>     What I want to do exactly is to have to variables, one with the port I
>want to use (let4s call it "port") and another one with the bit I want to
>read (let4s call it "bit") then use the instruccion btfss.
>
>     Something like this:
>
>     porta --> port
>     3 -->    bit
>
>     btfss    port, bit
>
>     What should mean btfss porta, 3
>
>     Is it possible?

I don't believe you can use a file (e.g. "bit") as a variable in this
instance.  It would return the location of the register, not the contents.
You would have to set "bit EQU 0x03" to make it work in this case.  Even so,
you couldn't change it by incrementing the register.  You'd have to use "bit
+ 1" next time around and have already defined "bit + 1 EQU 0x04" or
whatever bit you want to test.

You'd be better off just saving the contents of the port to a temporary
register and checking the bits by shifting them into carry:

  movf  PORTB, 0
  movwf  port_contents
  movf  bit_to_test, 0  ; check whatever bit # you want
  movwf  count
  sublw  0x07      ; must be <= 7
  btfss  STATUS, C
  goto  skip_check
  incf  count      ; bit 0 needs one rrf
  clrc
Loop
  rrf  port_contents
  decfsz  count
  goto  Loop
  btfss  STATUS, C    ; check the desired bit
  goto  bit_was_clear
  goto  bit_was_set
skip_check
....


Hope this is what you need.

--Andrew
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