Address Compare Switch - IBM System/370 145 Operating Procedures Manual

ADDRESS COMPARE SWITCH
• This switch provides a match when the address used to
access main storage matches the address set in rotary
switches CDEFGH, and the STORAGE SELECT switch
is set to the MAIN STORAGE position .
• The action taken by the CPU as a result of the match
condition is determined by the ADDRESS COMPARE
CONTROL toggle switch.
C=-==:J
Gg
0:,
Q.
8
~0~o30~~~~~OOO~O ~~oo6o~~~oooooo~~
~~~~O~~506~ ~~~~00506666P666
B BG
B
50000
G
ADDRE~::MPARE ~
Operator Use
ANY (REAL ADR)
This position is for normal program processing. With the,
switch in this position, a match occurs for main storage
access when the storage address matches the address set
in rotary switches CDEFGH.
Note: To guarantee a match on instruction addresses,
the I-COUNTER positions must be used.
DATA STOR
This position allows a match when the storage address
matches the address set in rotary switches CDEFGH
during a data store operation.
I/O (Input/Output)
This position allows a match when the storage address
matches the address set in rotary switches CDEFGH, and
the operation is storing or fetching data for an I/O
operation.
I-COUNTER (REAL or LOGICAL ADR)
These positions allow a match when the real or logical main
storage address matches the address in rotary switches
CDEFGH, and the operation is an instruction fetch from
main storage.
I
Note: Significant throughput degradation can occur while
processing with this switch set to the I-COUNTER REAL ADR
position, and the ADDRESS COMPARE CONTROL switch
in the STOP or HARD STOP position.
DATA COMPARE TRAP
This position determines which instruction is causing a par-
ticu lar storage byte location to be modified. See "Data
Compare Trap," page 59.
ANY (LOGICAL ADR)
This position allows a match when the logical main storage
address used to access storage matches the address set in
rotary switches CDEFGH.
Note: To guarantee a match on instruction addresses,
the I-COUNTER positions must be used.
Service Use
The switch positions not defined are for service personnel
and are described in maintenance documentation.
System Control Panel Indicators, Switches, and Keys 15