《操作系统》的实验代码。
 
 
 
 
 

26 lines
538 B

#include <x86.h>
#include <stdlib.h>
static unsigned long long next = 1;
/* *
* rand - returns a pseudo-random integer
*
* The rand() function return a value in the range [0, RAND_MAX].
* */
int
rand(void) {
next = (next * 0x5DEECE66DLL + 0xBLL) & ((1LL << 48) - 1);
unsigned long long result = (next >> 12);
return (int)do_div(result, RAND_MAX + 1);
}
/* *
* srand - seed the random number generator with the given number
* @seed: the required seed number
* */
void
srand(unsigned int seed) {
next = seed;
}