[操作系统实验lab2]实验报告

static void * alloc(u_int n, u_int align, int clear)
{
    extern char end[];  
    int i;
    u_long alloced_mem;
    if(freemem==0)
        freemem=(u_long)end;
    freemem = (((u_long)(freemem))+(align)-1)&~((align)-1);
    //Step 1 finished.
    alloced_mem = freemem;
    //Step 2 finished.
    freemem +=(((u_long)(n))+(align)-1)&~((align)-1);
    //Step 3 finished.
    if(clear == 1){
        for(i=alloced_mem;i<alloced_mem+n;i++)
             *i = 0;
    }
    //Step 4 finished.
    return (void *)alloced_mem;
    //Step 5 finished.
}