Comparison of instruction sets:
System/360, System/370, 370-XA
1. New instructions introduced in System/370, compared to System/360
Opcode Mnemonic Operation Ref in 370-XA Princs of Op
0D BASR Branch and save register 7-10
0E MVCL Move long 7-27
0F CLCL Compare logical long 7-17
4D BAS Branch and save 7-10
AC STNSM Store then AND system mask 10-44
AD STOSM Store then OR system mask 10-44
AE SIGP Signal processor 10-41
AF MC Monitor call 7-26
B1 LRA Load real address 10-18
B2xx Channel set, Clock, Timer
PURGE TLB, PREFIX, Ref bit,
PTE instructions, Cross-memory service
instructions
B6 STCTL Store control 10-42
B7 LCTL Load control 10-17
BA CS Compare and swap 7-14
BB CDS Compare double and swap 7-14
BD CLM Compare logical characters under mask 7-16
BE STCM Store characters under mask 7-38
BF ICM Insert characters under mask 7-23
D9 MVCK Move with key 10-20
DA MVCP Move to primary 10-19
DB MVCS Move to secondary 10-19
E500 LASP Load address space parameters 10-10
E501 TPROT Test protection 10-47
E8 + MVCI Move inverse
F0 SRP Shift and round decimal 8-10
The action of the following instruction is modified in System/370 depending on
the address mode bit in the PSW:
41 LA Load address. In 24-bit mode, the
top byte of the destination register
is set to zero. In 31-bit mode, the
destination register contains the
31-bit address.
Likewise the BAS and BASR instructions also depend on the current address mode.
In 24-bit mode they behave exactly as BAL, BALR respectively, but in 31-bit
mode the link register is set to contain the 31-bit address. The instruction
length code, condition code and program mask provided by BAL, BALR may be
obtained instead using the new instruction IPK Insert program mask.
THERE IS THEREFORE NO CASE for using BAL, BALR in the future, at least for
their branch function (they can still be used to get CC and PM into the top
byte of the operand-1 register) since BAS and BASR provide the necessary
forward and backward compatibility.
Most of the XA instructions are now implemented on the 370-XA simulator on
EMAS 2900, apart from those relating to key and PSW manipulation and dual
address space. The MVCI instruction marked + is not perpetuated in 370-XA.
2. New instructions for 370-XA
0B BSM Branch and set mode 7-11
0C BASSM Branch and save and set mode 7-11
99 TRACE Trace 10-48
B222 IPK Insert program key 7-23
B22D DXR Divide (extended) 9-8
And the following instructions
are withdrawn:
08 SSK Set storage key
09 ISK Insert storage key
84 Write direct
85 Read direct
B200-B201 Connect, disconnect channel set
B213 Reset reference bit (use extended form)
E8 MVCI Move inverse(!)
K Yarwood
10/1/84