360 Assembly/360 Instructions/ISK

ISK - Insert Storage Key - Opcode 09 - RR Instruction (360 Only) Privileged Instruction

Format edit

Opcode edit

RR Instruction (2 bytes)
Byte 1
bits (0-7)
Byte 2
target register
source register
(in hex) Opcode
(4 bits)
0..F / (dec 0..15)
(4 bits)
0..F / (dec 0..15)
  • The first argument is a target register which value is affected by the instruction.
  • The second argument is the source register.
  • The target register and source register values are 0 to 15.

Example usage edit


Availability edit

The ISK instruction is available only on 360 models. It is a privileged instruction.

Purpose of Instruction edit

This instruction is used to get the Storage Key for the address specified in the Second operand and store into the first operand's bottom byte(1byte). ISK instruction provides support to get the storage key in 2K units of Page. ISKE will get the storage key for the 4K units of page.

Typical Usage edit

Operation edit

This is a privileged instruction, and is only available on the 360 series. The ISKE instruction is available on later 370 and zSystem processors.

Condition Codes edit

Condition codes are not changed.

Exceptions and Faults edit

  • Privileged Operation
  • Invalid Opcode (370 and z/System)
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