nasm astrspn函数 x86

xxx.asm

%define p1 ebp+8

%define p2 ebp+12

%define p3 ebp+16

section .text

  global dllmain

  export astrspn

dllmain:

  mov eax,1

  ret 12

;---------------------------------------------------;

; 返回不属于一组字符的字符串中第一个字符的索引

;---------------------------------------------------;

astrspn:

  push ebp

  mov ebp,esp

  sub esp,8

  mov edx,[p1]	; const char *str

  mov ecx,[p2]	; const char *strCharSet

  xor eax,eax

  ; 临时变量

  mov [ebp-4],ecx

  mov [ebp-8],ebx

  ;-------------------------------------;

  ; 遍历 str

  ;-------------------------------------;

  .forStr:

  mov bh,[edx]

  test bh,bh

  jz .return

  ;-------------------------------------;

  ; 遍历 strCharSet

  ;-------------------------------------;

  .forStrCharSet:

  mov bl,[ecx]

  test bl,bl

  jz .return	; 没找到退出函数

  cmp bh,bl

  je .forbreak	; 相等 next str

  inc ecx

  jmp .forStrCharSet	; 不相等 next strCharSet

  .forbreak:

  mov ecx,[ebp-4]

  inc edx

  inc eax

  jmp .forStr

  .return:

  mov ebx,[ebp-8]

  add esp,8

  mov esp,ebp

  pop ebp

  ret 8

c++:

#include <iostream>

#include <Windows.h>

typedef int (CALLBACK* astrspn_t)(const char* str, const char* strCharSet);

astrspn_t astrspn;

int main()

{

  HMODULE myDLL = LoadLibraryA("xxx.dll");

  astrspn = (astrspn_t)GetProcAddress(myDLL, "astrspn");

  printf("%d\n", strspn( "abbbc", "ab")); // 4

  printf("%d\n", astrspn("abbbc", "ab")); // 4

  return 0;

}

巴特西

nasm astrspn函数 x86

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