计算机科学导论v10_练习1 2010.ppt

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 11. Using the machine language of Appendix C, write a program that places a 1 in the most significant bit of the memory cell whose address is A7 without modifying the remaining bits in the cell. 12A7 (A7)-R2 2380 80-R3 7023 R2 OR R3 -R0 30A7 (R0)-A7 C000 12. Using the machine language of Appendix C, write a program that copies the middle four bits from memory cell E0 into the least significant four bits of memory cell El, while placing 0s in the most significant four bits of the cell at location El . 15E0 (E0)-R5 A502 R5右移2bits 260F 0F-R6 8056 R5 AND R6 -R0 30E1 (R0)-E1 C000 QUESTIONS/EXERCISES(2.5) 1. Assume that the machine described in Appendix C uses memory mapped I/O and the address B5 is the location within the printer port to which data to be printed should be sent. a. If register 7 contains the ASCII code for the letter A, what machine language instruction should be used to cause that letter to be printed at the printer? b. If the machine executes a million instructions per second, how many times can this character be sent to the printer in one second? c. If the printer is capable of printing five traditional pages of text per minute, will it be able to keep up with the characters being sent to it in (b)? 37B5 a million 2. Suppose that the hard disk on your personal computer rotates at 3000 revolutions a minute and that each track contains 16 sectors, and each sector contains 1024 bytes. Approximately what communication rate is required between the disk drive and the disk controller if the controller is going to receive bits from the disk drive as they are read from the spinning disk? 3000 转/分钟=50转/sec 每秒 16 * 50 =800 sectors/sec 1024byte/sector 1024 * 800= 11200byte= 3. How long would it take to transfer a 300novel