Introduction to Computer Systems

Introduction to Computer Systems

Part I – Short Answer Questions (Provide brief answers to the following questions)

1) If there are 50 students in our class and every student is assigned a unique bit pattern, what is the minimum number of bits required to do this?

2) What is the greatest magnitude negative number one can represent in a 5-bit 2’s complement code? Write your result in binary and decimal. (Magnitude: -3 has a greater magnitude than -2)

3) Convert (a) and (b) to 8-bit 2’s complement binary numbers. Consider (b) as a 2C value. Consider (c) and (d) as 8-bit 2’s complement binary numbers and convert them to decimal.

4) The following are 2’s complement binary numbers. Perform the following operations & indicate if any of the operations generate overflow.

5) If a CMOS circuits outputs a 1, what must be true (select all that apply by underlining them):

a. A pathway exists in the circuit between the output and power source

b. All NMOS transistors must be off

c. All PMOS transistors must be on

d. The PDN must be on

e. All of the above

f. None of the above

6) What is the purpose of an ISA?

7) What is the address space, addressability, and total capacity of the LC4s memory?

8) In the LC4’s ISA, why don’t the “compare” instructions set regFile.WE=1 ?

9) What is the difference between an “immediate” instruction and non-immediate instruction? In each case, where is the data coming from?

10) Why is the OPCODE for the MOD instruction different from the rest of the arithmetic instructions?