4
4-9
EIT
32180 Group User’s Manual (Rev.1.0)
4.6 Saving and Restoring the PC and PSW
PSW BPC PC
When EIT is accepted
When RTE instruction
is executed
[1] Saving the SM, IE and C bits
BSM
BIE
BC
SM
IE
C
←
←
←
[2] Updating the SM, IE and C bits
SM
IE
C
Unchanged or 0
0
0
←
←
←
[3] Saving the PC
BPC
PC←
[4] Setting the vector address in the PC
PC
Vector address←
[B] Restoring the PC from the BPC register
The value stored in the BPC register
after executing the RTE instruction is
undefined.
[A] Restoring the SM, IE and C bits from the
backup field
SM
IE
C
The values stored in the BSM, BIE
and BC bits after executing the RTE
instruction are undefined.
BSM
BIE
BC
←
←
←
[1]
[A] [B]
[2]
[3]
[4]
Figure 4.6.1 Saving and Restoring the PC and PSW
16 17 23 24 25 31(LSB)15870(MSB)
SM IE CBCBSM BIE
00000000000000000000000000
PSW
BPSW field PSW field
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