Button interrupt MPASM code

   processor 12F629

    cblock 0x20
        d1
        d2
        button
        INT_CONTEXT_W
        INT_CONTEXT_STATUS
    endc

    #include 
    __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON & _MCLRE_OFF

    errorlevel -302

    org 0
    goto main

           
; --------------Interrupt start -----------------------------------
    org 0x4
; On an interrupt, the PIC only pushes the PC on the stack. 
; Program has to save the context !
    movwf INT_CONTEXT_W  ;save w in INT_CONTEXT_W
    movf STATUS, W 
    movwf INT_CONTEXT_STATUS    ;save STATUS in INT_CONTEXT_STATUS

; Light up the red LED if the button is pressed and not otherwise.
    bcf STATUS, RP0  ; select bank 0 
    btfss button,0 ; if set, skip line
    goto $+4
    bcf button,0    ; clear button
    clrf GPIO        
    goto $+4        ; skip next 3 lines
    bsf button,0    ; set means toggle
    bsf GPIO,0      ; turn GP0 on 
    bcf GPIO,1        
; Manually clear the interrupt flag.
    bcf INTCON, INTF   ; clear GPIF, Port Change Interrupt Flag bit

; Restore STATUS and W
    movf INT_CONTEXT_STATUS, W
    movwf STATUS
    movf INT_CONTEXT_W, W

    retfie  ;Return from interrupt
;-----------------interrupt end-------------------------------------
main

    bcf STATUS, RP0  ; select bank 0
    bcf button, 0 ; set button to 0
    movlw 0x00
    movwf GPIO    ; GPIO = 0000 0000

; Disable the comparator, this lets pins GP{0,1,2} act as digital I/O pins.
    movlw b'111'  ; 0x03
    movwf CMCON
    bsf STATUS, RP0    ; select bank 1
    movlw b'00000100'  ;  GP2 is input
    movwf TRISIO
; Enable external interrupt on GP2 .
    ;bsf IOC, IOC2     ; INTERRUPT-ON-CHANGE GPIO REGISTER, set GP2 
    bsf INTCON, PEIE  ;  set bit 6
    bsf INTCON, GIE   ;   set bit 7
    bsf INTCON, INTE  ; external interrupt GP2
    bsf OPTION_REG, INTEDG ; rising edge        
    bcf STATUS, RP0 ; select bank 0

loop:

		;99998 cycles
	movlw	0x1F
	movwf	d1
	movlw	0x4F
	movwf	d2
Delay_0
	decfsz	d1, f
	goto	$+2
	decfsz	d2, f
	goto	Delay_0

    btfss button,0  ; if bit 0 == 1, skip next line
    goto $+3        
    movlw b'00000011' ; Toggle LEDs
    xorwf GPIO, F     ; xor GPIO with 0000 0010 ^ 0000 0011
    goto loop

    end