DIAGNOSE Code X'10' – Release Pages
Privilege Class: Any
Addressing Mode: 24-bit, 31-bit, or 64-bit
Use DIAGNOSE code X'10' to release pages of second-level storage.
Entry Values:
- Rx
- Contains the guest real address of the first page of storage to be released. This address must be on a page boundary, otherwise a specification exception occurs.
- Ax
- For XC virtual machines in the access-register mode, Ax contains the ALET designating the address space in which storage is to be released. Even when Rx is general register 0, the actual contents of Ax are used in XC access-register mode.
- Ry
- Contains the guest real address of the last page to be released. This address must be on a page boundary, and must be greater than or equal to the address specified in the Rx register; otherwise, a specification exception occurs.
The results of the DIAGNOSE X'10' operation on a particular
page depend on whether the page is a mapped or unmapped page, and
for unmapped pages, whether the page is contained in a saved segment
or not. A page is considered mapped when the DEFINE function of the
MAPMDISK macro has been used to associate the page with a DASD block
on a minidisk; otherwise, it is an unmapped page. If the page is:
- An unmapped page that is not contained in a saved segment, then the page is unlocked (if it was locked through the LOCK command), the current contents of the page are discarded and the page is considered to contain binary zeros.
- An unmapped page that is contained in a saved segment, then no operation is performed. The page remains unchanged.
- Is a mapped page, then the page is unlocked (if it was locked through the LOCK command), the current contents of the page are discarded, and upon next reference the contents of the page are refreshed from the associated DASD block.
The range of storage between the addresses specified in the Rx and Ry registers must be contained entirely within the defined storage for the address space. That is, this DIAGNOSE code cannot be used to release discontiguous storage. If an attempt is made to release discontiguous storage, an addressing exception is recognized.
For an XC virtual machine in the access-register mode, a specification exception is recognized if an attempt is made to release storage in a host-primary address space through a nonzero ALET.