Flag Manipulation and a Processor Control Instructions
These instructions control the functioning of the available hardware inside the processor chip. These instructions are categorized into two types:

  1. Flag Manipulation instructions.
  2. Machine Control instructions.

1. Flag Manipulation instructions
The Flag manipulation instructions directly modify some of the Flags of 8086.

  1. CLC – Clear Carry Flag.
  2. CMC – Complement Carry Flag.
  3. STC – Set Carry Flag.
  4. CLD – Clear Direction Flag.
  5. STD – Set Direction Flag.
  6. CLI – Clear Interrupt Flag.
  7. STI – Set Interrupt Flag.

2. Machine Control instructions

The Machine control instructions control the bus usage and execution

  • WAIT – Wait for Test input pin to go low.
  • HLT – Halt the process.
  • NOP – No operation.
  • ESC – Escape to external device like NDP
  • LOCK – Bus lock instruction prefix.



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