ref: af68820de45fb5675495e70c38d2688138701936 dir: /plan9_builtins.c/
#include "platform.h" 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; }