>     xorlw  (0x05 ^ 0x20)    ; CV545

Harry, as Maarten said, the 5 restores W, and 20 is the next test. Here's
one I use for checking a character in a serial string. The commented
XORLW values are what are executed (ie what's in Program Memory).

         movfw   indf0
chk_n    xorlw   "N"  ;XORLW 0x4e
         bnz     chk_f        ;if not "N"
         bsf     off_on       ;else set to "device on"
         bra     ss

chk_f    xorlw   "N"^"F"  ;XORLW 0x08
         bnz     chk_st       ;if not "F"
         bra     ss           ;else leave as "device off"

chk_st   xorlw   "F"^"S"      ;XORLW 0x15
         bz      st_req       ;status request
         bra     ss

If you follow the bit patterns in binary you'll see how it works, for example

W ^ 0x4e
W ^ 0x4e then W ^ 0x46

  4e 01001110
^ 46 01000110
  --------------
  08 00001000

Here's another one

goes_hi  movfw   dev_no      ;set test bit, goes high
         xorlw   .1
         bnz     h2
         movlw   .1
         iorwf   instath
         bra     in_rdy
h2       xorlw   .1^.2       ;restore, test new value
         bnz     h3
         movlw   .2
         iorwf   instath
         bra     in_rdy
h3       xorlw   .2^.3
         bnz     h4



-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist