Computer Architecture, Weeks 5-6

Front 1

What is a transistor?

Back 1

An electronic on-off switch.

Front 2

Combinational Logic Circuit vs Sequential Logic Circuit

Back 2

Combinational Logic Circuit: Current output is only dependent on current input.

Sequential Logic: Current output may depend on the past input also.

Front 3

Study these Boolean Identities.

Back 3

Front 4

What is the Sum of Product Form of a Boolean Function?

Back 4

Consider the truth table for the Majority Function shown in the picture.

Look at each row where the output is 1. Write each of the inputs as if they were 1.

For example, if A = 1, B = 0, and C = 1, write AB'C.

Front 5

What is the Product of Sum Form of a Boolean Function?

Back 5

Consider the truth table for the Majority Function shown in the picture.

Look for rows where the output is 0. Write each of the inputs as though they were all 0s.

For example, if A = 0, B = 1, and C = 0, then write (A + B' + C).

Front 6

The sum of product and product of sum forms of a Boolean function are called _________ ___________.

Back 6

Canonical representations

Front 7

What is a functionally complete set?

Back 7

A set of gates where if given enough supply of the gates, any Boolean function can be realized.

Front 8

List the functionally complete sets.

Back 8

AND-OR-NOT

AND-NOT

OR-NOT

NAND

NOR

Front 9

What is a Multiplexer?

Back 9

A circuit with 2^n data inputs, n control inputs, and one output.

The output matches one of the selected inputs.

(8x1 multiplexer shown in picture)

Front 10

What is a decoder?

Back 10

A circuit with n inputs and 2^n outputs.

Exactly one of the output lines is selected.

(three-to-eight decoder shown in picture)

Front 11

What is a Half Adder?

Back 11

Two input two output combinational logic circuit to perform addition of two bits.

Front 12

What is a full adder?

Back 12

Three input two output combinational logic circuit to perform addition of two bits, taking into account carry in.

Front 13

In an ideal situation, output appears as soon as the input is applied. In reality however, chips have a finite _____ ______.

Back 13

gate delay

Front 14

How do you read Verilog?

Back 14

The first variable of gates is the output, with the remaining variables as input to the gate.

Front 15

What is a clock?

Back 15

A circuit that emits a series of pulses with a precise pulse width and precise interval between consecutive pulses.

Front 16

Study the Clocked D Latch

Back 16

1 bit memory.

When the clock is 1, the current value of D is stored in the latch.

Front 17

What does a D Flip-Flop do?

Back 17

Used to capture a value on a certain line at a particular instant of time and store it.

State transition occurs when the clock transitions from 0 to 1 (rising edge) or from 1 to 0 (falling edge).

Front 18

The ability of a new machine to execute existing programs without change.

Back 18

Backward Compatibility

Front 19

What is the Instruction Set Architecture?

Back 19

The interface between the hardware and the software.

Front 20

In Von Neumann architecture, you cannot distinguish ________ from ________.

Back 20

instructions from data.

Front 21

Fixed Length Instructions

Back 21

The number of bits used for each instruction is the same.

Front 22

Variable Length Instructions

Back 22

The number of bits used in each instruction may vary.

Front 23

What does CISC stand for?

Back 23

Complex Instruction Set Computing

Front 24

What does RISC stand for?

Back 24

Reduced Instruction Set Computing

Front 25

What two modes do most processors operate in?

Back 25

Kernel mode and User mode

Front 26

Kernel mode

Back 26

Meant for running the operating system.

Allows all instructions including privileged instructions.

Front 27

User mode

Back 27

Intended for running application programs.

Allows only non-privileged instructions to be executed.

Front 28

What happens when a privileged instruction is executed in user mode?

Back 28

A trap (exception) happens, and control is transferred to the operating system.

Front 29

What are some Flag Bits and how are they triggered?

Back 29

N - set when the result of a previous operation was negative.

Z - set when the result of a previous operation was zero.

V - set when the result of a previous operation caused an overflow.

C - set when the result caused a carry out of the leftmost bit.

A - set when there was a carry out of bit 3

P - set when the result had even parity.

Front 30

What register does a Jump (branch) instruction modify?

Back 30

Program Counter (PC)

Front 31

What does a Program Status Word (PSW) typically include?

Back 31

- Condition codes

- Program counter

- Mode bit(s) indicating processor state

- Interrupt masks

Front 32

Segment registers must...

Back 32

point to memory addresses that are multiples of 16. i.e., these addresses will end with four 0's when written in binary.

Front 33

What are the two machine level instructions in hardware to support the stack operation?

Back 33

PUSH and POP

Front 34

List and detail the five zero-address instructions of interest.

Back 34

RET - Return from a procedure; return address is popped off the stack.

IRET - Return from an interrupt handler routine, which pops off the stack the flag register, in addition to the return address.

NOP - You fetch and decode this instruction only to find out that nothing needs to be done during execute phase. Used for inserting delays, especially in pipelined architecture.

HALT - Stop the fetch-decode-execute cycle and shut down.

WAIT - Temporarily suspend the fetch-decode-execute cycle until an interrupt arrives to wake up.

Front 35

What are the two types of printed circuit board?

Back 35

Surface Mounting and Thru'-hole assembly.