04.Function_Quiz_01_03

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문제

어셈블리코드

실행 결과

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문제 풀이

00401000              /$  55              PUSH    EBP
00401001              |.  8BEC            MOV     EBP, ESP
00401003              |.  51              PUSH    ECX
00401004              |.  0FBE45 0C       MOVSX   EAX, BYTE PTR SS:[EBP+C]
00401008              |.  8B4D 08         MOV     ECX, DWORD PTR SS:[EBP+8]                ;  04_02_03.<ModuleEntryPoint>
0040100B              |.  03C8            ADD     ECX, EAX
0040100D              |.  894D FC         MOV     DWORD PTR SS:[EBP-4], ECX
00401010              |.  8BE5            MOV     ESP, EBP
00401012              |.  5D              POP     EBP                                      ;  kernel32.7C816D4F
00401013              \.  C3              RETN
00401014              /$  55              PUSH    EBP
00401015              |.  8BEC            MOV     EBP, ESP
00401017              |.  6A 61           PUSH    61                                       ; /Arg2 = 00000061
00401019              |.  6A 0A           PUSH    0A                                       ; |Arg1 = 0000000A
0040101B              |.  E8 E0FFFFFF     CALL    04_02_03.00401000                        ; \04_02_03.00401000
00401020              |.  83C4 08         ADD     ESP, 8
00401023              |.  6A 00           PUSH    0                                        ; /Style = MB_OK|MB_APPLMODAL
00401025              |.  68 30504000     PUSH    04_02_03.00405030                        ; |Title = "ITBANK"
0040102A              |.  68 38504000     PUSH    04_02_03.00405038                        ; |Text = "Failed"
0040102F              |.  6A 00           PUSH    0                                        ; |hOwner = NULL
00401031              |.  FF15 94404000   CALL    DWORD PTR DS:[<&USER32.MessageBoxA>]     ; \MessageBoxA
00401037              |.  6A 00           PUSH    0                                        ; /Style = MB_OK|MB_APPLMODAL
00401039              |.  68 40504000     PUSH    04_02_03.00405040                        ; |Title = "ITBANK"
0040103E              |.  68 48504000     PUSH    04_02_03.00405048                        ; |Text = "Success"
00401043              |.  6A 00           PUSH    0                                        ; |hOwner = NULL
00401045              |.  FF15 94404000   CALL    DWORD PTR DS:[<&USER32.MessageBoxA>]     ; \MessageBoxA
0040104B              |.  33C0            XOR     EAX, EAX
0040104D              |.  5D              POP     EBP                                      ;  kernel32.7C816D4F
0040104E              \.  C2 1000         RETN    10

#include <windows.h>

void method(char n1, int n2)
{
    int result = n2 + n1;
}


int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
    method(0x0A, 0x61);

    MessageBoxA(NULL, "Failed", "ITBANK", MB_OK);
    MessageBoxA(NULL, "Success", "ITBANK", MB_OK);

    return 0;
}

 

여기서는 method 함수의 내부에서 MOVSX 가 존재한다.

형 변환이 발생한 것으로 유추하여 문제를 풀어나가야 한다.