Chapter 18

Question 1

Does push and pop operations always done on word

Answer 1

Yes

Question 2

How many block processing instructions in 8088

Answer 2

There are just 5 block processing instructions in 8088.

Question 3

What is the special prefix that repeats the instruction in hardware

Answer 3

REP prefix

Question 4

What are 5 block processing instructions

Answer 4

The five instructions are STOS, LODS, CMPS, SCAS, and MOVS called store string, load string, compare string, scan string, and move string respectively.

Question 5

When byte is used, which register holds the value

Answer 5

AL

Question 6

When word is used, which register holds the value

Answer 6

AX

Question 7

String instruction can work from start to end of block or from end to start of block

Answer 7

it is bidirectional

Question 8

What is the role of Direction Flag

Answer 8

The direction of movement is controlled with the Direction Flag (DF) in the flags register.

Question 9

cld;

does what

Answer 9

clear direction flag

Question 10

std;

does what

Answer 10

Set direction flag

Question 11

What are the two variants of every instruction

Answer 11

byte

word

Question 12

What is REP

Answer 12

It repeats

Question 13

The prefixes REPE (repeat while equal) and REPNE (repeat while not equal) are used with which instruction

Answer 13

SCAS, CMPS