HLASM - SSK = Set Storage Key
The opcode of the SSK instruction is X'08'.
- Set the storage key of a page of real storage.
- Register holding a storage key.
- Register containing a page address.
- The processor sets the storage key of the 2K or 4K page addressed by the
second argument. It is set to the value specified in the low-order byte of
the first argument.
- The condition code does not change.
- If the page address is not a fullword address the instruction fails.
The page address does not have to be on a page-boundary, however; any
fullword address within a page addresses the page in its entirety.
- ISK was intended to obtain storage keys.
- SSKE is now used to set the storage key of a
page of real storage.
- The SSK instruction was part of the original S/360 instruction set.
However, it is no longer supported; it has been replaced by the
SSKE instruction. Support for the ISK instruction
has been dropped when the 370/XA architecture was introduced.
- Independent of Amode or DAT, the page address is always a 24-bit real
- The storage key was taken from the low-order 8 bits of the 32-bit
register specified as the second argument in the following format:
- The first 4 bits (0 through 3) were the actual storage key.
- If fetch protect was installed (an optional feature on early machines),
the fetch-protect bit was taken from bit 4.
- If DAT was installed the Change and Reference bits were taken from bits
5 and 6. I don't know in which order.
- Initially the SSK instruction worked on 2K pages only. When 4K pages were
introduced, the SSK instruction was modified to address either a 2K page or
a 4K page, depending on the address specified and the way that specific page
Not available (yet).
To the Opcodes Overview.
To the English Homepage for Hlasm.com.
To the General Homepage for Bixoft and Hlasm.com.
This site is a member of WebRing.
You are invited to browse the
list of mainframe-loving sites.
Dinos are not dead. They are alive and well and living in data centers all
around you. They speak in tongues and work strange magics with computers.
Beware the dino! And just in case you're waiting for the final demise of
these dino's: remember that dinos ruled the world for 155-million years!
Dinos and other anachronisms
[ Join Now
| Ring Hub
Below you find the logo of our
and logos of the web-standards that this page adheres to.