[理工] [計組]98交大第4題

看板Grad-ProbAsk作者 (Den)時間13年前 (2013/01/21 22:41), 編輯推噓0(007)
留言7則, 2人參與, 最新討論串1/1
Consider a virtual memory system with the following properties: 12-bit virtual byte address 256-byte pages 65536 bytes of physical memory The system uses a single level page table. The contents of the page table are partially shown below (where VPN: Virtual page number and PPN: Physical page number). (i)(3%) What is the total size of the page table for each process on this machine,assuming that the valid, protection, dirty, and use bits take a total of 4 bits and that all the virtual pages are in use? 解答是 2^4 * (8+4)/32 * 4 請想問(8+4)/32 * 4 這個數字是怎麼來的 爬文以後的解釋看不懂。麻煩板上的高手了 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 36.224.32.56

01/21 22:52, , 1F
2^4<--pagetable的entry數,4(statusbit)+(16-8)(PPN)
01/21 22:52, 1F

01/21 22:53, , 2F
兩個相乘就是答案咧,他應該是把大小從bit轉成byte
01/21 22:53, 2F

01/21 22:55, , 3F
因為另一篇的是寫round up to word看不太懂意思@@
01/21 22:55, 3F

01/21 22:58, , 4F
我猜的喔...我不准正我答案正確xd
01/21 22:58, 4F

01/21 23:00, , 5F
如果是roundtoword應該是存在memory要對齊吧
01/21 23:00, 5F

01/21 23:01, , 6F
所以2^4*[8+4/32]*4 byte這樣才對!
01/21 23:01, 6F

01/21 23:03, , 7F
哦哦哦 大概懂意思了 謝謝B大的解答
01/21 23:03, 7F
文章代碼(AID): #1G_LEnIa (Grad-ProbAsk)