《计算机组成及汇编语言原理》学习第 4 天，p48-p81 总结，总计 34 页。
一、技术总结
1.CISC vs RISC
p49， complex instruction set computing
For example, a complex instruction set computing (CISC) chip may be able to move a large block of data, perhaps a string consisting of several thousand bytes, from one memory location to another without using any of the CPU's internal storage. By contrast, a reduced instruction set computing (RISC) chip might have to move each byte or word into the CPU (from memory) and then back into memory.
2.Assembler
(1)什么是assembler?
A program to convert a source file written in assembly language to an executable file.
(2)jasmin
Jasmin is an assembler for the Java Virtual Machine.
(3)instruction(指令)
In assembly language, a type of statement that translates directly into a machine instruction.
(4)directive(伪指令)
A statement in assembly language [in jasmin, beginning with a period (.)] that does not translate into a machine instruction but instead gives instructions to the assembler itself. The .limit directive is one example.
我之前在看汇编语言相关的书的书的都是每次都很想弄懂 directive 和 instruction 的区别是什么？这本书给了定义。
二、英语总结(生词：6)
1.disaster
(1)disaster: dis-("ill, bad") + astro("star, planet")
Its original meaning was "ill-starred event", reflecting an ancient belief that disasters were caused by unfavorable positions of the stars.
c/u. an event that result in great harm, damage, death, or serious difficulty(灾难)。
p48, Imagine the disaster that would occur if the number 0x05 meant not only "add two numbers" but also "halt the computer"! How could the computer tell which was meant?
2.wiring
u. the system of wires that carry electricity in a building(线路)。
p48, Such a complex instruction set will also require a lot of circuitry to perform the various operations, since every operation might need a different set of wiring and transistors.
3.be tuned to
意为"be optimized for"。
4.twist
c. a complicated situation。
p49, The Java Virtual Machine is an example of a stack-based RISC processor, but with a few twists reflecting the fact that physically it doesn't exist.
5.sub-word
(1)sub-: under, below, smaller than
p51, The sub-word storage types byte, short, and char are also somewhat second-class types.
三、其它
chapter 2简评：偏理论介绍，读了让人容易烦躁。
chapter 3 简评：介绍使用 Jasmin 进行汇编语言编程，相对而言，因为足够熟悉，所以让人读起来更顺畅。
四、参考资料
1. 编程
(1) Patrick Juola，《计算机组成及汇编语言原理》：https://book.douban.com/subject/3069889/
2. 英语
(1) Etymology Dictionary：https://www.etymonline.com
(2) Cambridge Dictionary：https://dictionary.cambridge.org
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