Re: [問題] 關於中興95年計概轉學考考題

[future1234 (Creep)]

※ 引述《hothero (hothero)》之銘言：
: (a)A single board computer has four data register (R0 to R3),1024 words
: in memory,and 16 different instructions (Add,Subtract,Load,etc.),and the
: length of a program is limited within 512 lines.What is the minimum size of
: an instruction in bits if a typical instruction uses the format:Load [123] R1,
: which means to load the data at the address 123 to register R1.

Instruction Format:

   op    rd    address

  0000   00   00.....00


op:opcode , 可以做16個運算 , 4個bit去表示

rd:register destination operand, 在這R0 to R3 ,2個bit

address:假設1個 word= 8 bytes=64 bits , 1024 words就總共2^16 , 16個bit


所以指令長度是 4+2+16= 22 bits


: (b)If the computer uses the same size of word for data and instructions,
: what is the size of each data register?

Pentium架構的cpu:

    一個word=64 bits

: (c)What is the size of the program counter in bits?

         64 bits

: (d)What is the size of the address bus?

         36 bits  (Addressable 64G)


  (e)What is the size of the control bus?

         I don't know.

--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 203.67.210.63
推 hothero:我有問題，(a)為什麼假設1word=8bytes不是1byte阿??
→ hothero:(b)是怎麼知道他是pentium的cpu阿??
→ hothero:(c)program counter的大小是參考位址線還是資料線呢??
→ hothero:(D)為什麼(A)的address是16bits，這變成36bits了??
→ hothero:sorry，問題有點多>"<~謝謝
→ future1234:你怎現在才問= =
推 hothero:呵呵，因為問很久了...剛剛才發現>"<