《計算機組成及彙編語言原理》學習第 14 天，p178-p199 總結，總計 22 頁。

一、技術總結

1.關於 end 的一點疑問

p178, For example, one instruction (BSWAP) swaps the end bytes in a 32-bit register (specified as an argument), a task that could be performed using basic arithmetic in a dozen or so steps.

BSWAP 的意思是 "Byte SWAP", 作用是“The bswap instruction reverse the byte order of the destination. This instruction is provided for converting little-endian values to big-endian format and vice versa.”。

示例：

bswap eax

假設 EAX 寄存器裏面的值是 0x12345678, 執行 bswap eax 指令後eax 寄存器裏面的值變為 0x78563412。

不是很理解作者為什麼加一個 end 去修飾 bytes——"swaps the end bytes"，加了感覺不好理解。

2.superscalar architecture

superscalar: A method of achieving MIMD parallelism by duplicating pipelines or pipeline stages to enhance performance.

3.Microcontroller

A microcontroller is the kind of computer used for small-scale control operations inside devices that one doesn’t usually think of as being computers.

二、英語總結(生詞：3)

1.to a greater/lesser degree/extent

idiom. used to describe the effect or importance of sth. 示例：This new tax affects the middle class and, to a lesseer extent, the rich。

p179, Unlike other computers, most notably those with the Power architecture, and to a lesser extent the JVM, the Pentium does not require that all of its instructions take the same number of bits.

如果在看到上面這個句子之前知道這個習語(idiom)——to a greater/lesser degree/extent，那麼其實理解這個句子就很容易。因為自己之前沒遇到過，同時習語後面沒有用逗號，剛開始很不理解。

2.tamper

vi. to make changes to sth that you should not(擅自改動，蓄意破壞)。

This approach is also very fast, but has a substantial security weakness in that any memory address, including memory in use by the operating system or by other programs running on the machine, is available to be tampered with.

3.thermostat

(1)thermostat: thermo-("temperature") + -stat("device for stabilizing or regulating")

c. a device that controls the temperature of a system automatically(温度自動調節器，恆温器)。

p185，Classic examples of such devices include traffic lights, toasters, thermostats, and elevators, but better, more detailed types are the microcontrollers that are now installed in modern automobiles.

三、其它

chapter 9簡評：介紹微控制器(microcontroller)的歷史背景、組成、彙編語言的使用，內存組織。這些與當前的編程關係不大，可當做歷史閲讀。

四、參考資料

1. 編程

(1) Patrick Juola，《計算機組成及彙編語言原理》：https://book.douban.com/subject/3069889/

2. 英語

(1) Etymology Dictionary：https://www.etymonline.com

(2) Cambridge Dictionary：https://dictionary.cambridge.org

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