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Cコードで外部ファイルからasm関数を呼び出そうとしています。それはうまく構築されますが、結果は想定どおりではありません。ファイル チェックサムの代わりに、奇妙な文字が表示されます。

    #include <stdio.h>
    #include <stdlib.h>
    #include <sys/stat.h>

    extern "C" unsigned long __stdcall CRC32(size_t sizeOfFile, char buffer[]);


    int fsize(char* file) {
        int size;
        FILE* fh;

        fopen_s(&fh, file, "rb" );
        if(fh != NULL){
            if( fseek(fh, 0, SEEK_END) ){
                fclose(fh);
                return -1;
            }

            size = ftell(fh);
            fclose(fh);
            return size;
        }

        return -1; //error
    }

    void calculateChecksum(char * filename, char * checksum){
        FILE *file = NULL;

        unsigned long crc32;


        char hex[10];
        fopen_s(&file, filename, "rb" );
        size_t size = fsize(filename);
        char *buffer=(char*)malloc(size);
        fread_s(buffer,size,size,1,file);
        crc32=CRC32(size,buffer);
        int n = sprintf_s(hex,"%x",crc32);

        for (int i=0;i<8;i++){
            checksum[i]=hex[i];
        }
        fclose(file);
        file = NULL;
    }




    int main(){
        char checksum[8];
        calculateChecksum("B:\\secretMessageC#.txt",checksum);

        char hex[10];

        for (int i=0;i<8;i++){
            checksum[i]=hex[i];
            printf("%c",checksum[i]);
        }

        getchar();
        return 0;
    }

私の外部アセンバーコード:

    .586
    .model flat, stdcall 
    .xmm
    .data
    .code
    CRC32 proc sizeOfFile:DWORD, file:DWORD
        push    esi
        push    ecx
        push    edx

        mov esi, file
        xor edx, edx
        or  eax, -1
        mov ecx, sizeOfFile

    CRC32_loop:
        mov dl, byte ptr [esi]
        xor dl, al
        shr eax, 8
        xor eax, dword ptr [crc32_table + 4*edx]
        inc esi
        dec ecx
        jnz CRC32_loop

        not eax

        pop edx
        pop ecx
        pop esi
        ret
            CRC32 endp
    crc32_table dd 000000000h, 077073096h, 0EE0E612Ch, 0990951BAh, 0076DC419h, 0706AF48Fh, 0E963A535h, 09E6495A3h, 00EDB8832h, 079DCB8A4h
                dd 0E0D5E91Eh, 097D2D988h, 009B64C2Bh, 07EB17CBDh, 0E7B82D07h, 090BF1D91h, 01DB71064h, 06AB020F2h, 0F3B97148h, 084BE41DEh
                dd 01ADAD47Dh, 06DDDE4EBh, 0F4D4B551h, 083D385C7h, 0136C9856h, 0646BA8C0h, 0FD62F97Ah, 08A65C9ECh, 014015C4Fh, 063066CD9h
                dd 0FA0F3D63h, 08D080DF5h, 03B6E20C8h, 04C69105Eh, 0D56041E4h, 0A2677172h, 03C03E4D1h, 04B04D447h, 0D20D85FDh, 0A50AB56Bh
                dd 035B5A8FAh, 042B2986Ch, 0DBBBC9D6h, 0ACBCF940h, 032D86CE3h, 045DF5C75h, 0DCD60DCFh, 0ABD13D59h, 026D930ACh, 051DE003Ah
                dd 0C8D75180h, 0BFD06116h, 021B4F4B5h, 056B3C423h, 0CFBA9599h, 0B8BDA50Fh, 02802B89Eh, 05F058808h, 0C60CD9B2h, 0B10BE924h
                dd 02F6F7C87h, 058684C11h, 0C1611DABh, 0B6662D3Dh, 076DC4190h, 001DB7106h, 098D220BCh, 0EFD5102Ah, 071B18589h, 006B6B51Fh
                dd 09FBFE4A5h, 0E8B8D433h, 07807C9A2h, 00F00F934h, 09609A88Eh, 0E10E9818h, 07F6A0DBBh, 0086D3D2Dh, 091646C97h, 0E6635C01h
                dd 06B6B51F4h, 01C6C6162h, 0856530D8h, 0F262004Eh, 06C0695EDh, 01B01A57Bh, 08208F4C1h, 0F50FC457h, 065B0D9C6h, 012B7E950h
                dd 08BBEB8EAh, 0FCB9887Ch, 062DD1DDFh, 015DA2D49h, 08CD37CF3h, 0FBD44C65h, 04DB26158h, 03AB551CEh, 0A3BC0074h, 0D4BB30E2h
                dd 04ADFA541h, 03DD895D7h, 0A4D1C46Dh, 0D3D6F4FBh, 04369E96Ah, 0346ED9FCh, 0AD678846h, 0DA60B8D0h, 044042D73h, 033031DE5h 
                dd 0AA0A4C5Fh, 0DD0D7CC9h, 05005713Ch, 0270241AAh, 0BE0B1010h, 0C90C2086h, 05768B525h, 0206F85B3h, 0B966D409h, 0CE61E49Fh
                dd 05EDEF90Eh, 029D9C998h, 0B0D09822h, 0C7D7A8B4h, 059B33D17h, 02EB40D81h, 0B7BD5C3Bh, 0C0BA6CADh, 0EDB88320h, 09ABFB3B6h
                dd 003B6E20Ch, 074B1D29Ah, 0EAD54739h, 09DD277AFh, 004DB2615h, 073DC1683h, 0E3630B12h, 094643B84h, 00D6D6A3Eh, 07A6A5AA8h 
                dd 0E40ECF0Bh, 09309FF9Dh, 00A00AE27h, 07D079EB1h, 0F00F9344h, 08708A3D2h, 01E01F268h, 06906C2FEh, 0F762575Dh, 0806567CBh
                dd 0196C3671h, 06E6B06E7h, 0FED41B76h, 089D32BE0h, 010DA7A5Ah, 067DD4ACCh, 0F9B9DF6Fh, 08EBEEFF9h, 017B7BE43h, 060B08ED5h
                dd 0D6D6A3E8h, 0A1D1937Eh, 038D8C2C4h, 04FDFF252h, 0D1BB67F1h, 0A6BC5767h, 03FB506DDh, 048B2364Bh, 0D80D2BDAh, 0AF0A1B4Ch
                dd 036034AF6h, 041047A60h, 0DF60EFC3h, 0A867DF55h, 0316E8EEFh, 04669BE79h, 0CB61B38Ch, 0BC66831Ah, 0256FD2A0h, 05268E236h
                dd 0CC0C7795h, 0BB0B4703h, 0220216B9h, 05505262Fh, 0C5BA3BBEh, 0B2BD0B28h, 02BB45A92h, 05CB36A04h, 0C2D7FFA7h, 0B5D0CF31h
                dd 02CD99E8Bh, 05BDEAE1Dh, 09B64C2B0h, 0EC63F226h, 0756AA39Ch, 0026D930Ah, 09C0906A9h, 0EB0E363Fh, 072076785h, 005005713h
                dd 095BF4A82h, 0E2B87A14h, 07BB12BAEh, 00CB61B38h, 092D28E9Bh, 0E5D5BE0Dh, 07CDCEFB7h, 00BDBDF21h, 086D3D2D4h, 0F1D4E242h 
                dd 068DDB3F8h, 01FDA836Eh, 081BE16CDh, 0F6B9265Bh, 06FB077E1h, 018B74777h, 088085AE6h, 0FF0F6A70h, 066063BCAh, 011010B5Ch
                dd 08F659EFFh, 0F862AE69h, 0616BFFD3h, 0166CCF45h, 0A00AE278h, 0D70DD2EEh, 04E048354h, 03903B3C2h, 0A7672661h, 0D06016F7h
                dd 04969474Dh, 03E6E77DBh, 0AED16A4Ah, 0D9D65ADCh, 040DF0B66h, 037D83BF0h, 0A9BCAE53h, 0DEBB9EC5h, 047B2CF7Fh, 030B5FFE9h
                dd 0BDBDF21Ch, 0CABAC28Ah, 053B39330h, 024B4A3A6h, 0BAD03605h, 0CDD70693h, 054DE5729h, 023D967BFh, 0B3667A2Eh, 0C4614AB8h
                dd 05D681B02h, 02A6F2B94h, 0B40BBE37h, 0C30C8EA1h, 05A05DF1Bh, 02D02EF8Dh   
    end
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