Question

Microprocessor 8086 material.

Choose the correct answer.

1- For a (64K x 8) RAM, the number of address lines is: *

17

19

16

15

20

14

18

2-Which of the following instructions requires (BYTE PTR)? *

SHR [500H], 3h

LDS SI, [1000H]

LAHF

PUSH [9AAH]

ADD AX, [800H]

3-Where are the interrupt vectors located in the microprocessor’s memory? *

in the first 64K byte

in the first 1K byte

in the first 256K byte

in the first 1M byte

4-NAND gates can be used instead of 138 decoders to generate CS signals for a memory if : *

each bank in this memory included only one memory device

each bank in this memory included more than one memory device

the memory included only one bank

the memory included more than two banks

5-The mistake in the instruction (IN AL, 3AF0H) is that: *

The destination must be AX

The port number is 16-bits

There is no mistake in the instruction

The port number must be the destination

AL must be the source

6-The input bus cycle of 8086Mp is exactly the same as the memory read bus cycle, with one difference: _ signal is exactly the opposite. *

DEN

BHE

T/R

ALE

A0

M/IO

7-The memory location (00011 H) holds the value of ____ that belongs to the ISR of interrupt 4. *

IP (high byte)

CS (low byte)

CS (high byte)

IP (low byte)

SP (high byte)

SP (low byte)

8-In Assebmly language, every subroutine must end with the instruction: *

EXIT

IRET

RET

END

9- If A0 is a logic 0 and BHE is a logic 1, then : *

no bank is selected

the even memory bank is selected

both memory banks are selected

the odd memory bank is selected

10-Interrupts are special type of ____ instruction. *

jump

call

shift/rotate

ret

xlat

11-In XLAT instruction, one of the following is incorrect: *

In XLAT instruction, the destination must be a 16-bit register

AL is used as a pointer to the created look-up table

XLAT equals adding AL to BX and then moving the contents of DS:BX to AL

The look-up table is previously created and stored starting at DS:BX

12-Which of the following is wrong about the difference between DIV and SHR instructions? *

Unlike DIV, SHR can not provide information about the remainder of division

none of the above is correct

Unlike DIV, SHR can only be used to divide by specific numbers

none of the mentioned is wrong

Unlike SHR, DIV can be used with 32-bit numbers

13-A normal memory write bus cycle of 8086Mp takes _ clock cycles. *

4

5

6

2

3

14-Reading a word from the memory in one memory read cycle is possible if the required memory address is: *

in the stack

odd

even

in the data segment

15-To test bit 0 and bit 4 of (AX) in one step using TEST instruction, the destination and source must be: *

AX, 10h

AX, 12h

AX, AX

AX, 11h

AX, 0Ah

AX, 5h

Answer 1

1. 16 "- because in the given size 64kx8 size 64k represents 2 power 16 where to address this 2 power 16 address lines we require 16 lines to decode.
2. " LAHF " - LAHF instructions are used to load into 32 bit or byte instruction to load and store instructions.
3. " in the first 1k byte" - the interrupt vectors are stores in the first 1024 bytes which us 1k byte.
4. " each bank in this memory included more than one memory device " - here NAND gates are used in place of 138 decoders to point to many memory module.

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