C2450 - Ch. 02 Review

Front 1

What are the basic components of a microcomputer?

Back 1

CPU (central processor unit), memory storage unit, i/o devices, data bus, control bus, and address bus

Front 2

What are the components in the CPU?

Back 2

registers, ALU, control unit, and clock

Front 3

What are registers?

Back 3

temporary storage locations for processing

Front 4

What is the purpose of the clock?

Back 4

heartbeat of the system -- to synchronize the internal operations of the CPU with other system components

Front 5

What is the purpose of the control unit?

Back 5

to coordinate the sequencing of steps involved in executing machine instructions

Front 6

What is the purpose of the ALU?

Back 6

to perform arithmetic operations such as addition and subtraction and logical operations such as AND, OR, and NOT

Front 7

what is a bus?

Back 7

a group of parallel wires that transfer data from one part of the computer to another.

Front 8

what are the three types of buses?

Back 8

data bus, control bus, and address bus

Front 9

describe the data bus.

Back 9

transfers instructions and data between the CPU and memory (or CPU and i/o devices). BI-DIRECTIONAL (send & receive)

Front 10

describe the control bus.

Back 10

uses binary signals to synchronize actions of all devices attached to the system. Determines whether the CPU will read or write

Front 11

describe the address bus

Back 11

holds the addresses of instructions and data when the currently executing instruction transfers data between the CPU and memory. UNI-DIRECTIONAL (only sends from CPU)

Front 12

what is the clock?

Back 12

the synchronization of each operation involving the CPU and system bus, pulsing at a constant rate. The clock also triggers events.

Front 13

what is the basic unit of time for machine instructions?

Back 13

a machine cycle (or clock cycle)

Front 14

what is the length of a clock cycle?

Back 14

the time required for one complete clock pulse

Front 15

how is the duration of a clock cycle calculated?

Back 15

1/(clock speed), measured in oscillations per second (Hertz)

Front 16

if read = 0 and write = 1, what is the CPU doing?

Back 16

reading

Front 17

if read = 1 and write = 0, what is the CPU doing?

Back 17

writing

Front 18

if read = 1 and write = 1, what is the CPU doing?

Back 18

wait servicing

Front 19

if read = 0 and write = 0, what is the CPU doing?

Back 19

this is illegal and will never happen!

Front 20

what is the order of the instruction execution cycle?

Back 20

fetch, decode, fetch operands, execute, store output

Front 21

what is the process to read from memory?

Back 21

1. address placed on address bus
2. read line set low (read = 0)
3. CPU waits one cycle for memory to respond
4. read line goes to 1 (read = 1), indicating the data is on the data bus

Front 22

What are the named storage locations inside the CPU?

Back 22

(32-bit:) EAX, EBX, ECX, EDX, EBP, ESP, ESI, EDI, EFLAGS, EIP, (16-bit:) CS, SS, DS, ES, FS, GS

Front 23

Which registers can you access parts of? (8-bit & 16-bit)

Back 23

EAX, EBX, ECX, EDX

Front 24

What is the naming convention for the 8-bit and 16-bit registers for ExX registries?

Back 24

16-bit: xX, 8-bit: xL & xH (H indicating higher and L indicating lower)

Front 25

Which registers can you access the full 32-bit or the lower 16-bit?

Back 25

ESI, EDI, EBP, ESP

Front 26

What is the naming convention for the 16-bit registers for ESI, EDI, EBP, and ESP?

Back 26

the last 2 letters (SI, DI, BP, SP)

Front 27

what do ESP and EBP do?

Back 27

manage the stack

Front 28

what do ESI and EDI do?

Back 28

index addressing

Front 29

to multiply or divide, which registry should be used?

Back 29

EAX

Front 30

which registry is used as a loop counter?

Back 30

ECX

Front 31

what are the purposes of the 16-bit registries: CS, SS, DS, ES, FS, GS?

Back 31

CS: code segment, SS: stack segment, DS: data segment; ES, FS, GS: additional segments

Front 32

what is the purpose of the EIP registry?

Back 32

instruction pointer (points to next set of instructions)

Front 33

what is the purpose of the EFLAGS registry?

Back 33

status and control flags (each flag is a binary bit)

Front 34

a flag is set when it equals what?

Back 34

1

Front 35

a flag is clear (or reset) when it equals what?

Back 35

0

Front 36

When is the carry flag set?

Back 36

(CF) is set when the result of an UNSIGNED arithmetic operation is too large for it into the destination

Front 37

When is the overflow flag set?

Back 37

(OF) is set when the result of a SIGNED arithmetic operation is too large or too small to fit into the destination

Front 38

When is the sign flag set?

Back 38

(SF) is set when the result of an arithmetic or logical operation generates a negative result

Front 39

When is the zero flag set?

Back 39

(ZF) is set when the result of an arithmetic or logical operation generates a result of zero

Front 40

When is the auxillary flag set?

Back 40

(AC) is set when an arithmetic operation causes a carry from bit 3 to bit 4 in an 8-bit operand

Front 41

When is the parity flag set?

Back 41

(PF) is set if the least-significant bye in the result contains an even number of 1 bits. Otherwise, PF is clear (used for error checking when there is a possibility that data might be altered or corrupted)

Front 42

What is indirect addressing?

Back 42

moving the contents (ref by variable) into new location

Front 43

What is direct addressing?

Back 43

moving a value (such as 23h) into new location