1. Introduction to Computing Systems (1st Exam)

2. 1. [10] What is the range of decimal integers that can be represented by the following given numbers of bits? (a) 1 (b) 2 (c) 4 (d) 8 (e) 12 (a) [-1,0] (b) [-2,-1,0,1] (c) [-8,-7,…,6,7] (d) [-128~+127] (e) [-2048~+2047]

3. 2. [15] Convert the following decimal numbers to 8-bit 2’s complement binary numbers. (a) 0 (b) 65 (c) 127 (d) -64 (e) -128 (a) 00000000 (b) 01000001 (c) 01111111 (d) 11000000 (e) 10000000

4. 3. [15] Convert the following 2’s complement binary numbers to decimal numbers. (a) 11111010 (b) 01011000 (c) xFE (d) x81 (e) x6F (a) -6 (b) 88 (c) -2 (d) -127 (e) 111

5. 4. [20] Compute the following operations on decimal numbers by the addition of 2’s complement numbers. Assume that 8 bits are used for a 2’s complement binary number. Express the results in 2’s complement notation. (a) 32+56 (b) 32-56 (c) -32+56 (d) -32-56 (e) -(32+56)

8. 7. [15] Assume that each character is represented by a parity- check bit followed by its corresponding ASCII code, and that even parity policy is adopted. (a) [10] Convert the character string “How are you?” to a binary string of ASCII codes. Express the result is hexadecimal notation. (b) [5] Suppose your e-mail system receives the following binary string x4869ACA0B721. What is the character string to appear on your screen? (a) x486F77A0E17265A0F96FF53F H:48 o:6F w:77 sp:A0 a:E1 r:72 e:65 sp:A0 y:F9 o:6F u:F5 ?:3F (b) “Hi, 7!”