This would probably waste too much port space but you could reverse the 'w'
register in two instructions if you wired two ports together like this:
RA0->RB7
RA1->RB6
RA2->RB5
RA3->RB4
RA4->RB3
RA5->RB2
RA6->RB1
RA7->RB0
and executed the code sequence
mov  RA,W
mov  w,RB