UPD784938 Datasheet, PDF (553/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 23 INTERRUPT FUNCTIONS
The RETCS instruction is used to return from an interrupt that uses the context switching function. The RETCS instruction
must specify the start address of the interrupt service program to be executed when that interrupt is acknowledged next.
This interrupt service program start address must be in the base area.
Caution The RETCS instruction must be used to return from an interrupt serviced by context switching.
Subsequent interrupt acknowledgment will not be performed normally if a different instruction is used.
Figure 23-12. Return from Interrupt that Uses Context Switching by Means of RETCS Instruction
PC19 to 16
PC15 to 0
1 Restoration
2 Restoration
4 Restoration
(to original
register bank)
PSW
Register bank n (n = 0 to 7)
A
X
B
C
R5
R4
RETCS instruction operand
3 Transfer
R7
R6
V
VP
U
UP
T
D
E
W
H
L
Preliminary User’s Manual U13987EJ1V0UM00
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