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Main task
Interrupt
service task
Interrupt acceptance
Interrupt return
Switching occurs to
the register bank BANK1.
A return is made automatically to
the register bank BANK0.
LD (RBS),1
The register bank
BANK0 is in use.
Figure 3-5 Saving/Restoring General-purpose Registers under Interrupt Processing
3.5.4
Interrupt return
Interrupt return instructions [RETI]/[RETN] perform as follows.
[RETI]/[RETN] Interrupt Return
1. Program counter (PC) and program status word (register bank) are re-
stored from tha stack.
2. Stack pointer (SP) is incremented by 3.
TMP89FH42
3. Interrupt Control Circuit
3.5 Interrupt Sequence
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RA003