Input I O,'tput Extended Logout Control (lL): Bit 2
ofcontrOiI register 14, when one, permits channel
logout into the110 extended logout area as part of
an110 interruption. When the 110 extended logout
mask is zero,1/0 extended logouts cannot occur.
This bit is initialized to zero.
Asynchronous Machine-Check Extended Logout
Control (AL): Bit 8 of control register 14, in con
junction withPSW bit 13, controls asynchronous
change of the machine-check extended logout area.
When this bit andPSW bit 13 are both ones, the
machine may change the machine-check extended
logout area at any time. This bit is initialized to zero.
Asynchronous Fixed Logout Control (FL): Bit 9 of
control register 14, when one, permits the fixed log
out area to be changed at any time. When this bit is
zero, the fixed logout area may be changed only
during a machine-check interruption or during an110 interruption. This bit is initialized to zero.
Programming Notes
The maximum logout information is obtained by
setting both the synchronous and asynchronous
machine-check extended logout control bits to ones.
Both of these bits must be zeros to prevent any
changes to the machine-check extended logout area.
When asynchronous machine-check extended logout
is allowed, use of the machine-check extended log
out area may produce unpredictable results.
When the asynchronous fixed logout control bit is
one, program use of the fixed logout area should be
restricted to the fetching of data from this are,a.
Store operations or channel programs reading into
the fixed logout area may cause machine checks or
undetected errors if the store occurs duringCPU retry. Note that this is an exception to the rule
that programming errors do not cause machine
check indications.
Machine··Check Subclass Masks
Bits 4-7 of control register 14, in conjunction withPSW bit 13, control various machine-check subclass
conditions. WhenPSW bit 13 is one and the subclass
mask isOIne, the associated condition initiates a
machine-,check interruption. If the subclass mask is
zero, the associated condition does not initiate an
182 System/370Principles of Operation
interruption, but the condition may be presented
with another condition which initiates the interrup
tion. All conditions presented are then cleared.Recovery Report Mask (RM): Bit 4 of control reg
ister 14 controls recovery-interruption conditions.
This bit is initialized to zero.
Degradation Report Mask (DM): Bit 5 of control
register 14 controls degradation-interruption condi
tions. This bit is initialized to zero.
External Damage Report Mask (EM): Bit 6 of con
trol register 14 controls the following machine-check
interruption conditions: timer damage, timing facility
damage, and external damage. This bit is initialized
to one.
Warning Mask (WM): Bit 7 of control register 14
controls all warning conditions. This bit is initialized
to zero.
Control Register 15
o 8
Machine-Check Extended Logout
Address
29 31
Bits 8-28 of control register 15, with three low-order
zeros appended, specify the starting location of the
machine-check extended logout area. The contents
of control register 15 are initialized by setting bit 22
to one andali other bits to zeros, which specifies a
starting address of 512 (decimal). The machine
check extended logout address is a real address.
When a model provides machine-check extended
logout, control register 15 is implemented.
Programming Note
The availability and extent of the machine-check
extended logout area differs among models and, for
any particular model, may depend on the features or
engineering changes installed. In order to provide for
such variations, the program should determine the
extent of the logout by means ofSTORE CPU ID
whenever a storage area for the extended logout is to
be assigned. A length of zero in the MCEL field
indicates that no MCEL is provided.
of
logout into the
an
mask is zero,
This bit is initialized to zero.
Asynchronous Machine-Check Extended Logout
Control (AL): Bit 8 of control register 14, in con
junction with
change of the machine-check extended logout area.
When this bit and
machine may change the machine-check extended
logout area at any time. This bit is initialized to zero.
Asynchronous Fixed Logout Control (FL): Bit 9 of
control register 14, when one, permits the fixed log
out area to be changed at any time. When this bit is
zero, the fixed logout area may be changed only
during a machine-check interruption or during an
Programming Notes
The maximum logout information is obtained by
setting both the synchronous and asynchronous
machine-check extended logout control bits to ones.
Both of these bits must be zeros to prevent any
changes to the machine-check extended logout area.
When asynchronous machine-check extended logout
is allowed, use of the machine-check extended log
out area may produce unpredictable results.
When the asynchronous fixed logout control bit is
one, program use of the fixed logout area should be
restricted to the fetching of data from this are,a.
Store operations or channel programs reading into
the fixed logout area may cause machine checks or
undetected errors if the store occurs during
that programming errors do not cause machine
check indications.
Machine··Check Subclass Masks
Bits 4-7 of control register 14, in conjunction with
conditions. When
mask is
machine-,check interruption. If the subclass mask is
zero, the associated condition does not initiate an
182 System/370
interruption, but the condition may be presented
with another condition which initiates the interrup
tion. All conditions presented are then cleared.
ister 14 controls recovery-interruption conditions.
This bit is initialized to zero.
Degradation Report Mask (DM): Bit 5 of control
register 14 controls degradation-interruption condi
tions. This bit is initialized to zero.
External Damage Report Mask (EM): Bit 6 of con
trol register 14 controls the following machine-check
interruption conditions: timer damage, timing facility
damage, and external damage. This bit is initialized
to one.
Warning Mask (WM): Bit 7 of control register 14
controls all warning conditions. This bit is initialized
to zero.
Control Register 15
o 8
Machine-Check Extended Logout
Address
29 31
Bits 8-28 of control register 15, with three low-order
zeros appended, specify the starting location of the
machine-check extended logout area. The contents
of control register 15 are initialized by setting bit 22
to one and
starting address of 512 (decimal). The machine
check extended logout address is a real address.
When a model provides machine-check extended
logout, control register 15 is implemented.
Programming Note
The availability and extent of the machine-check
extended logout area differs among models and, for
any particular model, may depend on the features or
engineering changes installed. In order to provide for
such variations, the program should determine the
extent of the logout by means of
whenever a storage area for the extended logout is to
be assigned. A length of zero in the MCEL field
indicates that no MCEL is provided.