rand.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */
#include <precomp.h>

#include <internal/tls.h>

/*
 * @implemented
 */
int
rand(void)
{
  PTHREADDATA ThreadData = GetThreadData();

  ThreadData->tnext = ThreadData->tnext * 0x5deece66dLL + 2531011;
  return (int)((ThreadData->tnext >> 16) & RAND_MAX);
}

/*
 * @implemented
 */
void
srand(unsigned int seed)
{
  PTHREADDATA ThreadData = GetThreadData();

  ThreadData->tnext = (ULONGLONG)seed;
}