IBM System/370 145 Reference Summary page 28

EXPANDED LOCAL STORAGE
I-CYCLE STATUS REGISTER
Definition of Exp LS 56
ICS Byte 2
0
2
3
BR Read Latch
Op Load Latch
Op L2
Op Ll
4 Prefetch Required
5
Prefetch Inhibit
6
FLP Long
7
Op Br to DF
3
4
5
6
IMM Byte Modifier Parity Check
X=O
B=O
Set Control Address
7 Low Bit
EXP LS 56 (ICS) is intended for use only as
r
manual display and can't be accessed via
microcode.
When in I-cycles (DF Module) the line generate
address is functionally overridden during
~ddresses
DFOO and DF10.
If both index and base indicators are off, double
indexing will take place.
I-CYCLES
Rtn Lnk
GICM B40C
Handle Interrupt
Then Issue Rtn Lnk
Uses LS30 for Rtn
Data
in
Buffers
Not Good
OFOC
ROW, Y ADJ,
V+4
Fetch Required
RDW,Y
ADJ, V
Further Fetch
DF10
y ""y,SO
Time Delay
GAA1 C564
Spec1f1cat1on
Check
Turn on Op
Load Latch
Branch On
Op Code
Format
I-CYCLES
GAAR
CQOO.CJFX
DFA4
DFSO
DF84
DFOC
GARX
C480- C4CO
GAAR
C140 C1FO
GARA
C28X · C2FX
GARR
C38X- C3FX
GASS
CCOO- CFFO
Instruction Without Prefetch With Prefetch
RR (Not FP Long)
DF20
DF34
DF30
AR (FP Long) DF24 - DF28 DF3C
DF2C
DF28
RX (Double Index) DF4C DF40 DF58 DF40
RS,Sl,RX (Not Double Index) DF48 DF58
SS OF6C
DFGO OF7C- DF70
PSW LOCATIONS
3145 Models
System Mask Key OWMP
Interrupt Code
0 7 8 11 12 15 16 31
I
External 10 EXP LS 50 1 EXP LS 53
ILC
cc
32 33 34
EXP LS 53
I
ByteO t ByteO
Bit 0, 1 I Bit 2, 3
'
Byte o :svte 1
I
Program Mask
35
36
37
38
EXP LS 53
ByteO
B1ts4-7
2.3
Instruction Address
39
40 63
EXP LS 50
Bytes 1, 2, 3
II