the R13 savearea is in key 8.
>I did some testing and more reading and discovered the following... >a) The Extended Addressability Guide says that each workunit (TCB or SRB) >has its own stack. From that I it appears that the IRB is sharing the stack >with the orginating task. So, I won't be using the stack to save the state in >the exit. Hence the second question on the size of the save area provided by >the system for the exit. As Binyamin asked, Why can't you use the stack? You are using the same stack, but you would not be overwriting existing entries if you use it, you would be creating new ones. As a result of the CAUTION case that I mentioned above, we almost always use the linkage stack for ETXR reg saving. >b) I checked the contents of 4(r13) and 0(r14) upon entry to the ETXR. 4 >(r13) does not contain F6SA, so I assume it's a standard 72 byte save area; >and r14 does point to an SVC 3. This is not a good assumption, though the conclusion is true. The presence of information such as F6SA at offset 4 says little about the length or format of *this* area. It is primarily a statement about how registers were saved (or not saved) in the previous area. Since there is no previous area, no data is provided. If you were to provide your own, chained, savearea, you would put into it how you saved the registers in the system-provided area (such as by putting the 'previous pointer' or F1SA if you used the linkage stack). Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
