Table of Contents

Kernel Request (KER)/OP=90

Format

OP AF BF A Syllable

OP = 90

AF Length of the A Syllable data field. May be indirect. A value of 00 indicates that there are no units to be moved. A literal flag will cause an Invalid Instruction (IEX = 21) fault.
BF is an eight-bit kernel request code. May be specified as indirect.

The A Syllable is the address of the kernel data field. Address may be indexed, indirect or extended. The final address controller must be UN or cause an Invalid Instruction (IEX = 03) fault.

Function

The Kernel Request instruction is a programmatic method for requesting services from the kernel of the MCP.

This instruction may only be executed with Privileged Enable set or an Invalid Instruction (IEX = 02) fault is reported.

The following steps are performed to accomplish this operation:

  1. If the value of AF is greater than 40, cause an Invalid Instruction (IEX = 25) fault and terminate the instruction with no further action.
  2. Save the Kernel Request value within the processor for future update of the Instruction Interrupt Cause descriptor in the Kernel Data Area.
  3. Save the BF value within the processor for future update of the Instruction Interrupt Cause Extension descriptor in the Kernel Data Area.
  4. If AF is non-zero, save the A data field within the processor for future update of the MCP Kernel Request Data field in the Kernel Data Area.
  5. Perform an Interrupt Procedure that will report an Instruction Interrupt in the Interrupt descriptor field in the Kernel Data Area.

Comparison Flags

The Comparison Flags are not affected by this instruction.

Overlap

Field overlap is not applicable to this instruction.