ref: d376fac66cbd5efbe2f9f61a1e8b31af03a84a92
dir: /sys/src/libc/port/lnrand.c/
#include <u.h> #include <libc.h> #define MASK 0x7fffffffL long lnrand(long n) { long slop, v; if(n < 0) return n; slop = MASK % n; do v = lrand(); while(v <= slop); return v % n; }