函数适用于堆栈上的缓冲区，但不适用于 .data 或 .bss 部分? [英] Function works with buffers on the stack but not in .data or .bss sections?

问题描述

我有以下代码:

global _start
extern GetStdHandle, WriteConsoleA ;kernel32.dll

section .data:
    buf times 12 db 0

section .text:
_uint32_to_string:
;void uint32_to_string(uint32_t n, char* buffer)
;buffer: 11 bytes (minimum)
    push ebp
    push ebx
    push esi
    push edi
    mov ebp, esp
    mov ebx, [ebp + 24]
    xor edi, edi
    mov eax, [ebp + 20]
    mov ecx, 10
CREATE_UINTEGER_STRING:
    xor edx, edx
    div ecx
    add dl, '0'
    mov [ebx + edi], dl
    inc edi
    cmp eax, 0
    jne CREATE_UINTEGER_STRING
    xor esi, esi
REVERSE_STRING_UNSIGNED:
    mov ecx, 2
    mov eax, edi
    xor edx, edx
    div ecx
    cmp esi, eax
    jnl REVERSE_UNSIGNED_STRING_END
    mov eax, ebx
    add eax, edi
    sub eax, esi
    dec eax
    mov cl, [ebx + esi]
    mov dl, [eax]
    mov [ebx + esi], dl
    mov [eax], cl
    inc esi
    jmp REVERSE_STRING_UNSIGNED
REVERSE_UNSIGNED_STRING_END:
    mov byte [ebx + edi], 0
    mov esp, ebp
    pop edi
    pop esi
    pop ebx
    pop ebp
    ret

_string_length:
;uint32_t string_length(const char* s)
    push ebp
    mov ebp, esp
    mov ecx, [ebp + 8]
    xor eax, eax
GET_STRLEN:
    cmp byte [ecx + eax], 0
    je END_GET_STRLEN
    inc eax
    jmp GET_STRLEN
END_GET_STRLEN:
    mov esp, ebp
    pop ebp
    ret

_start:
    mov ebp, esp
    mov eax, 235 ;here is the number to be printed
    lea ebx, [buf] ;it works if instead of this line I write:
    ; sub esp, 12
    ; mov ebx, esp
    push ebx
    push eax
    call _uint32_to_string
    add esp, 8
    push ebx
    call _string_length
    add esp, 4
    mov edi, eax
    push dword -11
    call GetStdHandle
    push dword 0
    push dword 0
    push edi
    push ebx
    push eax
    call WriteConsoleA
    mov esp, ebp
    xor eax, eax
    ret

我正在使用这个程序在控制台屏幕上打印一个数字.问题是，如果出于某种原因，我选择将 .data 中分配的缓冲区传递给 _uint32_to_string 函数，则程序会出现运行时错误并以乱码退出代码退出.如果我尝试在 .bss 部分中定义缓冲区，如下所示，NASM 会给我一个警告(如果我运行它，程序仍然以垃圾状态退出):

I am using this program to print a number on the console screen. The problem is that if, for some reason, I choose to pass a buffer allocated in .data to the _uint32_to_string function, the program gives me a runtime error and exits with a gibberish exit code. If I try to define the buffer in the .bss section like the following, NASM gives me a warning (and the program still exits with garbage status if I run it):

section .bss:
    buf resb 12
;error: print_program.asm:5: warning: uninitialised space declared in non-BSS section `.bss:': zeroing

幸运的是，如果我在堆栈上分配缓冲区，程序可以正常工作，打印数字并以状态零退出.

Luckily, if I allocate the buffer on the stack the program works correctly, prints the number and exits with status zero.

谁能帮我理解为什么程序可以使用分配在堆栈上的缓冲区而不是 .data 或 .bss 的缓冲区?

Can anybody please help me understand why the program works with buffers allocated on the stack but not with .data or .bss ones?

P.S:如果重要，这里是我编译代码的方式(平台:Windows 10 32 位):

P.S: If it matters, here is how I compile my code (platform: Windows 10 32-bit):

nasm -f win32 -o print_program.obj print_program.asm
golink print_program.obj /console /entry _start kernel32.dll

推荐答案

所以，感谢@fuz，sections 之后不应该有任何冒号.这意味着 section .data: 应该是 section .data..bss 和 .text 相同.

So, thanks to @fuz, there shouldn't be any colons after the sections. That means section .data: should be section .data. Same for .bss and .text.

这篇关于函数适用于堆栈上的缓冲区，但不适用于 .data 或 .bss 部分?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！