NEC PD754144 - Manual (Page 289)

CHAPTER 11 INSTRUCTION SET
289 User’s Manual U10676EJ3V0UM
11.4.14 CPU control instruction
HALT
Function: PCC.2 ← 1
Sets the HALT mode (this instruction sets the bit 2 of the processor clock control register).
Caution
Make sure that a NOP instruction follows the HALT instruction.
STOP
Function: PCC.3 ← 1
Sets the STOP mode (this instruction sets the bit 3 of the processor clock control register).
Caution
Make sure that a NOP instruction follows the STOP instruction.
NOP
Function: Executes nothing but consumes 1 machine cycle.