unit1.~cpp

bcb中实现调用汇编完成转换功能,学习如何进行此类调用的基础

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop
#pragma inline

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Button1Click(TObject *Sender)
{
    char orig[100];
    char buff[100];
    int orig_len;
    int buff_len;
    memset(orig,0x00,sizeof(orig));
    memset(buff,0x00,sizeof(buff));
    orig_len=Edit1->Text.Length();
    Label1->Caption=orig_len;
    memcpy(orig,Edit1->Text.data(),Edit1->Text.Length());
/*   单函数成功
    asm{
        pushad
        lea     esi,orig
        lea     edi,buff
        mov     ecx,orig_len
        lea     edx,buff_len
        mov     [edx],ecx
        mov     ecx,0
@again:
        cmp     [edx],ecx
        jz      @over_now
        mov     al,byte ptr[esi+ecx]
        mov     byte ptr[edi+ecx],al
        inc     ecx
        jmp     @again
@over_now:
        popad
    }
*/
    //Sleep(10000);
    memcpy(buff,"ABCD",4);

    // 注意 1.需要pushad和popad保存原来环境
    //      2.由于asm相当于直接加入原有code，所以相当于asm里的代码会被顺序执行
    //        为了不执行到不想被执行的代码，必须自己jmp。例如此例中
    //        执行完popad，如果没有jmp，就会去执行atoA了
    //      3.asm最外层不能有ret，否则就打断原来函数的执行了
    asm{
        pushad
        lea     esi,orig
        lea     edi,buff
        mov     ecx,orig_len
        lea     edx,buff_len

        call    atoA

        popad        
        jmp     @endasm
atoA proc
        push    edx
        mov     edx,0
@again:
        cmp     ecx,edx
        jz      @over_now
        mov     al,byte ptr[esi+edx]
        sub     al,20H
        mov     byte ptr[edi+edx],al
        inc     edx
        jmp     @again
@over_now:
        pop     edx
        mov     [edx],ecx
        ret
endp
@endasm:
    }
    
    Edit2->Text=buff;
    Label2->Caption=buff_len;
    
}
//---------------------------------------------------------------------------