Samsung S3F80JB manual Exit Exit, Operation IP, @Sp, Format Bytes

INSTRUCTION SETS3F80JB

EXIT — Exit

EXIT
Operation: IP	←	@SP
SP	←	SP + 2
PC	←	@IP
IP	←	IP + 2

This instruction is useful when implementing threaded-code languages. The stack value is popped and loaded into the instruction pointer. The program memory word that is pointed to by the instruction pointer is then loaded into the program counter, and the instruction pointer is incremented by two.

Flags:	No flags are affected.
Format:
			Bytes	Cycles	Opcode (Hex)
		opc	1	14 (internal stack)	2F
				16 (internal stack)

Example: The diagram below shows one example of how to use an EXIT statement.

Address
	IP	0050
	PC	0040
	SP	0022
	20
		IPH
21		IPL
22		Data

Stack

Before

Data

Address

50 PCL old

51 PCH

140 Exit

00

50

Memory

Data

60

00

2F

Address

IP 0052

PC 0060

SP 0022

22Data Stack

After

Data

Address

60

Data

Main

Memory

6-42