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Programming Interface Information:
This information is NOT
intended to be
used as Programming Interfaces of VM/ESA. It is to be used for diagnosis only. |
EASIT
Cross Reference (Contains links to field and bit definitions)
EASIT Prolog
Name : HCPEASIT
Description: External-Address-Space-Identification
Token
DSECT : EASIT
Function : This DSECT maps an e-ASIT, which is CP's external
identification of an address space, and a guest's
identification of a host address space.
Located by : Any task accepting an e-ASIT from a guest, or
providing one to a guest.
Created by : HCPSITIE when translating an i-ASIT into an e-ASIT.
Deleted by : Any task which no longer needs the representation.
Notes : An e-ASIT is an eight-byte token, doubleword aligned,
and serves as an external representation of an
address space. In external documentation, "ASIT" is
used to designate an e-ASIT. An e-ASIT is given to
guests to represent an address space, and is
guaranteed to be a system-wide unique token, and
unique for the life of the current system IPL. When
referring to the same address space, the same token
is given to different guests. A test for equality
can therefore be used to see if two e-ASITs represent
the same address space. Since an e-ASIT can also be
received from guests, it must also be "verifiable".
That is, CP must be able to reliably decide when a
supposed e-ASIT is a legal token designating an
existing address space.
EASIT Control Block Content
EASIT DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure EASIT External-Address-Space-Identifica tion space-identification token. 0000 0 Address 4 EASASTEO Bits 1-25 are the ASTE origin ..11 1111 EASASTOB X'8000003F' Mask used to check for invalid bits in EASASTEO field. Bits 0 and 26-32 are unused and will be zeros when generated by CP, and must be zeros when generated by a guest. 0004 4 Signed 4 EASSCRSN E-ASIT space creation sequence number. 00000008 EASLEN *-EASIT Length in bytes of an e-ASIT 00000001 EASSIZE (EASLEN+7)/8 Size in doublewords of an e-ASIT
EASIT Storage Layout
*** EASIT - External-Address-Space-Identification * * +---------------------------+---------------------------+ * 0 | EASASTEO | EASSCRSN | * +---------------------------+---------------------------+ * 8 * *** EASIT - External-Address-Space-Identification
EASIT Cross Reference
(contains links to field and bit definitions)Symbol Dspl Value -------------- ---- -----EASASTEO 0000
EASASTOB 0000 3F
EASLEN 0004 00000008
EASSCRSN 0004
EASSIZE 0004 00000001
Last updated on 3 Aug 1999 at 11:54:10 EDT.
Copyright IBM Corporation, 1990, 1999