control registers 1, 5, and 7. When the
steps are not successful, no control
registers are changed, and the reason is
indicated in the condition code.
The doubleword first operand contains a
PSW-key mask (PKM), a secondary ASH (SASH), an authorization index (AX), and
a primary ASH (PASH). The primary ASH is translated by means of the ASH­ translation tables to obtain a PSTD,
LTD, and, optionally, an AX. The
secondary ASH is translated by means of
the ASH-translation tables to obtain an
SSTD, and, optionally, an authority
check is made to ensure that the new AX
is authorized to establish the new SASH. The doubleword at the first-operand
location has the following format:
PKM-d SASH-d AX-d PASN-d
o 16 32 48 63 The "d" stands for designated doubleword
and is used to distinguish these fields
from other fields with similar names
which are referred to in the definition.
The current contents of the correspond­
ing fields in the control registers are
referred to as PKM-old, SASH-old, etc.
The updated contents of the control
registers are referred to as PKM-new,
SASH-new, etc.
The second-operand address is not used
to address data; instead, the rightmost
three bits are used to control portions
of the operation. The remainder of the
second-operand address is ignored. Bits
29-31 of the second-operand address are
used as follows:
Function Specified
in Second Operand
Bit When Bit I s Zero When Bit Is One
29 ASH translation ASH translation
performed only performed.*
when new ASH and
old ASH are dif-
ferent. 30 Use AX associ-Use AX from
ated with PASH. first operand. 31 SASH authoriza- SASH authoriza-
tion performed.* tion not per-
formed. * SASH translation and SASH authori-
zation are performed only when SASH-d is not equal to PASH-d.
When SASN-d is equal to PASH-d, the SSTD is loaded from the PSTD,
and no authorization is performed.
The operation
PARAMETERS is
of LOAD ADDRESS
depicted in the SPACE figure
"Execution of LOAD ADDRESS SPACE PARAME­ TERS." PASH Translation
In the PASH translation process, the
PASH-d is translated by means of the ASH first table and the ASH second table.
The STD and LTD fields and, optionally,
the AX field, obtained from the ASH­ second-table entry are subsequently used
to update the corresponding control
registers.
When bit 29 of the second-operand
address is one, PASH translation is
always performed. When bit 29 is zero, PASH translation is performed only when
PASH-d is not equal to PASH-old. When
bit 29 is zero and PASH-d is equal to
PASH-old, the PSTD-old and LTD-old are
left unchanged in the control registers
and become the PSTD-new and LTD-new,
respectively. In this case, if bit 30 i s zero, then the AX-o 1 dis left
unchanged in the control register and
becomes the AX-new.
The PASN translation follows the normal
rules for ASH translation, except that
the invalid bits, bit 0 in the ASH­ first-table entry and bit 0 in the ASH­ second-table entry, when ones, do not
result in an ASH-translation exception,
and the space-switch-event-control bit
in the ASH-second-table entry, when one,
does not result in a space-switch event.
When either of the invalid bits is one,
condition code 1 is set. When the ASH­ second-table entry is valid and either
the current space-switch-event-control
bit in control register 1 is one or the
space-switch-event-control bit in the
ASH-second-table entry is one, condition
code 3 is set. When condition code 1 or
3 is set, the control registers remain
unchanged.
The contents of the AX, STD, and LTD
fields in the ASH-second-table entry
which is accessed as a result of the PASH translation are referred to as
AX-p, STD-p, and LTD-p, respectively.
SASH Translation
In the SASH-translation process, the SASH-d is translated by means of the ASH first table and the ASH second table.
The STD field obtained from the ASH­
second-table entry is subsequently used
to update the secondary-segment-table
designation (S5TD) in control register
7. The ATO and ATL fields obtained are
used in the SASH authorization, if it
occurs. Chapter 10. Control Instructions 10-13

SASH translation is performed only when SASH-d is not equal to PASH-d. When
SASH-d is equal to PASN-d, the SSTD-new is set to the same value as PSTD-new. When SASH-d is equal to SASH-old, bit 29
(force ASH translation) is zero, and bit 31 (skip SASH authorization) is one,
then SASH translation is not performed,
and SSTD-old becomes SSTD-new.
The SASH translation follows the normal
rules for ASH translation, except that
the invalid bits, bit 0 in the ASH­ first-table entry and bit 0 in the ASH­ second-table entry, when ones, do not
result in an ASH-translation exception.
When either or both of the invalid bits
are ones, condition code 2 is set, and
the control registers remain unchanged.
The contents of the STD, ATO, and ATl
fields in the ASH-second-table entry
which is accessed as a result of the SASH translation are referred to as
STD-s, ATO-s, and ATl-s, respectively. SASH Authorization SASH authorization is performed when bit
31 of the second-operand address is zero
and SASH-d is not equal to PASH-d. When SASH-d is equal to PASH-d or when bit 31 of the second-operand address is one, SASH authorization is not performed. SASH authorization is performed by using ATO-s, ATl-s, and the intended value for
AX-new. When bit 30 of the second­
operand address is zero and PASH trans­
lation was performed, the intended value
for AX-new is AX-p. When bit 30 of that
address is zero and PASH translation was
not performed, the AX is not changed,
and AX-new is the same as AX-old. When
bit 30 of that address is one, the
intended value for AX-new is AX-d. SASH authorization follows the rules for
secondary authorization as described in the section "ASH-Authorization Process" in Chapter 3, "Storage." If the SASH is
not authorized (that is, the authority­
table length is exceeded, or the
selected bit is zero), condition code 2
is set, and none of the control regis­
ters are updated.
Control-Register loading
When the PASH-translation, SASH­ translation, and SASH-authorization
functions, if called for in the opera­
tion, are performed without encountering
any exceptions, the operation is
completed by replacing the contents of
control registers 1, 3, 4, 5, and 7 with
the new values, and condition code 0 is
set. The control registers are loaded
as follows: 10-14 System/370 Principles of Operation The PSW-key-mask and SASH fields in
control register 3 are replaced by the
PKM-d and SASH-d fields from the first­
operand location.
The PASH, bits 16-31 of control register
4, is replaced by the PASH-d field from
the first-operand location.
The authorization index, bits 0-15 replaced
of
as control register 4, is follows: • When bit 30 of the second-operand
address is one, from AX-d. • When bit 30 of the second-operand
address is zero and PASH trans­
lation is performed, from AX-p. • When bit 30 of the second-operand
address is zero and PASH trans­
lation is not performed, the
authorization index is not changed.
The primary-segment-table designation in
control register 1 and the linkage-table
designation in control register 5 are
replaced as follows: • When PASH translation is performed,
the primary-segment-table designa­
tion in control register 1 and the
linkage-table designation in
control register 5 are replaced
from the STD-p and lTD-p fields,
respectively, which are obtained
during PASH translation. • When PASH translation is not
performed, the primary-segment­
table-designation and linkage­
table-designation fields remain
unchanged.
The contents of the secondary-segment­
table designation in control register 7 are replaced as follows: • When SASH-d equals PASH-d, by the
new contents of control register 1,
the primary-segment-table desig­
nation. • When SASH translation is performed,
by the contents of the STD-s.
When SASH-d does not equal PASH-d and SASH translation is not performed, the
secondary-segment-table designation re­
mains unchanged.
other Condition-Code Settings
When PASH translation is called for and
cannot be completed because bit 0 is one
in either the ASH-first-table or the
ASH-second-table entries, condition code
1 is set, and the control registers are
not changed.