Problem with interrupts on the PIC

[JimWright949]

There are two ways to handle this.

If you are writing code in C use the #pragma interrupt InterruptHandlerLow according top the Microchip C compiler ref' doc:
http://www.microchip.com/download/to...b18/51288b.pdf
the basic context should be saved for you.

In assembler the code to do this is:
MOVWF W_TEMP ; W_TEMP is in virtual bank
MOVFF STATUS, STATUS_TEMP ; STATUS_TEMP located anywhere
MOVFF BSR, BSR_TEMP ; BSR located anywhere
;
; USER ISR CODE
;
MOVFF BSR_TEMP, BSR ; Restore BSR
MOVF W_TEMP, W ; Restore WREG
MOVFF STATUS_TEMP,STATUS ; Restore STATUS

Which is found at the end of section 9 of the Pic18F8520 data sheet.

-Jim