存儲器間接尋址方式

In this type of addressing mode, first the offset address is calculated, then the memory address is calculated and then the operand form that memory location is fetched. There are following modes which lie under the Data Addressing Mode:

在這種類型的尋址模式下 ，首先計算偏移地址，然后計算內(nèi)存地址，然后獲取內(nèi)存位置的操作數(shù)形式。 數(shù)據(jù)尋址模式下有以下幾種模式 ：

Direct Addressing Mode

直接尋址模式

Base Addressing Mode

基本尋址模式

Base Relative Addressing Mode

基本相對尋址模式

Index Addressing Mode

索引尋址模式

Index relative addressing mode

索引相對尋址模式

Base plus Index Addressing Mode

基本加索引尋址模式

Base relative plus Index Addressing Mode

基本相對加索引尋址模式

1)直接尋址模式 (1) Direct Addressing Mode)

In this addressing mode, the offset is specified within the instructions. What this means is that the offset address is directly stored within square brackets and is not present inside any register.

在這種尋址模式下，偏移量在指令中指定。 這意味著偏移地址直接存儲在方括號中，并且不存在于任何寄存器中。

Example:

例：

MOV AL, [4000H]MOV [1234H], BX

2)基本尋址模式 (2) Base Addressing Mode)

In this addressing mode, the offset address for any operand is stored in the base register BX.

在這種尋址模式下，任何操作數(shù)的偏移地址都存儲在基址寄存器BX中。

Example:

例：

MOV AL, [BX]

3)基本相對尋址模式 (3) Base Relative Addressing Mode)

In this addressing mode also, the offset address is stored within the Base register but the difference is that there is some displacement present with it. This displacement can be either of 8 bits or 16 bits. Hence, the offset address will be equal to the contents of the base register + 8/16 bit displacement.

同樣在這種尋址模式下，偏移地址存儲在基址寄存器中，但不同之處在于偏移量存在。 此位移可以是8位或16位。 因此，偏移地址等于基址寄存器的內(nèi)容+ 8/16位位移。

Example:

例：

MOV AL, [BX + 05H] {here, displacement is of 8 bits}MOV AL, [BX+1243H] {here, displacement is of 16 bits}

4)索引尋址模式 (4) Index Addressing Mode)

In this addressing mode, the offset address is defined in the Index Register. (It should be noted here that the Index registers act as an offset for Data Segment as well.) So, the memory location of the operand is calculated with the help of DS and SI.

在這種尋址模式下，偏移地址在索引寄存器中定義。 (此處應注意，索引寄存器也充當數(shù)據(jù)段的偏移量。)因此，操作數(shù)的存儲位置是借助DS和SI來計算的。

Example:

例：

MOV BL, [SI]MOV [SI], DH

5)索引相對尋址方式 (5) Index relative addressing mode)

In this addressing mode, the offset address is equal to the content of index register plus the 8 or 16-bit displacement. It is important to note here that the displacement in all relative addressing modes is a signed number, i.e. the displacement value can either be a positive or a negative hexadecimal number.

在這種尋址模式下，偏移地址等于索引寄存器的內(nèi)容加上8位或16位位移。 在此重要的是要注意，在所有相對尋址模式下的位移都是有符號數(shù)，即位移值可以是正十六進制數(shù)或負十六進制數(shù)。

Example:

例：

MOV BL, [SI + 07H] {Here, the displacement is of 8 bits}MOV BL, [SI – 3034H] {Here, the displacement is of 16 bits}

6)基本加索引尋址模式 (6) Base plus Index Addressing Mode)

In this addressing Mode, the offset address is calculated by both the base register and the index register. Hence, the offset address will be equal to the content of the base register plus the content of the Index register.

在該尋址模式下，偏移地址由基址寄存器和索引寄存器共同計算。 因此，偏移地址將等于基址寄存器的內(nèi)容加上索引寄存器的內(nèi)容。

Example:

例：

MOV AL, [BX + SI]MOV [BX + SI], CL

7)基本相對加索引尋址模式 (7) Base relative plus Index Addressing Mode)

This addressing mode is almost same to the Base plus Index Addressing mode, but like the other relative addressing modes, the difference is only that this mode has a displacement of 8 or 16 bits.

該尋址模式與“基本加索引尋址”模式幾乎相同，但是與其他相對尋址模式一樣，不同之處僅在于該模式的位移為8位或16位。

Example:

例：

MOV CL, [BX + SI + 0AH] {here, the displacement is of 8 bits} MOV AL, [BX + SI + AE07H] {here, the displacement is of 16 bits}

翻譯自: https://www.includehelp.com/embedded-system/data-memory-addressing-mode-in-8086.aspx

存儲器間接尋址方式

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