ref: 8c71f0f0d3789b796540fec33641125f187537dd
dir: /src/plan9_builtins.c/
int __builtin_ctz(unsigned int x) { unsigned int r; if(x == 0) return 32; for(r = 0; (x & 1) == 0; x >>= 1, r++); return r; } int __builtin_clz(unsigned int x) { unsigned int r; if(x == 0) return 32; for(r = 0; (x & (1UL<<31)) == 0; x <<= 1, r++); return r; } int __builtin_clzll(unsigned long long x) { unsigned long long r; if(x == 0) return 64; for(r = 0; (x & (1ULL<<63)) == 0; x <<= 1, r++); return r; }