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Question 1:

问题1：

A string is a collection of characters. Each Character is an of byte length which is stored at successive locations. In the 8086 microprocessor, which characters are considered in the string?

字符串是字符的集合。 每个字符都有一个字节长度，存储在连续的位置。 在8086微处理器中，字符串中应考虑哪些字符？

1. EBCDIC characters

   EBCDIC字符

2. ASCII characters

   ASCII字符

3. A string does not treat characters

   字符串不处理字符

4. None of the above

   以上都不是

Answer: a. ASCII characters

答： ASCII字符

Explanation:

说明：

In the 8086 microprocessor's assembly language, the String is the collection of ASCII characters.

在8086微处理器的汇编语言中，字符串是ASCII字符的集合。

Question 2:

问题2：

While performing any of the MOVE instructions over Strings, i.e. MOVSB, MOBSW or MOVSD, by default, the data is transferred from -

默认情况下，在通过字符串执行任何MOVE指令时，即MOVSB，MOBSW或MOVSD，数据将从-

1. DS:SI to ES:DI

   从DS：SI到ES：DI

2. ES:DI to DS:SI

   ES：DI到DS：SI

3. ES:SI to DS:DI

   ES：SI至DS：DI

4. None of the above

   以上都不是

Answer: a. DS:SI to ES:DI

答： 从DS：SI到ES：DI

Explanation:

说明：

By default, every move instruction transfers data from the address calculated from DS register and contents of SI to the address calculated from ES register the contents of DI, i.e. from DS: SI to ES: DI.

默认情况下，每条移动指令都将数据从DS寄存器计算出的地址和SI的内容传输到DI内容从ES寄存器计算出的地址，即从DS：SI到ES：DI。

Question 3:

问题3：

Which of the following is the correct code for repeating the MOVSB instructions 10 times?

以下哪项是将MOVSB指令重复10次的正确代码？

1. REPEAT MOVSB 10

   重复MOVSB 10

2. REP 10 MOV SB

   REP 10 MOV SB

3. CX=10

   CX = 10

   REP MOVSB

   REP MOVSB

4. None of the above

   以上都不是

Answer: c. CX =10 REP
MOVSB

答：c。 CX = 10代表
MOVSB

Explanation:

说明：

REP instruction repeats the given instruction(s) till CX does not becomes zero, i.e. CX != 0. So, for executing the mentioned instruction 10 times, we need to initialize the CX register with 10.

REP指令重复给定的指令，直到CX不为零，即CX！=0。因此，要执行上述指令10次，我们需要将CX寄存器初始化为10。

Question 4:

问题4：

Which of the following flags gets affected when a compare instruction, i.e. CMPSB, CMPSW or CMPSD is executed?

当执行比较指令(即CMPSB，CMPSW或CMPSD)时，以下哪个标志受影响？

1. Direction Flag (DF)

   方向旗(DF)

2. Trap Flag (TF)

   陷阱标志(TF)

3. Interrupt Flag (IF)

   中断标志(IF)

4. Zero Flag (ZF)

   零标记(ZF)

Answer: d. Zero Flag (ZF)

答案：d。 零标记(ZF)

Explanation:

说明：

Whenever a compare instruction over strings is executed, the status flags are affected. From the mentioned options, only Zero Flag is a status flag. The rest are the Control Flags.

每当执行基于字符串的比较指令时，状态标志都会受到影响。 从上述选项中，只有零标志是状态标志。 其余的是控制标志。

Question 5:

问题5：

At a time, on how many bits can we operate while performing any string operation?

一次，执行任何字符串操作时，我们可以操作多少位？

1. 8 bits

   8位

2. 16 bits

   16位

3. 32 bits

   32位

4. All of the above

   上述所有的

Answer: d. All of the above

答案：d。 上述所有的

Explanation:

说明：

The string operations can be performed either on 1 byte, 2 bytes or 4 bytes at a time. In the string instructions, for example, Move instructions, in MOVSB, 'B' stands for Byte, i.e. 8 bits. Similarly, in MOVSW, 'W' stands for a word, i.e. 16 bits and in MOVSD, 'D' stands for a double word, i.e. 32 bits.

可以一次在1个字节，2个字节或4个字节上执行字符串操作。 在字符串指令中，例如，MOVSB中的移动指令，“ B”代表字节，即8位。 同样，在MOVSW中，“ W”代表一个字，即16位，在MOVSD中，“ D”代表一个双字，即32位。

翻译自: https://www.includehelp.com/embedded-system/mcq-string-manipulation-instructions-in-the-8086-microprocessor.aspx

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