TMP86FS49AFG Toshiba Semiconductor, TMP86FS49AFG Datasheet - Page 57

• Manufacturer Part Number: TMP86FS49AFG
• Description: 8-Bit Microcontroller
• Manufacturer: Toshiba Semiconductor

Example :Save/store register using data transfer instructions
Example 1 :Returning from address trap interrupt (INTATRAP) service program
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3.3.3 Interrupt return
Figure 3-4 Saving/Restoring General-purpose Registers under Interrupt Processing
restarting address, during interrupt service program.
Interrupt return instructions [RETI]/[RETN] perform as follows.
As for address trap interrupt (INTATRAP), it is required to alter stacked data for program counter (PC) to
Note:If [RETN] is executed with the above data unaltered, the program returns to the address trap area and
PINTxx:
PINTxx:
INTATRAP occurs again.When interrupt acceptance processing has completed, stacked data for PCL and
PCH are located on address (SP + 1) and (SP + 2) respectively.
Saving/Restoring general-purpose registers using PUSH/POP data transfer instruction
LD
(interrupt processing)
LD
RETI
POP
LD
PUSH
(interrupt processing)
RETN
Main task
1. Program counter (PC) and program status word
2. Stack pointer (SP) is incremented by 3.
(PSW, includes IMF) are restored from the stack.
(GSAVA), A
A, (GSAVA)
WA
WA, Return Address
WA
Interrupt
acceptance
[RETI]/[RETN] Interrupt Return
Interrupt return
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Interrupt
service task
; Restore A register
; Alter stacked data
; Save A register
; RETURN
; Recover SP by 2
;
; RETURN
Saving
registers
Restoring
registers
TMP86FS49AFG