All
Bit positioIiS 8-15 of the instruction are ignored.
The content of the Bl field designates a register. The
sum obtained by the addition of the content of reg
ister Bl and content of the Dl field identifies the
channel and the
Bit positions
positions
of the address, are ignored. Bit positions 21-23 of the
sum contain the channel address, while bit positions
24-31 identify the device on the channel and, on the
multiplexor channel, the subchannel.
all
they are encountered in the problem state, and that
all
NAME
Test
Halt
Test Channel TCH
M Privileged-operation exception
Programming Note
The instructions START
tents of the csw stored by the instruction from being
destroyed by an immediately following
tion, all channels must be masked before issuing
masked until the information in the csw provided by
the instruction has been acted upon or stored else
where for later use.
92
A write, read, read backward, control or sense opera
tion is initiated at the addressed
channel. The instruction
when the
Bit positions 21-31 of the sum formed by the addi
tion of the content of register Bl and the content of
the Dl field identify the channel, sub channel, and
location 72 contains the protection key for the sub
channel and the address of the first ccw. The ccw so
designated specifies the operation to be performed,
the main-storage area to be used, and the action to
be taken when the operation is completed.
The
if the addressed
able, the channel is available or is in the interruption
pending state, and errors or exceptional conditions
have not been detected. When the addressed part of
the
nel or device detect any error or exceptional condition
during exccution of the instruction, the
is not initiated.
When any of the following conditions occurs,
the csw at location 64 to be replaced by a new set of
status bits. The status bits pertain to the device
1. An immediate operation was executed, and no
command chaining is taking place. An operation is
called immediate when the
channel-end condition immediately on receipt
command code. The csw contains the channel-end bit
and any other indications provided by the channel or
the device. The busy bit is off. The
been initiated, but no information has been transferred
to or from the storage area designated by the ccw. No
interruption conditions are generated at the device or
snbchannel, and the sub channel is available for a
new
2. The
condition due to device end or attention, or the con-