z/VM: CP Commands and Utilities Reference - z/VM - IBM

STORE Guest Storage (ESA/390)
Usage Notes
1540 z/VM: CP Commands and Utilities Reference
specified address are used instead of the address itself. In this case, the 64 bits
at the specified address are used as the new address for the Store command.
The indirect address specified here (following INDEX and BASE) is determined
after BASE and INDEX are applied.
A maximum of 16 indirection characters can be specified.
data
is the data you want to place in storage. It takes on different meanings,
depending on the type of STORE you are performing (N, S, K, or U). See the
descriptions of each of these operands for the meaning of data.
1. An attempt to store at an address in a protected page, or to change the key at
an address in a protected page, results in an error message. A protected page
is a page of read-only storage.
2. The operands HOME, AREGareg., ALEThexword., and ALEThexword.ALraddr.
are valid only if the the virtual machine is an ESA virtual machine.
3. When you use the operand ALEThexword.ALraddr., the primary list bit in the
ALET is ignored.
4. The operands L, PRI, SECO, HOME, ASTEraddr., STDhexword., ASNasn.,
AREGareg., ALEThexword., and ALEThexword.ALraddr. use the access
register translation (ART), the ASN translation or the dynamic address
translation (DAT) processes. These contain special case translation processes
including the following:
v ALET 0 always indicates the current primary address space designated by
the STD in guest control register 1, regardless of the current contents of the
dispatchable-unit access list.
v ALET 1 always indicates the current secondary address space designated
by the STD in guest control register 7, regardless of the current contents of
the dispatchable-unit access list.
v Access register 0 is always treated as containing the ALET 0. The contents
of access register 0 are not used during ART processing.
v General register 0 is always treated as containing the value 0 when used as
the base or index register. The contents of GR 0 are never used.
5. The BASE operand is primarily intended for use in conjunction with the L
operand. It allows a user to modify the storage his virtual machine uses in one
less step than would otherwise be possible. Without the BASE operand, a user
may need to display the contents of a general register, then add the
displacement, and then enter the STORE command to modify storage his
program is using. With the use of access registers, the BASE option allows the
user to modify storage without needing to know whether his program is
currently in access register mode. This is done automatically for him by CP.
6. If you use the BASEnn and INDEXnn operands together, the specified hexloc
is used as a displacement from the address formed by the sum of the contents
of the two specified registers.
The values in the registers specified by the BASEnn and INDEXnn operands
are treated as 24-bit or 31-bit real addresses according to the addressing
mode (A) bit in the virtual machine’s PSW. That is, if the A bit is 1, the value is
a 31-bit address. If the A bit is 0, the value is a 24-bit address. Address
wrap-around is applied to the sum of the specified starting address and the
contents of the two specified registers.