Where more than one page-reference is given, major references
appear first.
absolute address 95, 14
absolute main storage 92
access control bits (in key in storage) 38
access exception 80 handling of (table) 81
priority of 83
recognition of 80 recognition of (table) 83
access to main storage, right of 38
accesses (references), sequence of main storage 23
active, state of address translation table entry 65
adapter, channel-to-channel 186
ADD (A, AR) instruction 117
ADD DECIMAL (AP) instruction 149
example 305 ADD HALFWORD (AH) instruction 117
example 291
ADD LOGICAL (AL, ALR) instruction 120 ADD NORMALIZED (ADR, AD, AER, AE) instruction 160 example 309 ADD NORMALIZED (AXR) instruction 160 ADD UNNORMALIZED (AWR, AW, AUR, AU) instruction 162
example 309 address
absolute 95, 14
base 21
branch 22
channel/device 192
failing-storage (see failing-storage address)
invalid 77
logical 14,58
of channel command word, in CSW 229
-real 95, 14, 57
translation (see dynamic address translation)
virtual 57
address arithmetic (generation) 21
address-compare controls 244
address generation 21
address identification, CPU 101 addresses
handling of 63
translated (see dynamic address translation)
types of 62
addressing
capability 14
information in a register 20 limitations of 14
main storage 14
wraparound 14
addressing exception 76,15
during address translation 61,62,81
summary table 77
. addressing, I/O channel 191
device 191
nonexistent or protected areas 213
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By TNL: GN22-0498
alert condition (machine-check interruption) 175
degradation 179
warning 179
alteration mask for program-event recording 40 alteration of an instruction by EXECUTE 129
AND (NR, N, NI, NC) instruction 120 example 292 Index arithmetic (see decimal instructions; floating-point-instructions;
general instructions)
assembly language, symbolic operand designations for System/370 (see individual instruction descriptions)
assigned main storage locations 90 absolute 91
real 90 asynchronous fixed logout (see machine-check fixed logout)
asynchronous fixed logout control bit (in control register 14) 182
asynchronous machine-check logout (see machine-check extended
logout and machine-check fixed logout)
asynchronous MCEL control bit (in controlregister 14) 182
attached, state of address translation table entry 65
attachment of I/O devices 186
attention (I/O unit status condition) 229,239
availability, System/ 370 facilities for achieving 11
available (I/O system state) 193
B field of an instruction 20,21 backed-up bit (machine-check interruption code) 179
base address (in operand designation) 21
basic-control mode 31 PSW format 33
(see also extended-control mode)
BC mode (see basic-control mode)
binary notation, excess-64 159
bit, check 14
bits in a byte 14
block-concurrent references to storage 27
block of data, I/O definition 210 self-describing 214
block-multiplexer channel 188
block-multiplexing-control bit 189
block-multiplexing mode bit (in control register 0) 189
blocking of data (I/O operations) 210 boundaries in main storage, integral 15
branch address 22
BRANCH AND LINK (BAL, BALR) instruction 121
example 292
BRANCH ON CONDITION (BC, BCR) instruction 121
example 292
BRANCH ON COUNT (BCT, BCTR) instruction 122
example 293
BRANCH ON INDEX HIGH (BXH) instruction 122
example 293
BRANCH ON INDEX LOW OR EQUAL (BXLE) instruction 123
example 293
branch, successful (program event) 42
branching, general description of 22
burst mode 187
bus out check (sense data) 220 Index 315

Page of GA22-7000-4
Revised September 1, 1975
By TNL: GN22-0498
busy (I/O unit status condition) 230, 238
byte (definition) 14
byte index field 58
byte-interleave mode 187
byte-multiplexer channel 188
byte-oriented-operand feature 15
cache 13
CAl (channel available interruption) 227
CAW (channel address word) 210,190
CBC (checking block code) 171
CBC, invalid
handling of
in keys in storage 173
in registers 173
in storage 172
CCW (channel command word) 189,211
address in CAW 210 address in CSW 229
command code 212
definition 211
CCWI (lPL) in absolute main storage 91
CCW2 (lPL) in absolute main storage 91
central processing unit (see CPU) chain command (CC) flag (in CCW) 211
chain data (CD) flag (in CCW) 211
chaining check (channel status condition) 235,237
chaining, command 215,279
chaining data 213,191
change bit 57,67 channel 187
address 192
burst mode 187
byte-interleave mode 187
commands 217
compatibility of operation 191
control check (status condition) 235,237
data check (status condition) 235,237
description of 17
equipment error 196
identification (lD) 240,206
indirect data addressing (CIDA) 216
mask, BC mode (see extended control mode) 33
masks (in control register 2) 88
modes of operation 187
not operational (state of I/O system) 194
program, termination of (or conclusion of) 222
sub channel 188 types 188
working (state of I/O system) 194
channel address validity flag 241
channel address word (CAW) 190,210
channel available interruption (CAl) 227
channel command word (see CCW)
channel end (I/O unit status condition) 231, 238 channcllD 240,92,206
channel logout 240 channel status conditions 233 chaining check 235
channel control check 235
channel data check 235
incorrect length 233
interface control check 235
program check 234
program-controlled interruption 233
protection check 234
316 System/370 Principles of Operation
channel status word (CSW) 228
channel-to-channel adapter 186
characteristic in floating-point operand 158
check (or checking) bit 171, 14
check-stop indication 245
control bit (in control register 14) 181
status bit 99
check-stop state 31
checking block 171
code (see CBC)
class number, monitor 39
classes of interruptions (see interruption classes)
CLEAR I/O (CLRIO) instruction 198
clock
interval timer as a real-time 49
time-of-day (TOD) 46
clock comparator 47
interruption 48, 87
interruption submask 88
mask bit (in control register 0) 87
priority of interruption 86
valid bit in machine-check interruption code 180 save area (machine-check extended interruption information,
timing facilities) (see timing facilities) 177
code
command 217
condition (see condition code in PSW) instruction length 71, 34, 72
interruption, in BC mode PSW 34, 72
monitor 39
operation 19
PER (program-event recording) 40 codes, decimal sign, and zone 148
command
control 219 I/O 210,217
read 218
read backward 218
retry 221
sense 219
transfer in channel 221
write 218
command address, I/O 236
in CAW 210 in CSW 229,235
command address/key validity flag 241
command chaining 215,191
command code (in CCW) 211
command, immediate (see immediate operation) 222
command reject (sense data) 220 command retry 221
communications area, I/O 239
COMPARE (C, CR) instruction 123
COMPARE (CDR, CD, CER, CE) instruction 163
example 310 COMPARE AND SWAP (CS) instruction 123
example 310 COMPARE DECIMAL (CP) instruction 149
example 305 COMPARE DOUBLE AND SWAP (CDS) instruction 124
COMPARE HALFWORD (CH) instruction 125
example 294
COMPARE LOGICAL CHARACTERS UNDER MASK (CLM)
instruction 126
example 295