Control Word Formats
Base andilndex Registers
*
B.ase Addressor Index 7 8 31 0-7 Ignored
8-31 Base address or indexProgram Status Word I System Mask Key I AMWP I Interruption Code
o 78 1112 1516 31Instruction Address
32 3334 35 36 39 40 63 0-7 System mask 13 Machine check mask 0 Multiplexor channel (M)
mask 14 Wait state (W)
1Selector channel 1 15 Problem state (P) mask 16-31 Interruption code
2 Selector channel 2 32-33 Instruction length
mask code (ILC)
3Selector channel 3 34-35 Condition code (CC)
mask 36-39 Program mask
4Selector channel 4 36 Fixed-point overflow
mask mask
5Selector channel 5 37 Decimal overflow
mask mask
6 Selector channel 6 38 Exponent underflow
mask mask
7 External mask 39 Significance mask
8-11 Protection key40-63 Instruction address
12 ASCII mode (A)Channel Command Word
Command
Data Address
J
Code
7 8 31C Flags IOOO[ *
Count
363:r 3940 4748 630-7 Command code 35 Skip flag
8-31 Data address 36 Program-controlled
32-36 Command flags interruption flag
32 Chain data flag 37-39 Zero
33 Chain command flag40-47 Ignored
34 Suppress length 48-63 Count
indication flag
144Command Code Assignment FLAGS NAMES Write
Read
Read Backward
Control
Sense
CD CCSLI PCI CD CC SLI SKIP PCI CD CC SLI SKIP PCI CD CC SLI PCI CD CC SLI SKIP PCI CODE MMMMMMOI MMMMMM10
MMMM1100 MMMMMMll
MMMM0100 x x x x 1000 Transfer in Channel
CD
CCSLI Chain data
Chain command
Suppress length
indicationChannel Address Word SKIP PCI Skip
Program
controlled
interruptionIr- ____ -, ____________ .- ____________________________________________________________ I Key [ 000 0 1 Command Address 34 7 8 31 0-3 Protection key
4-7 Zero
8-31 Command addressChannel Status Word
Command Address34 7 8 31 Status Count
32
47 48 630-3 Protection key 40 Program-controlled
4-7 Zero interruption
8-31 Command address 41 Incorrect length
32-47 Status 42 Program check
32 Attention 43 Protection check
33 Status modifier 44 Channel data check
34 Control unit end 45 Channel control check
35 Busy 46 Interface· control
36 Channel end check
37 Device end 47 Chaining check
38Unit check 48-63 Count
39U nit exception
Base and
*
B.ase Address
8-31 Base address or index
o 78 1112 1516 31
32 33
mask 14 Wait state (W)
1
2 Selector channel 2 32-33 Instruction length
mask code (ILC)
3
mask 36-39 Program mask
4
mask mask
5
mask mask
6 Selector channel 6 38 Exponent underflow
mask mask
7 External mask 39 Significance mask
8-11 Protection key
12 ASCII mode (A)
Command
Data Address
J
Code
7 8 31
Count
363:r 3940 4748 63
8-31 Data address 36 Program-controlled
32-36 Command flags interruption flag
32 Chain data flag 37-39 Zero
33 Chain command flag
34 Suppress length 48-63 Count
indication flag
144
Read
Read Backward
Control
Sense
CD CC
MMMM
MMMM
CD
CC
Chain command
Suppress length
indication
Program
controlled
interruption
4-7 Zero
8-31 Command address
Command Address
32
47 48 63
4-7 Zero interruption
8-31 Command address 41 Incorrect length
32-47 Status 42 Program check
32 Attention 43 Protection check
33 Status modifier 44 Channel data check
34 Control unit end 45 Channel control check
35 Busy 46 Interface· control
36 Channel end check
37 Device end 47 Chaining check
38
39