Arizona Picdem 17 - Manual (Page 36)

PICDEM™ 17 Demonstration Board User’s Guide
DS39024B-page 30  2001 Microchip Technology Inc.
; Branch to prolog
movlw HIGH _T0CKI_prolog
movwf PCLATH
movlw LOW _T0CKI_prolog
movwf PCL
;-----------------------------------------------------------;
;***********************************************************;
_PIV_sec CODE H’4020’
;-----------------------------------------------------------;
; Save ALUSTA
movpf ALUSTA, save_ALUSTA ; must save ALUSTA before others
movpf WREG, save_WREG ; temporarily save off WREG
; Branch to prolog
movlw HIGH _PIV_prolog
movwf PCLATH
movlw LOW _PIV_prolog
movwf PCL
;-----------------------------------------------------------;
;***********************************************************;
InterruptCode CODE
;-----------------------------------------------------------;
_INT_prolog
;Save BSR and WREG
movfp BSR, PCLATH
clrf BSR, 1
movpf PCLATH, save_BSR
;Service the interrupt by calling the interrupt
;handling function
goto _INT_2
_INT_1
BANKSEL fpINT
movfp fpINT+1, PCLATH
movfp fpINT, PCL
_INT_2
call _INT_1 ; push address of next instruction on stack
;Restore WREG and BSR
clrf BSR, 1 ;BSR was saved in bank 0
movfp save_BSR, BSR ;Now restore it
movfp save_WREG, WREG ;and WREG as well.
;Restore PCLATH and ALUSTA
movfp save_PCLATH, PCLATH
movfp save_ALUSTA, ALUSTA
;Return from interrupt
RETFIE
;-----------------------------------------------------------;
;-----------------------------------------------------------;
_TMR0_prolog