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CLEAR PAGE
[5]
'B215'
o
16
20
31
The storage page designated by the second-operand
address is cleared, which is equivalent to storing
2,048 zero bytes at that location. The page is
validated. .
Bits 8-20 of the second-operand address
designate the page. Bits 0-7 and 21-31 of the
address are ignored.
The page may be addressable or connected; if
the page is disconnected, a page-state exception is
raised, and the operation is suppressed.
Condition Code: The code remains unchanged.
Program Exceptions:
Addressing (operand 2)
Page State
Privileged Operation
Protection (store, operand 2)
Programming Note
Page 0 may be cleared, but it can only be in the
addressable state.
CONNECT PAGE
o
8
12
16
20
31
If
disconnected, the storage page designated by the
second-operand address enters the connected state.
If
already connected, the page remains in the
connected state. The frame index of the page
frame that is connected to the page is returned in
the general register designated by the R
1
field.
Bits 8-20 of the second-operand address
designate the page. Bits 0-7 and 21-31 of the
address are ignored. Bits 12-15 of the instruction
are ignored.
If
bits 8-20 of the second-operand address are
zeros, that is, page 0 is specified, a specification
exception is recognized, and the operation is
suppressed.
If
the page is in the addressable state, a
page-transition exception is recognized, and the
operation is suppressed.
If
the operation is not successful, because the
page is disconnected but no page frame is free for
connection (free-frame-capacity count is zero), the
R
1
register remains unchanged, and condition code
2
is set.
If
the operation is successful, the condition code
indicates whether the page was connected (1) or
disconnected (0) at the start of the operation. The
frame index, which is an unsigned binary integer, is
loaded right-aligned in the Rl register, and the
remaining high-order bits of the register are set to
zeros. The frame index is unique and may have
any value from zero to EPCC - 1, where EPCC is
the existing-frame-capacity count.
If
the page was disconnected before and the
operation is successful, the value of the free-
frame-capacity count is decreased by one.
The contents of a newly connected page frame
are unpredictable.
Resulting Condition Code:
o
Successful, page was disconnected, index
returned
1
2
3
Page was already connected, index returned
Not successful, index not returned
Program Exceptions:
Addressing (operand 2)
Page Transition
Privileged Operation
Specification
Programming Notes
1. The storage key and the reference, change, and
page bits of a page are not changed when the
page is connected.
2. The frame index of the page frame connected
to the specified page remains unchanged until
that page is disconnected. The value of the
frame index to be assigned by CONNECT
P AGE to a previously disconnected page is
unpredictable.
DECONFIGURE PAGE
'B21B'
o
16
20
31
Chapter 10. Control Instructions
10-3
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