2017年嵌入式系统设计师上午真题卷

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1 单选题 1分

执行下面C语言程序段的结果是（ )。main ( ) {int x=l,a=l,b=l;switch(x) {case 0: b++;case 1: a++;case 2: a++; b++;}printf (”a=%d,b=%d“, a, b);}

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正确答案：B

本题解析：

switch case语句语法，当匹配到了一个case条件，会从该条件开始往下执行其余所有条件语句，不再进行判断，因此这里x=1匹配到了case1,其会执行case1及case2的语句。

2 单选题 1分

软件项目至少应形成功能基线、分配基线和产品基线三类基线。功能基线形成的时机是（ ）。

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正确答案：A

本题解析：

配置管理三个基线：功能基线：在系统分析与软件定义阶段结束时，经过正式批准、签字的系统规格说明书、项目任务书、合同书或协议书中所规定的对待开发软件系统的规格说明。分配基线：在需求分析阶段结束时，经过正式评审和批准的需求规格说明，是最初批准的分配配置标识。产品基线：在综合测试阶段结束时，经过正式评审和批准的有关所开发的软件产品的全部配置项的规格说明，是最终批准产品配置标识。

3 单选题 1分

An operating system also has to be able to service peripheral ( ), such as timers,motors, sensors, communicationdevices, disks, etc. All of those can request the attention of the OS ( ) , i.e. at the time that they want to use the OS, theOS has to make sure it's ready to service the requests. Such a request for attention is called an interrupt. There are twokinds of interrupts: Hardware interrupts and Software interrupts. The result of an inteiTup: is also a triggering of theprocessor, so that it jumps to a ( ) address. Examples of cases where software interrupts appear are perhaps a divide by zero, a memory segmentation fault, etc. So this kind of interrupt is not caused by a hardware event but by a specificmachine language operation code. Many systems have more than one hardware interrupt line, and the hardwaremanufacturer typically assembles all these interrupt lines in an interrupt ( ) . An Interrupt (请作答此空) is a piece of hardware that shields the OS from the electronic details of the interrupt lines, so that interrupts can be queued and none of themgets lost.

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正确答案：C

本题解析：暂无解析

4 单选题 1分

An operating system also has to be able to service peripheral ( ), such as timers,motors, sensors, communicationdevices, disks, etc. All of those can request the attention of the OS ( ) , i.e. at the time that they want to use the OS, theOS has to make sure it's ready to service the requests. Such a request for attention is called an interrupt. There are twokinds of interrupts: Hardware interrupts and Software interrupts. The result of an inteiTup: is also a triggering of theprocessor, so that it jumps to a ( ) address. Examples of cases where software interrupts appear are perhaps a divide by zero, a memory segmentation fault, etc. So this kind of interrupt is not caused by a hardware event but by a specificmachine language operation code. Many systems have more than one hardware interrupt line, and the hardwaremanufacturer typically assembles all these interrupt lines in an interrupt (请作答此空) . An Interrupt ( ) is a piece of hardware that shields the OS from the electronic details of the interrupt lines, so that interrupts can be queued and none of themgets lost.

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正确答案：A

本题解析：暂无解析

5 单选题 1分

An operating system also has to be able to service peripheral ( ), such as timers,motors, sensors, communicationdevices, disks, etc. All of those can request the attention of the OS ( ) , i.e. at the time that they want to use the OS, theOS has to make sure it's ready to service the requests. Such a request for attention is called an interrupt. There are twokinds of interrupts: Hardware interrupts and Software interrupts. The result of an inteiTup: is also a triggering of theprocessor, so that it jumps to a (请作答此空) address. Examples of cases where software interrupts appear are perhaps a divide by zero, a memory segmentation fault, etc. So this kind of interrupt is not caused by a hardware event but by a specificmachine language operation code. Many systems have more than one hardware interrupt line, and the hardwaremanufacturer typically assembles all these interrupt lines in an interrupt ( ) . An Interrupt ( ) is a piece of hardware that shields the OS from the electronic details of the interrupt lines, so that interrupts can be queued and none of themgets lost.

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正确答案：B

本题解析：暂无解析

6 单选题 1分

An operating system also has to be able to service peripheral ( ), such as timers,motors, sensors, communicationdevices, disks, etc. All of those can request the attention of the OS (请作答此空) , i.e. at the time that they want to use the OS, theOS has to make sure it's ready to service the requests. Such a request for attention is called an interrupt. There are twokinds of interrupts: Hardware interrupts and Software interrupts. The result of an inteiTup: is also a triggering of theprocessor, so that it jumps to a ( ) address. Examples of cases where software interrupts appear are perhaps a divide by zero, a memory segmentation fault, etc. So this kind of interrupt is not caused by a hardware event but by a specificmachine language operation code. Many systems have more than one hardware interrupt line, and the hardwaremanufacturer typically assembles all these interrupt lines in an interrupt ( ) . An Interrupt ( ) is a piece of hardware that shields the OS from the electronic details of the interrupt lines, so that interrupts can be queued and none of themgets lost.

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正确答案：B

本题解析：暂无解析

7 单选题 1分

An operating system also has to be able to service peripheral (请作答此空), such as timers,motors, sensors, communicationdevices, disks, etc. All of those can request the attention of the OS ( ) , i.e. at the time that they want to use the OS, theOS has to make sure it's ready to service the requests. Such a request for attention is called an interrupt. There are twokinds of interrupts: Hardware interrupts and Software interrupts. The result of an inteiTup: is also a triggering of theprocessor, so that it jumps to a ( ) address. Examples of cases where software interrupts appear are perhaps a divide by zero, a memory segmentation fault, etc. So this kind of interrupt is not caused by a hardware event but by a specificmachine language operation code. Many systems have more than one hardware interrupt line, and the hardwaremanufacturer typically assembles all these interrupt lines in an interrupt ( ) . An Interrupt ( ) is a piece of hardware that shields the OS from the electronic details of the interrupt lines, so that interrupts can be queued and none of themgets lost.

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正确答案：A

本题解析：暂无解析

8 单选题 1分

以下关于特权指令的叙述中，错误的是（)。

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正确答案：C

本题解析：

特权指令指具有特殊权限的指令，由于这类指令的权限最大，所以如果使用不当，就会破坏系统或其它用户信息。因此为了安全起见，这类指令只能用于操作系统或其它系统软件，而一般不直接提供给用户使用。计算机运行时的状态可以分为系统态(或称管态)和用户态(或称目态)两种。当计算机处于系统态运行时，它可以执行特权指令，而处于用户态运行时，则不能执行特权指令。

9 单选题 1分

以下关于指令执行速度MIPS(MillionInstructionsPerSecond)的叙述中，正确的是()。

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正确答案：D

本题解析：

MIPS是百万条指令每秒，用来描述计算机定点运算速度，一台计算机峰值MIPS是按其指令集中基本指令的执行速度计算的；其平均MIPS，是用其指令使用频度加权各类指令执行速度计算得到的；其基准程序MIPS值是用运行基准程序测得的MIPS值。

10 单选题 1分

某32位计算机Cache容量16KB，Cache块大小16Byte，假设主存与Cache地址映像采用直接映像方式，则主存地址为1234E8F8(十六进制）的单元，装入Cache的地址是()。

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正确答案：C

本题解析：

由题意，cache块大小为16B，也即主存和cache都要分割成16B的块，块内偏移占4位低地址，cache容量16KB，共16KB/16B=1024个块，因此块地址占10位，计算机是32位，因此还剩余32-10-4=18位作为高地址，即主存分区号，那么该地址结构为：18位分区号，10位块号，4位块内偏移；题中采用直接映射，只有每个区块号相同的才能命中，题目考察的是装入cache的地址，那么就是取低14位，无需分区号，将1234E8F8展开为二进制取低14位即可。