On 11/13/2013 11:04 PM, Paolo Bonzini wrote: > Il 13/11/2013 03:40, Alexey Kardashevskiy ha scritto: >> I looked further and did not find any use of ffs/clz so I wonder what did >> you mean about bitops.h and what did I miss? I am confused. > > It's host-utils.h actually. The reason for the wrappers is twofold: > > (1) provide 32/64-bit functions instead of int/long/longlong; > > (2) support GCC <3.4. > > The wrappers are not usable where you have constant expressions as in > your case. So your original patch is good IMO, except for the __ at the > beginning of __BITNR.
There are 2 macros, one (BITNR) uses the other (__BITNR). What would the good name be for BITNR then? > > Paolo > >> So I would suggest the following instead (if I really needed this BITNR but >> I really do not :) ) >> >> === >> bitops: add BITNR macro >> >> This adds a macro to calculate the highest single bit set. If more than >> one bit is set, returns -1. > -- Alexey
