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HARDWARE
38K2 Group
FUNCTIONAL DESCRIPTION
On-going Routine
Interrupt request
(Note)
M (S)
Execute JSR
Push return address
on stack
M (S)
(PCH)
(S)
(S) – 1
M (S)
(PCL)
(S)
(S)– 1
(S)
M (S)
(S)
M (S)
(S)
Subroutine
POP return
address from stack
(S) + 1
(PCL)
M (S)
(S)
(S) + 1
(PCH)
M (S)
(S) – 1
(PCL)
Push return address
on stack
(S) – 1
(PS)
Push contents of processor
status register on stack
(S) – 1
Interrupt
Service Routine
Execute RTS
(S)
(PCH)
I Flag is set from “0” to “1”
Fetch the jump vector
Execute RTI
Note: Condition for acceptance of an interrupt
(S)
(S) + 1
(PS)
M (S)
(S)
(S) + 1
(PCL)
M (S)
(S)
(S) + 1
(PCH)
M (S)
POP contents of
processor status
register from stack
POP return
address
from stack
Interrupt enable flag is “1”
Interrupt disable flag is “0”
Fig. 6 Register push and pop at interrupt generation and subroutine call
Table 3 Push and pop instructions of accumulator or processor status register
Push instruction to stack
Pop instruction from stack
Accumulator
PHA
PLA
Processor status register
PHP
PLP
Rev.2.00 Oct 15, 2006
REJ09B0338-0200
page 8 of 130