Xerox 560 Reference Manual page 143

If CC4
=
0, the MIOP is in a normal mode of operation and
the meaning of the condition code during a no is:
2 3 4 Meaning
0 0 0
o
0
o
0
o
o
o
I/O address recognized, acceptable SIO is
currently possible, and status information in
general registers is correct.
o
For RMP, I/O address recognized, acceptable
SIO is currently possible; however, status
information in the general registers may be
incorrect. For MIOP, not possible.
o
I/o address recognized but acceptable SIO
is not currently possible because device con-
troller or device is busy. Status information
in general registers is correct.
o
For RMP, I/O address recognized but accept-
able SIO is not currently possible because
device controller or device is busy; status
information in general registers may be in-
correct. For MIOP, not possible.
o
Processor Interface detected parity error on
returned status and/or condition code. The
result of the no is indeterminate.
o
0 I/O address not recognized, no not ac-
cepted, and status information returned to
general registers is incorrect .
o ..... 1_ T
Ir.
_...1...1 __________ : __ ...1 __ ...I TTr.
_L... __
~_.J
. ' v
1./ '-'
\,oiu ......
C;~ • C,"",~III~vU
..... I.U .... '"" ....
..,va ."""'"
because an error detected when the lOP at-
tempted to read and transfer the no param-
eters (device/device controller address and
R field information) from the BP to the lOP via
main memory. Status information returned to
general registers is incorrect.
If CC4
=
1, the MIOP is in the test mode and the meaning
of the condition code during a no is:
2 3 4 Meaning
0 0 0
o
0
o
0
o
o
Unit is performing an Order Out operation.
Unit is performing an Order In operation.
Unit is performing a Data Out operation.
Parity error detected by Processor Interface
on returned status and/or condition code.
The result of the no is indeterminate.
Unit is performing a Data In operation.
BCF detected while unit performing a Data
In operati on.
TDV
TEST DEVICE
(Word index alignment, privileged)
TEST DEVICE is used to provide information about a device
other than that obtainable by means of the no instruction.
The operation of the selected lOP, device controller, and
device is not affected, and no operations are initiated or
terminated. The responses to TDV provide the program with
information giving details on the condition of the selected
device, the number of bytes remaining to be transmitted in
the current operation, and the present point at which the
lOP is operating in the command list.
If the R field of the TDV instruction is 0, the condition
code is set, but no general registers are affected.
If the R field of TDV is an odd value, the condition code
is set and the device status and byte count are loaded into
register R as follows:
If the value of the R field of TDV is an even value and
not 0, the condition code is set, register Ru1 is loaded as
shown above, and register R is loaded as follows:
D_C __
~_ ~L...
__
~_I:
__
L...I~ ~""r:_L...""r_1
r""&",,ro ... _o .... ,.. ..... ,..1
&,..r
" " ' ' ' ' ' v " ' "
"'"t't""""'"~'" t"'" 't""""~' ''', .... "" ... " .. ,-,,--, ''''
description of Device Status Byte. Refer to Tables 16 and 17
for functions of other bits within status words.
Affected: (R), (Ru 1), CC
If CC4
=
0, the MIOP is in a normal mode of operation and
the meaning of the condition code during a TDV is:
2 3 4 Meaning
o
0 0 0 I/O address recognized, no device-dependent
condition present, and status information in
general registers is correct.
o
0
o
o
o
For RMP, I/O address recognized and no
device-dependent condition present; however,
status information in general registers may be
incorrect. For MIOP, not possible.
o
0 I/O address recognized and device-dependent
condition is present or device controller is in
test mode.
o
For RMP, I/o address recognized, device-
dependent condition is present, or device con-
troller is in test mode; but status information
in the general registers may be incorrect. For
MIOP, not possible.
Input/Output Instructions 137