更改绝对字地址的值

Question

如何执行更改绝对字地址值的操作？

假设您在5DAh处有一些值，并且您想要计算该地址上的零个数，或者将值从一个绝对地址移动到另一个绝对地址。怎么能这样做？

Answer 1

简答：你不能

你面前可能有一个技巧问题（没有任何线索，只是我的猜测）。

8086芯片的物理架构没有那条指令。

至于你的两个具体问题......

＆＃34; ...你想要计算该地址上的零个数... ＆＃34;

这有些含糊不清，实际上是如此含糊，以至于我无法理解。

＆＃34; ...将值从一个绝对地址移动到另一个... ＆＃34;

好问题。我们将在32位，no，16和32位中执行此操作。

16位示例

    Push    Si                      ;source index register
    Push    Di                      ;destination index register
    Push    Ax                      ;We'll use this for the transfer

    Lea Si, Where_The_Number_Is_Now ;You'll define this, somehow
    Lea Di, Where_We_Want_It_To_Go  ;You'll define this also, same thing

    Mov Ax, Ds:[Si]                 ;The "Ds:" may or may not be needed, be safe
    Mov Ds:[Di], Ax                 ;Probably do need "Ds:" for this instruction

    Pop Ax                          ;Do pay attention to the reverse order
    Pop Di                          ;...of popping the registers in exact
    Pop Si                          ;...opposite of how they were pushed

                                    ; And you are done

32位示例

    Push    Esi                         ;source index register
    Push    Edi                         ;destination index register
    Push    Eax                         ;We'll use this for the transfer

    Lea Esi, Where_The_Number_Is_Now    ;You'll define this, somehow
    Lea Edi, Where_We_Want_It_To_Go     ;You'll define this also, same thing

    Mov Eax, Ds:[Esi]                   ;The "Ds:" may or may not be needed, be safe
    Mov Ds:[Edi], Eax                   ;Probably do need "Ds:" for this instruction

    Pop Eax                             ;Do pay attention to the reverse order
    Pop Edi                             ;...of popping the registers in exact
    Pop Esi                             ;...opposite of how they were pushed

                                        ; And you are done

Answer 2

要更改绝对字地址的值：

mov             byte ptr [5dah], 0

...或...

mov             word ptr [5dah], 0

---

将值从一个绝对字地址移动到另一个绝对字地址：

mov             al, byte ptr [5dah]
mov             byte ptr [1234h], al

...或...

mov             ax, word ptr [5dah]
mov             word ptr [1234h], ax

---

至于另一个问题，那个询问如何计算该地址上零的数量的问题，你有点模糊。