Z86E3016PSG Datasheet, PDF (276/348 Pages) Zilog, Inc. – Z86E3016PSG

Z8 Family of Microcontrollers
User Manual
258
Interrupt Return
IRET
Instruction Format
OPC
Cycles
16
OPC
(Hex)
8F
Operation
FLAGS ← @SP
SP ← SP + 1
PC ← @SP
SP ← SP + 2
IMR (7) ← 1
This instruction is issued at the end of an interrupt service routine. It
restores the Flag Register (Control Register FCh) and the PC. It also re-
enables any interrupts that are potentially enabled.
Flag
C
Z
S
V
D
H
Description
Restored to original setting before the interrupt occurred.
Restored to original setting before the interrupt occurred.
Restored to original setting before the interrupt occurred.
Restored to original setting before the interrupt occurred.
Restored to original setting before the interrupt occurred.
Restored to original setting before the interrupt occurred.
Example
If Stack Pointer Low Register FFh currently contains the value 45h, Reg-
ister 45h contains the value 00h, Register 46h contains 6Fh, and Register
47 contains E4h, the statement:
IRET
Op Code: BF
Instruction Description
UM001602-0904