GMS81508B HYNIX [Hynix Semiconductor], GMS81508B Datasheet - Page 63

• Manufacturer Part Number: GMS81508B
• Description: HYUNDAI MICRO ELECTRONICS 8-BIT SINGLE-CHIP MICROCONTROLLERS
• Manufacturer: HYNIX [Hynix Semiconductor]

GMS81508B/16B/24B
area for saving registers.
The following method is used to save/restore the general-
purpose registers.
Example: Register save using push and pop instructions
General-purpose register save/restore using push and pop
instructions;
60
INTxx:
main task
PUSH
PUSH
PUSH
interrupt processing
POP
POP
POP
RETI
interrupt return
acceptance of
interrupt
A
X
Y
Y
X
A
interrupt
service task
;SAVE ACC.
;SAVE X REG.
;SAVE Y REG.
;RESTORE Y REG.
;RESTORE X REG.
;RESTORE ACC.
;RETURN
saving
registers
restoring
registers
16.2 BRK Interrupt
Software interrupt can be invoked by BRK instruction,
which has the lowest priority order.
Interrupt vector address of BRK is shared with the vector
of TCALL 0 (Refer to Program Memory Section). When
BRK interrupt is generated, B-flag of PSW is set to distin-
guish BRK from TCALL 0.
Each processing step is determined by B-flag as shown in
Figure 16-5.
TCALL0
BRK or
Figure 16-5 Execution of BRK/TCALL0
HYUNDAI MicroElectronics
INTERRUPT
ROUTINE
B-FLAG
RETI
BRK
DEC. 1999 Ver 1.04
=1
=0
ROUTINE
TCALL0
RET