;by Dmitry Kiryashov
I still don't see solution shorter than 35 clocks. I've couple of them.
1)
movfw x ;35 words/clocks
clrf x
rrf y,F
;
skpnc ;this part is repeated 8 times
addwf x,F
rrf x,F
rrf y,F
;
2)
movfw x ;35 words/clocks
rrf y,F
skpc
subwf x,F
rrf x,F ;Cy=1 always before
rrf y,F
;
skpnc ;this part is repeated 7 times
addwf x,F
rrf x,F
rrf y,F
;
decf x,f ;substract first Cy=1