SHIFT RIGHT SINGLE (SRA) instruction 140 SHIFT RIGHT SINGLE LOGICAL (SRL) instruction 141
short block (in I/O) 233
short floating-point number 158 SI instruction format 20 sign and zone codes in decimal operands 147, 148
sign change in fixed-point operations 116
SIGNAL PROCESSOR (SIGP) instruction 110 signaling and response, CPU 97
orders 97
status bits 99
significance
exception 79
indicator in editing 151
simultaneous interruption requests, multiple (see priority of
interruptions) 89
skip (SKIP) flag (in CCW) 211
skipping (in I/O) 215 SLI (suppress-length-indication) flag in CCW 211
source digit in editing 150 source field (in limited channel logout) 240 source identification of interruptions 70 special operation exception 80 specification exception 77 SS instruction format 20 SSM suppression bit (in control register 0) 32 START I/O (SIO) instruction 204 START I/O FAST RELEASE (SIOF) instruction 204 start key 247
start order 97
states
check-stop 31 CPU 30 load 31
of I/O system 192
of time-of-day clock 46
operating 30 problem 30 program (see CPU states)
running 30 stopped 30 supervisor 30 wait 30 status
bits (signal processor) 99
conditions, I/O 229,237
in CSW 229, 237
modifier (I/O unit status condition) 229
of system (from wait, manual, and system indicators) 248
word, program (PSW) 32
stop-and-store-status order 98
stop key 247
stop order 97
stopped
state 30 status bit 99
storage
address wraparound 14
addressing, logical 58
alteration program event 42
control unit (SCU) identity (in limited channel logout) 240 key 38
logical validity (machine-check interruption code) 181
main (see main storage)
operand 20 Page of GA22-7000-4
Revised September 1, 1975
By TNL: GN22-0498
storage (con tinued)
operand reference (access) 25
validation 173
storage error
corrected bit (machine-check interruption code)
uncorrected bit (machine-check interruption code)
storage protection 38
accesses protected 39
action 38
fetch 38
key in storage 38
violation (see protection exception) STORE CPU ADDRESS (STAP) instruction 112 STORE PREFIX (STPX) instruction 113
store-status
facility 54
key 247
save area in absolute main storage 91 STORE (ST) instruction 141 STORE (STD, STE) instruction 168 STORE CHANNEL ID (STIDC) instruction 206 STORE CHARACTER (STC) instruction 141 180 180 STORE CHARACTERS UNDER MASK (STCM) instruction 141 STORE CLOCK (STCK) instruction 141 STORE CLOCK COMPARATOR (STCKC) instruction 111 STORE CONTROL (STCTL) instruction 111 STORE CPU ID (STIDP) instruction 112 STORE CPU TIMER (STPT) instruction 113 STORE HALFWORD (STH) instruction 142 STORE MULTIPLE (STM) instruction 142
example 302 store protection (see storage protection) 38
store reference, storage operand 25
store status 54 STORE THEN AND SYSTEM MASK (STNSM) instruction 113 STORE THEN OR SYSTEM MASK (STOSM) instruction 114
sub channel 188
non shared 189
not operational (I/O system state) 194
shared 189
working (I/O system state) 194
submask, external interruption 86 SUBTRACT (SR, S) instruction 143 SUBTRACT DECIMAL (SP) instruction 154 SUBTRACT HALFWORD (SH) instruction 143 SUBTRACT LOGICAL (SLR, SL) instruction 143 SUBTRACT NORMALIZED (SER, SE, SDR, SO) instruction 169 SUBTRACT NORMALIZED (SXR) instruction 169 SUBTRACT UNNORMALIZED (SWR, SW, SUR, SU) instruction 169
successful branching program event 42
supervisor-call interruption 84
supervisor-call interruption identification in main storage 90 SUPERVISOR CALL (SVC) instruction 144
supervisor program (see system program) 10 supervisor state 30 suppress-length-indication (SLI) flag in CCW 211
suppression, method of ending instruction execution 74
synchronization of TOD clock 101,47
synchronous machine check logout (see machine-check extended
logout and machine-check fixed logout)
synchronous MCEL control bit (in control register 14) 181
system
clear reset 53
console 243, 18
control 29
Index 325

system (continued)
control instructions 103 damage (machine-check interruption condition) 178
indicator 247
operation, I/O 189
organization 13
program 10 recovery (machine-check interruption condition) 178, 175
reset, I/O 194,51
system control panel (of the system console)
customer-engineer-control section 248
operator-control section 243
system indication 247
system-reset key 247
system status (from wait, manual, and system indicators) 248
table
manipulation 64
page 60 segment 59
translation 60 termination method of ending instruction execution 74
of channel program 222
of I/O operations (see conclusion of I/O operations) TEST AND SET (TS) instruction 144 TEST CHANNEL (TCH) instruction 207 test indicator 247 TEST I/O (TIO) instruction 208 TEST UNDER MASK (TM) instruction 145
example 303 thermal/CB power check indication 247
TIC (transfer in channel) I/O command 221
time-of-day (TOD) clock 46 key 247
power-on reset 53
states of 46
sync-check external interruption 87
sync control bit 47
synchronization of 101,47 timeout, channel 188
timer, CPU 48
timer damage (machine-check interruption condition) 179,175
timer, interval 49
external interruption 86
updating 49
timing facilities (see CPU timer, clock comparator, interval timer,
and time-of-day clock)
timing facility damage (machine-check interruption
condition) 179,175
TLB (translation lookaside buffer) 64 TOD dock (see time-of-day clock) TOD dock key 247
transfer in channel (TIC) I/O command 221
TRANSLATE (TR) instruction 145
example 303 TRANSLATE AND TEST (TR T) instruction 145
example 304 translation 60 exception address in main storage 79
lookaside buffer (TLB) 64
mode bit in PSW 33
process 61
326 System/370 Principles of Operation
translation (continued)
specification exception 79
table entries, states of 65
table modification 66
tables 59
(see also dynamic address translation)
two's complement, use of in fixed-point operations 116, 289
type of termination (in limited channel logout) 241
types of channels 188
types of (storage) addresses 62
unit
check (I/O unit status condition) 232
deletion (machine-check handling) 172
exception (I/O unit status condition) 233
of information (the byte), basic 14
of operation 74
unit status, I/O conditions 229,237
validity flag 241
unnormalized floating-point operation 159 UNPACK (UNPK) instruction 146
example 305 update (type of storage operand reference) 25
use of translation lookaside buffer 65
valid CBC 172
validation
of keys in storage 173
of registers 173
of storage 173
validity bits (in machine-check interruption code) 180 variable field length of operands 14
virtual
address 57
storage 57
volatile main storage 14
wait indicator 248
wait/running CPU state 30 bit in PSW, BC mode 34
bit in PSW, EC mode 35
warning
machine-check interruption condition 179, 175
mask bit 182
word (definition) 14
word-concurrent fetch 27
working (state of I/O system) 192
working device, effect of reset on 195
wraparound of main storage addressing 14
wraparound of register addresses in LOAD MULTIPLE 132
write command, I/O 2i8
WRITE DIRECT (WRD) instruction 114
X field of an instruction 20 ZERO AND ADD (ZAP) instruction 155
example 309 zone and sign codes in decimal operands 147, 148