I am looking for a code fragment which calcuates the two's complemnt of a 32
bit word (4 bytes)

I'd prefer a specific code fragment.

The fragment below is close, but it doesn't work

;This changes BARG into -BARG in two's complement form
; BARGB3 is the low byte,.... BARGB0 is the high byte

neg_BARG        comf    BARGB3
                incf    BARGB3
                btfsc   STATUS,Z
                decf    BARGB2
                comf    BARGB2
;
                incf    BARGB2
                btfsc   STATUS,Z
                decf    BARGB1
                comf    BARGB1
;
                incf    BARGB1
                btfsc   STATUS,Z
                decf    BARGB0
                comf    BARGB0
                retlw   0


Thank you