I was too quick on the trigger... That last example should be;

Code:
    if((portb ^ 15) == 0)
      nop();
Code:
     if((portb ^ 15) == 0)
00E8  300F      MOVLW 0x0F
00E9  0606      XORWF gbl_portb, W
00EA  1D03      BTFSS STATUS,Z
00EB  28ED      GOTO    label13


       nop();
00EC  0000      NOP
00ED        label13