Sensing - Control Data 3100 Reference Manual

SENSING
Rev. B
Operation
Address
77.2 EXS
x,ch;x~O
COpy
x,cn;x=O
77.4 INTS
77.3 INS
CINS
x,ch
x,ch;x~O
x,ch;x = 0
23 18 17 15 14 12 11 00
77 2
I
ch
I
x
ch = I/O channel designator, 0-3
x = external status sensing mask code
(see Comments below)
Interpretation
Sense external status
Copy external status
Sense interrupt
Sense internal status
Copy internal status
(Approximate execution time: 2.2 ,usee.)
Instruction Description: When a peripheral equipment controller is connected to an I/O
channel by the CON (77.0) instruction, the EXS instruction can sense conditions within
that controller. Twelve status lines run between each controller and its I/O channel. Each
line may monitor one condition within the controller, and each controller has a unique set
of line definitions. To sense a specific condition, a "I" is placed in the bit position of
the status sensing mask that corresponds to the line number. When this instruction is rec-
ognized in a program, RNI at address P
+
1 if an external status line is active when its
corresponding mask bits are "I". RNI at address P
+
2 if no selected line is active.
Comments: Refer to the 3000 Series Computer Systems Peripheral Equipment Codes man-
ual, publication no. 60113400 for a complete list of status response codes.
23 18 17 15 14 12 11 00
77
2
I
ch
I
0000
(Approximate execution time: 2.2 ,usee.)
ch
=
I/O channel designator, 0-3
Instruction Description: This instruction performs the following functions:
1.
The external status code from I/O channel ch is loaded into the lower 12 bits of A. See
EXS instruction.
2.
The contents of the Interrupt Mask register are loaded into the upper 12 bits of A. See
Table 7-4.
3.
RNI from address P
+
1.
7-60