x86汇编VS利用它的内存位置实际上得到一个变量值 [英] x86 Assembly Actually get a Variables Value vs using its memory location

问题描述

可能重复：结果
  <一href=\"http://stackoverflow.com/questions/12663971/x86-assembly-move-on-byte-from-on-memory-location-to-another\">x86大会字节移动从内存位置到另一个

好了，basicly我已经在这个问题上花了三天时间。这里就是我认为正在发生的事情，我想如果可能的话摸不着头脑。好了，我pretty很多正在写在大会一操作系统，采用NASM，它运行在保护模式下，并且是32位。现在，我想创建一个简单的字节变量，与104的价值，这是一个H。现在，我想在这个变量移动值，寄存器，我想'斧头'就可以了，然后移动104，内存位置0xB8000。这里是我的code应该做到这一点，是不是，所以我需要一些帮助。谢谢 - 马特

Ok, so basicly I have spent three days on this problem. And here's what I think is happening, and I would like to figure this out, if at all possible. Ok, so I pretty much am writing a Operating System in Assembly, using Nasm, it runs in Protected mode, and is 32 bit. Now I am trying to create a simple One Byte Variable, with the value of 104, which is a 'h'. Now I want to move the value in this variable to, a register, I guess 'ax' would be fine, and then move the 104, to memory location '0xB8000'. Here's my code that should do this, and isn't so I need some help. Thanks - Matt

%ifndef ELF_COMPILATION
use32
org 0x200000
[map all main.map]
%endif
section .data
%ifndef ELF_COMPILATION
MultibootSignature dd 464367618
MultibootFlags dd 65539
MultibootChecksum dd -464433157
MultibootHeaderAddr dd MultibootSignature
MultibootLoadAddr dd MultibootSignature
MultibootLoadEndAddr dd EndCode
MultibootBSSEndAddr dd EndCode
MultibootEntryAddr dd START
%endif
%ifdef ELF_COMPILATION
MultibootSignature dd 464367618
MultibootFlags dd 3
MultibootChecksum dd -464367621
%endif
MultibootGraphicsRuntime_VbeModeInfoAddr dd 2147483647
MultibootGraphicsRuntime_VbeControlInfoAddr dd 2147483647
MultibootGraphicsRuntime_VbeMode dd 2147483647
MultiBootInfo_Memory_High dd 0
MultiBootInfo_Memory_Low dd 0
Var2: db 104
section .text
jmp START
START:
    ;Print out letter out.
    call DisplayMessage
    jmp Halt
DisplayMessage:
    mov ax, Var2
    mov [0xB8000], ax
    ret
Halt:
    jmp Halt
EndCode:

不管怎么说，我问类似这样的东西的问题，也没有运气。我知道大会，在大多数情况下，但我不明白为什么这是行不通的。我只能推测是其推VAR2的内存地址VS斧的实际值。如果是这样的话，我怎么加载从地址到AX 104，并进入0xB8000？谢谢你们。

Anyways, I asked a question to something similar like this and had no luck. I know Assembly, for the most part, but I don't see why this isn't working. All I can figure is its putt Var2's memory address vs the actual value in ax. If this is the case, how do I load 104 from that address into ax, and into 0xB8000? Thanks guys.

差点忘了，我现在用的引导加载器的SysLinux。

Almost forgot, the bootloader I am using is SysLinux.

推荐答案

这样的事情应该工作：

mov ah, Var2
mov edi, 0xb8000
mov [edi], ah

...带寄存器内存引用 [EDI] 而不是内存地址直接使用1字节的寄存器，用于存储数据。

...referencing memory with register [edi] instead of memory address direct and using 1 byte register for data.

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