Quickest way to get highest set bit on port in to a variable?

[Art]

Ok,
In the listing he’s rotating left. I would think that would result in quicker times for the lower values.
I’m pretty sure there’s an error in my asm, as the example uses a different instruction to rotate with carry.
This is the same thing in BASIC but rotating right so the higher values should be found faster.
I’d be interested to enter a race with it.. just not sure some lines are converted the way I’d want them to.

workword var word
workbyte var workword.byte0 ‘ 1st byte
bitcarry var workword.8 ‘ 9th bit
bitcount var byte


NCD8:
bitcount = 8 ‘ mov l to w & w to f
workbyte = portX ‘ mov l to w & w to f

if workbyte = 0 then ‘ portX was zero
goto whatawaste
endif

inloop:
bitcount = bitcount - 1 ‘ decf
workword = workword << 1 ‘ 2 x rrf with carry

if bitcarry = 0 then ‘ btfss
goto inloop ‘ goto
endif
return

whatawaste:
bitcount = 0 ‘ bsf
return