《计算机组成及汇编语言原理》阅读笔记：p133-p159

《计算机组成及汇编语言原理》学习第 11 天，p133-p159 总结，总计 27 页。

一、技术总结

1.segment

(1)定义

Broadly speaking, a contiguous section of memory. More specifically, a section of memory referenced by one of the segment registers of the 80x86 family.

The memory of the 8088 was divided into segments of 64 Kbytes each.

(2) segment register

CS (code segment): The code segment register is used in conjunction with the IP (instruction pointer) to define the location in memory of the executable machine instructions (the program code).

DS (data segment): The data segment register is used in conjunction with the general-purpose registers AX, BX, CX, and DX to control access to global program data.

SS (stack segment): The stack segment register is used in conjunction with the stack registers (SP and BP) to define stack frames, function parameters, and local variables, as discussed below.

ES (extra segment): The extra segment register is used to hold additional segments—for example, if a program is too large to fit into a single code segment.

2.addressing mode

The way to interpret a bit pattern to define the actual operand for a statement. For example, the bit pattern 0x0001 could refer to the actual constant 1, the first register, the contents of memory location 1, and so forth.

(1)immediate mode

An addressing mode where a bit pattern is interpreted as a constant operand. In direct mode, the bit pattern 0x0001 would be the constant 1.

(2)register mode

An addressing mode where a bit pattern is interpreted as a specific register. In register mode, the bit pattern 0x0001 would be interpreted as the first register.

(3)direct mode

An addressing mode where a bit pattern is interpreted as a location in memory holding the desired operand. In direct mode, the bit pattern 0x0001 would be interpreted as memory location 1.

(4)indirect mode

An addressing mode where a bit pattern is interpreted as a constant operand. In direct mode, the bit pattern 0x0001 would be the constant 1.

(5)index mode

An addressing mode where a bit pattern is interpreted as an offset from a memory address stored in a register.

终于在一本书中看到对寻址模式的定义了，个人觉得这种定义非常棒，摘录给大家也看一看。

二、英语总结(生词：1)

1.legitimate

(1)legitimate: lex-(“law”, legal)

adj. allowed according to law, or reseaonable and accetable。

p132, For simplicity, such address pairs are often written in the form segment:offset, such as 259A:8041. In this scheme, legitimate addresses run from 0x00000 (0000:0000) to 0xFFFFF (F000:FFFF).

2.bewildering

(1)bewilder: be-(“thoroughly”) + wilder(“lead astray, lure into the wilds”)

(2)bewildering: bewildering的现在分词，用作形容词。

adj. confusing and difficult to understand。

p133, The modern computer can be attached to a bewildering array of peripherals, ranging from simple keyboards and monitors through business accessories such as scanners and fax machines through truly unusual specialist devices such as vending machines, toasters, and medical imaging devices.

3.co-opt

(1)co-opt: co-(“together, with”) + optare(“to choose, to select”，参考option)

有时也写作 coopt。vt. to bring sb/sth into a group。

p143, For larger patterns (a 16-bit word or a 32-bit “double,” or even an 80-bit “tbyte,” containing 10 bytes and holding an FPU value), one can co-opt two or more adjacent byte locations.