Stack Operation Of Interrupt Processing - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 3 INTERRUPT
3.9

Stack Operation of Interrupt Processing

If an interrupt is accepted, contents of the dedicated registers are automatically stored
in the system stack before branching to interrupt processing. Return from the stack is
also automatically performed when interrupt processing is completed.
I Stack operation when interrupt processing starts
With an accepted interrupt, CPU automatically stores the contents of the current dedicated
registers in the system stack in the following sequence:
1. Accumulator (A)
2. Direct page register (DPR)
3. Additional data bank register (ADB)
4. Data bank register (DTB)
5. Program bank register (PCB)
6. Program counter (PC)
7. Processor status (PS)
Figure 3.9-1 "Stack operation at start of interrupt processing" shows the stack operation when
interrupt processing starts.
Figure 3.9-1 Stack operation at start of interrupt processing
Immediately
before interrupt
00
SSB
H
SSP 08FE
H
0000 08FE
A
H
AH AL
ADB 00
01
DPR
H
PCB FF
00
DTB
H
803F
PC
H
20E0
PS
H
94
Memory
Address
08FF
H
08FE
SP
H
H
XX
H
XX
H
XX
H
H
XX
H
XX
H
H
XX
H
XX
H
H
XX
H
XX
H
XX
H
XX
L
H
XX
08F2
H H
Byte
Immediately
after interrupt
Address
08FF
SSB
00
H
08FE
SSP 08F2
H
A 0000 08FE
H H
AH AL
ADB
01 00
DPR
H
FF
DTB 00 PCB
H
PC 803F
H
20E0
PS
H
08F2
Memory
H
SP
H
00
H
AH
00
H
08
H
AL
FE
H
01
DPR
H
H
00
ADP
H
00 DTB
H
H
FF PCB
H
80
H
PC
3F
H
20
H
PS
E0
H H
SP after
updating
Byte