protected override MemBlock GetFirstMem(out int?dispage, int[] cmd = null, int current = -1)
{
MemBlock block = blocks.Max();
dispage = block.Page;
return(block);
}
protected override MemBlock GetFirstMem(out int?dispage, int[] cmds = null, int current = 0)
{
//FIFO状态下，新装入的内存永远在最后一位，最早装入的永远在最前位
MemBlock block = blocks[0];
dispage = block.Page;
blocks.RemoveAt(0);
blocks.Add(block);
return(block);
}
protected virtual MemBlock GetEmptyMem()
{
if (IsFull)
{
throw new Exception("Memory is full, no empty block");
}
var newBlock = new MemBlock();
blocks.Add(newBlock);
IsFull = blocks.Count >= count;
return(newBlock);
}
/// <summary>
/// 使用给定指令序列和内存块数进行制定模式的测试
/// </summary>
/// <param name="mc">内存块数</param>
/// <param name="cmd">指令序列</param>
/// <param name="mode">调度模式</param>
/// <returns>缺页率</returns>
public static double RunTest(int mc, int[] cmd, DispatchMode mode)
{
List <PageItem> table = new List <PageItem>(); //页表
MemoryList memory = MemoryListFactory.Create(mc, mode); //初始化内存和调度模式
for (int i = 0; i < cmd.Length / 10; i++)
{
table.Add(new PageItem()
{
Page = i
});
}
var accCount = 0; //命中次数
var failCount = 0; //缺页次数
for (int i = 0; i < cmd.Length; i++)
{
var next = table[cmd[i] / 10];
if (next.InMemory)
{ //指令在内存中，命中
accCount++;
if (mode == DispatchMode.LRU)
{ //若使用LRU调度模式，清空内存驻留时间
var mem = memory.GetMemByPage(next.Page);
mem.Time = 0;
}
}
else
{ //指令不在内存中，缺页中断，调页
failCount++;
MemBlock mem = null; //可用内存单元
int? dis = null; //移出页页号
mem = memory.GetMem(out dis, cmd, i);
next.InMemory = true;
mem.Page = next.Page; //目标页进入内存
mem.Time = 0; //清空内存驻留时间
if (dis != null)
{ //若有页被调出，将其在页表中的标志位设置false
table[(int)dis].InMemory = false;
}
}
memory.Refresh(); //刷新内存状态
#if DEBUG
Console.WriteLine("当前指令 -> {0}", cmd[i]);
memory.Show();
#endif
}
return(failCount * 100.0 / (failCount + accCount));
}