Does anyone have a slick method for detecting rising or falling edges? I
keep ending up with a variation of these two methods, and both seem cheesy.
In this case I am trying to detect a falling edge on PORTA,4 and jump to
Index_now. I am using index_flag for storage.

First method, wastes the entire byte of index_flag:

                bcf     STATUS,C        ;clear carry flag
                btfsc   PORTA,4         ;test the port bit
                bsf     STATUS,C        ;set carry if pin was high
                rlf     index_flag,f    ;bit0=newpin bit1=oldpin
                movlw   b'00000011'     ;only care about bottom two bits
                andwf   index_flag,w    ;those bits are now in w
                xorlw   b'00000010'     ;compare with falling pattern 1 to 0
                btfsc   STATUS,Z        ;skip if the pattern doesn't match
                goto    Index_now       ;pattern matched, jump

OK, that was fun, but it was kind of wasteful. This next way only uses one
bit of the flag byte:

                btfss   PORTA,4         ;test the port pin
                goto    It_is_zero      ;jump if low
                bsf     index_flag,0    ;remember for next go 'round
                goto    Index_not       ;get out
It_is_zero      btfsc   index_flag,0    ;test if previously it was high
                goto    Index_now       ;we have a falling edge
Index_not                               ;default code here
Index_now       bcf     index_flag,0    ;remember for next time

This method is real typical of the stuff I've always done, but it still
seems a stupid way to do it.

Anybody got a quantum leap for me?

Thanks, Bob