diff options
Diffstat (limited to 'util.c')
| -rw-r--r-- | util.c | 20 |
1 files changed, 14 insertions, 6 deletions
@@ -20,16 +20,24 @@ static u8 util_popcount(u64 x) { #endif } -static u8 util_count_leading_zeroes(u64 x) { +static u8 util_count_leading_zeroes32(u32 x) { + if (x == 0) return 32; // GCC's __builtin_clz is undefined for x = 0 #if __GNUC__ - return (u8)__builtin_clzll(x); +#if UINT_MAX == 4294967295 + return (u8)__builtin_clz(x); +#else + #error "unsigned int isn't 32 bits. this function needs fixing to work on sytems like yours." +#endif #elif _WIN32 - return (u8)__lzcnt64(x); + return (u8)__lzcnt(x); #else u8 count = 0; - for (int i = 63; i >= 0; --i) - if (x & ((u64)1<<i)) - ++count; + for (int i = 31; i >= 0; --i) { + if (x & ((u32)1<<i)) { + break; + } + ++count; + } return count; #endif } |