myke predko <PICLIST@MITVMA.MIT.EDU> wrote:

> Does this mean that decfsz won't work on the [16C5x FSR registers]
> (because they can never be equal to zero)?

    Yes.

> And, when using the incfsz instruction on these registers, where do
> you put the result?  If the bits are always set to "1" and you
> specify putting the result back there, what happens?

    The "normal" use for the INCFSZ instruction (incrementing a loop
    counter -- or more typically, the low byte of a multi-byte loop
    counter -- until it overflows) requires that you put the result
    back into the register.  When you do an INCFSZ on the 16C5x FSR
    register, the PIC grabs the contents of the register (including
    the upper "1" bits), increments that number and decides whether
    to skip, then (essentially) ORs the result with "11100000" (for
    the 16C54/55/56) or with "10000000" (for the 16C57) and stores
    the result back into the FSR.

> Don't you hate it when you answer a question and more questions
> pop up?

    Nah... I live for that.

    -Andy

Andrew Warren - fastfwd@ix.netcom.com
Fast Forward Engineering, Vista, California
http://www.geocities.com/SiliconValley/2499