#include<stdio.h>
#include<stdlib.h>

char Register[8][4] = {"eax", "ecx", "edx", "ebx", "esp", "ebp", "esi", "edi"};

int ModRM(unsigned char *b){
    unsigned char Mod = (b[1] >> 6) & 3;
    unsigned char RO = (b[1] >> 3) & 7;
    unsigned char RM = b[1] & 7;
    unsigned long int disp32;
    unsigned char disp8;
    unsigned char SS = (b[2] >> 6) & 3;
    unsigned char Index = (b[2] >> 3) & 7;
    unsigned char Base = b[2] & 7;

    switch(Mod){
    case 0:
        switch(RM){
        case 4:
            disp32 = *(unsigned long int *)&b[3];
            switch(SS){
            case 0:
                printf("%s,[%08X+%s]", Register[RO], disp32, Register[Index]);
                break;
            default:
                printf("%s,[%08X+%s*%02X]", Register[RO], disp32, Register[Index], (1 << SS));
                break;
            }
            return 6;
        case 5:
            disp32 = *(unsigned long int *)&b[2];
            printf("%s,[%08X]", Register[RO], disp32);
            return 5;
        default:
            printf("%s,[%s]", Register[RO], Register[RM]);
            return 1;
        }
        printf("case 0");
        break;
    case 1:
        switch(RM){
        case 4:
            disp8 = b[3];
            switch(SS){
            case 0:
                printf("%s,[ebp+%02X+%s]", Register[RO], disp8, Register[Index]);
                break;
            default:
                printf("%s,[ebp+%02X+%s*%02X]", Register[RO], disp8, Register[Index], (1 << SS));
                break;
            }
            return 3;
        default:
            disp8 = b[2];
            printf("%s,[%s+%02X]", Register[RO], Register[RM], disp8);
            return 2;
        }
        printf("case 1");
        break;
    case 2:
        switch(RM){
        case 4:
            disp32 = *(unsigned long int *)&b[3];
            switch(SS){
            case 0:
                printf("%s,[ebp+%08X+%s]", Register[RO], disp32, Register[Index]);
                break;
            default:
                printf("%s,[ebp+%08X+%s*%02X]", Register[RO], disp32, Register[Index], (1 << SS));
                break;
            }
            return 6;
        default:
            disp32 = *(unsigned long int *)&b[2];
            printf("%s,[%s+%08X]", Register[RO], Register[RM], disp32);
            return 5;
        }
        printf("case 2");
        break;
    case 3:
        printf("%s,%s", Register[RO], Register[RM]);
        return 1;
    }
}


unsigned char b[] = "\xEB\x48\x33\xC0\x03\xC2\x8B\x55\x18\x83\xE8\x08\x8B\x02\xC1\xE8\x08\x33\xC9\x8B\xC8\xC1\xE1\x08\x8B\x4D\x08\x03\x4D\xC8\x33\xD2\x8B\x5D\x08\x8A\x11\x80\xC2\x01\x8B\x4D\x18\x8B\x09\x80\xEA\x01\x33\xCA\x81\xE1\xFF\x00\x00\x00\x83\xF1\x16\x83\xF1\x16\x33\x04\x8D\xAC\xAD\xBC\x01\x8B\x55\x18\x89\x02\xE9\x9C\xFD\xFF\xFF";

int main(){

    for(int i=0; i<70; i++){
        ModRM(&b[i]);
        printf("\n");
    }


    system("pause");
    return 0;
}