使用 MASM 将寄存器输出到控制台

发布于 2024-11-29 23:27:56 字数 760 浏览 0 评论 0原文

我有一天开始学习 ASM，并且已经完成了一些教程，甚至成功修改了教程内容以使用 jmp 和 cmp 等而不是 MASM .if 和 .while 宏。

我决定先尝试写一些非常非常简单的东西，然后再继续更高级的教程。我正在编写一个斐波那契数生成器。这是我到目前为止的来源：

.386
.model flat, stdcall

option casemap :none

include \masm32\include\windows.inc
include \masm32\include\kernel32.inc
include \masm32\include\masm32.inc

includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\masm32.lib

.code
start:

  mov eax, 1
  mov ecx, 1

  _a:

    push eax
    add  eax, ecx
    pop  ecx

    ; Jump to _b if there is an overflow on eax

    ; Print Values Here

  jmp _a

  _b:

  push 0
  call ExitProcess

end start

我打算检查 eax/ecx 上的溢出，但现在我只想在屏幕上显示 eax/ecx 的值。

我知道如何从 .data 推送常量字符串的地址并调用 StdOut，这是 hello world 教程中的第一个示例，但这似乎完全不同（？）。

原文

I'm one day into learning ASM and I've done a few tutorials, and even successfully modified the tutorial content to use jmp and cmp, etc instead of the MASM .if and .while macros.

I've decided to try and write something very, very simple to begin with before I continue with more advanced tutorials. I'm writing a Fibonacci number generator. Here is the source I have so far:

.386
.model flat, stdcall

option casemap :none

include \masm32\include\windows.inc
include \masm32\include\kernel32.inc
include \masm32\include\masm32.inc

includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\masm32.lib

.code
start:

  mov eax, 1
  mov ecx, 1

  _a:

    push eax
    add  eax, ecx
    pop  ecx

    ; Jump to _b if there is an overflow on eax

    ; Print Values Here

  jmp _a

  _b:

  push 0
  call ExitProcess

end start

I intend to check for overflows on eax/ecx but right now I'm just interested in displaying the values of eax/ecx on the screen.

I know how to push the address of a constant string from .data and call StdOut which was the first example in the hello world tutorial, but this appears to be quite different (?).

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只有一腔孤勇 2024-12-06 23:27:56

这是微软自己提供的代码

http://support.microsoft.com/kb/85068

请注意，此代码在 16 位系统上输出 AX 寄存器。但你可以明白这个想法，你只需要通过循环每个字符将 AX 值转换为 ASCII 字符。跳过中断部分并使用 StdOut 函数。

 mov dx, 4          ; Loop will print out 4 hex characters.
nexthex:
          push dx            ; Save the loop counter.
          mov cl, 4          ; Rotate register 4 bits.
          rol ax, cl
          push ax            ; Save current value in AX.

          and al, 0Fh        ; Mask off all but 4 lowest bits.
          cmp al, 10         ; Check to see if digit is 0-9.
          jl decimal         ; Digit is 0-9.
          add al, 7          ; Add 7 for Digits A-F.
decimal:
          add al, 30h        ; Add 30h to get ASCII character.

          mov dl, al
          ;Use StdOut to print value of dl
           ;mov ah, 02h        ; Prepare for interrupt.
          ;int 21h            ; Do MS-DOS call to print out value.

          pop ax             ; Restore value to AX.
          pop dx             ; Restore the loop counter.
          dec dx             ; Decrement loop counter.
          jnz nexthex        ; Loop back if there is another character
                             ; to print.

另请参见此处：

http://www.masm32.com/board/index.php?PHPSESSID=fa4590ba57dbaad4bc44088172af0b49&action=printpage;topic=14410.0

There is this code provided by Microsoft itself

http://support.microsoft.com/kb/85068

Note that this code outputs AX register on 16 bit systems. But you can get the idea, you just need to convert AX value into ASCII characters by looping through each character. Skip the interrupts part and use your StdOut function.

 mov dx, 4          ; Loop will print out 4 hex characters.
nexthex:
          push dx            ; Save the loop counter.
          mov cl, 4          ; Rotate register 4 bits.
          rol ax, cl
          push ax            ; Save current value in AX.

          and al, 0Fh        ; Mask off all but 4 lowest bits.
          cmp al, 10         ; Check to see if digit is 0-9.
          jl decimal         ; Digit is 0-9.
          add al, 7          ; Add 7 for Digits A-F.
decimal:
          add al, 30h        ; Add 30h to get ASCII character.

          mov dl, al
          ;Use StdOut to print value of dl
           ;mov ah, 02h        ; Prepare for interrupt.
          ;int 21h            ; Do MS-DOS call to print out value.

          pop ax             ; Restore value to AX.
          pop dx             ; Restore the loop counter.
          dec dx             ; Decrement loop counter.
          jnz nexthex        ; Loop back if there is another character
                             ; to print.

See here as well:

http://www.masm32.com/board/index.php?PHPSESSID=fa4590ba57dbaad4bc44088172af0b49&action=printpage;topic=14410.0

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