IBM 4300 Manual page 167

The condition code indicates whether the page
was addressable (0) or connected (1) before.
Resulting Condition Code:
o
Page was addressable
1 Page was already connected
2
3
Program Exceptions:
Addressing (operand 2)
Page Transition
Privileged Operation
Specification
RESET REFERENCE BIT
18213 1
o
16
20 31
The reference bit in the storage key associated with
the storage page that is designated by the
second-operand address is set to zero.
Bits 8-20 of the second-operand address
designate the page. Bits 0-7 and 21-31 of the
address are ignored.
The reference to the storage key is not· subject to
a protection exception. The storage key can be
accessed regardless of the state of the addressed
page.
The values of the remaining bits of the storage
key, including the change bit, are not affected.
The condition code is set to reflect the state of
the reference and change bits before the reference
bit· is set to zero.
Resulting Condition Code:
o
Reference bit zero, change bit zero
1 Reference bit zero, change bit one
2 Reference bit one, change bit zero
3 Reference bit one, change bit one
Program Exceptions:
Addressing (operand 2)
Privileged Operation
RETRIEVE STATUS AND PAGE
R5P 01(81),02(82) [55]
~------~------~----~/--~--~-----I
,----_10_8_
1
---11_1_1 1_1_1_1
1_/....L1_8_1........L._~
1
82
~~
o
8 16
20 32
36 47
10-8 IBM 4300 Processors Principles of Operation
The saved machine status is retrieved and stored at
the first-operand location. The contents of the
saved page are retrieved and stored at the
second-operand location.
The saved machine status, as retrieved, consists
of 256 bytes reflecting the state of the machine at
the last time that the manual machine-save
operation' was performed. (See the figure
"Machine Status, Retrieval Format" in Chapter 4,
"Control," for the contents.) The saved page
consists of the contents at that time of page
o.
The
storage key, page bits, and frame index for the
saved page are contained in the machine status.
If the two operands overlap, the results are
unpredictable.
If the saved information is valid, condition code
o
is set. If the saved information is invalid, neither
storage operand is accessed, no access exceptions
are recognized, and condition code 3 is set.
The saved machine status and page remain
unchanged.
Resulting Condition Code:
o
Save information is valid
1
2
3 Save information is invalid
Program Exceptions:
Access (store, operand 1 and 2)
Privileged Operation
Programming Notes
1. The saved information may be found invalid if
a partially performed machine save was
canceled by resetting the
machine~
The saved
information is invalid if a clear reset has been
performed since the last machine save.
RETRIEVE STATUS AND PAGE will indicate
an invalid save until another machine save is
performed.
2. Two executions of RETRIEVE STATUS AND
P AGE will retrieve the same status and page
information, as long as the information has not
been made invalid by a reset and no machine
save has intervened.
SET CLOCK
[5]
1
8204
1
o
16
20
31