On Mon, 6 Oct 2003 11:34:39 +0200, you wrote:

>jumanji wrote :
>
>> Actually I meant something like: "one 'set' bit that rotates over 2 =
bytes"
>
>OK. Doesn't change much. So you startup by putting
>15 zeros and 1 one in the two bytes in some initialization
>routine and then rotate all bits, right ?
>The rotate code below dosn't care what's in the bytes, of course,
>but rotating 16 zeros or 16 ones would be hard to debug :-)
>
>Jan-Erik.
>PS.
>It should aso be said that you use the 18-series,
>on the 16-series you should use RLF instead of RLCF...
>
>
>> To rotate *all* bits in two bytes left :
>> (bit 7 of byte 2 goes into bit 0 of byte 1 and
>> bit 7 of byte 1 goes int0 byte 0 of byte 2)
>>   bsf     status, c     ;Setup carry flag...
>>   btfss   byte2,7       ;...according to bit 7
>>   bcf     status, c     ;...of byte 2
>>   rlcf    byte1         ;rotate carry into byte 1
>>   rlcf    byte2         ;same for byte 2
>>
>> Jan-Erik.

It's even easier than that if you don;t need to preserve W :=20
(16Cxx code):=20
rlf byte2,w ; carry from bit 7
rlf byte1
rlf byte2

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