nasm astrlwr_s函数 x86
xxx.asm
%define p1 ebp+8 %define p2 ebp+12 %define p3 ebp+16 section .text global dllmain export astrlwr_s dllmain: mov eax,1 ret 12 ;-----------------------------------------; ; 将字符串转换为小写 ;-----------------------------------------; astrlwr_s: push ebp mov ebp,esp mov eax,[p1] ; str ptr mov ecx,[p2] ; numberOfElements .for: test ecx,ecx jz .return mov dl,[eax] test dl,dl jz .return ;----------------------------------------; ; 如果 < 0x41 next ;----------------------------------------; cmp dl,41h jb .next ;----------------------------------------; ; 如果 > 0x5A next ;----------------------------------------; cmp dl,5Ah ja .next add dl,20h mov [eax],dl .next: dec ecx inc eax jmp .for .return: xor eax,eax mov esp,ebp pop ebp ret 8
c++:
#include <iostream> #include <Windows.h> typedef int (CALLBACK* astrlwr_s_t)(char* str, size_t numberOfElements); astrlwr_s_t astrlwr_s; int main() { HMODULE myDLL = LoadLibraryA("xxx.dll"); astrlwr_s = (astrlwr_s_t)GetProcAddress(myDLL, "astrlwr_s"); char a[10] = "aBcD"; printf("%d, %s\n", _strlwr_s(a, 10), a); // abcd char b[10] = "aBcD"; printf("%d, %s\n", astrlwr_s(b, 10), b); // abcd return 0; }
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