control when a logout may occuri it has
the following format:
I
/
1 2 8 9
Synchronous Machine-Check
Extended-Logout Control
Bit 1
controls the logout action during a
machine-check interruption.
bit is
logout area may be changed during the
interruptioni when this bit is zero, the
area may be changed only under control
of the asynchronous machine-check
extended-logout-control bit, bit 8 of
control register 14. Bit 1 of control
register 14 is initialized to one.
Input/Output Extended-Logout
zero,
Bit 2 of control register 14 is initial
ized to zero.
Asynchronous Machine-Check
Extended-Logout
conjunction with
asynchronous change of the machine-check
extended-logout area. When this bit and
may change the machine-check extended
logout area at any time; when this bit
is zero, the area may be changed only
under control of the synchronous
machine-check extended-logout-control
bit, bit 1 of control register 14. Bit
8 of control register 14 is initialized
to zero.
Asynchronous Fixed-Logout
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
ruption. Bit 9 of control register 14
is initialized to zero.
Control register 15 contains the
machine-check extended-logout address
and has the following format:
o 8 29 31
Bits 8-28 of control register
three rightmost zeros appended, desig
nate the starting real location of the
machine-check extended-logout
15 are initialized by setting bit 22 to
one and all other bits to zeros, which
specifies a starting address of 512
(decimal).
ing is installed, the
still a 24-bit real address and is
extended on the left with zeros. Thus,
the machine-check extended logout can
wrap from real location 224 -1 to real
location
extended logout
15 is implemented.
1. The availability and extent of the
machine-check
differs among models and, for any
particular model, may depend on the
facilities or engineering changes
installed. In order to provide for
such variations, the program should
determine the extent of the logout
by means of
storage area for the extended
logout is to be assigned. A length
of zero in the
results from executing
2. 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.
3. Use of the machine-check extended
logout area while asynchronous
machine-check extended logout is
allowed may produce unpredictable
results.
Chapter 11. Machine-Check Handling 11-29