home work 1

#include <stdio.h>
typedef unsigned char u8;

static void PrintRegister(u8 regVal, u8 wide)
{
    if (!wide)
    {
        switch (regVal)
        {
            case 0b000: printf("AL"); break;
            case 0b001: printf("CL"); break;
            case 0b010: printf("DL"); break;
            case 0b011: printf("BL"); break;
            case 0b100: printf("AH"); break;
            case 0b101: printf("CH"); break;
            case 0b110: printf("DH"); break;
            case 0b111: printf("BH"); break;
            default: printf("Unexpected regval at line: %d",__LINE__); break;
        }
    } else
    {
        switch (regVal)
        {
            case 0b000: printf("AX"); break;
            case 0b001: printf("CX"); break;
            case 0b010: printf("DX"); break;
            case 0b011: printf("BX"); break;
            case 0b100: printf("SP"); break;
            case 0b101: printf("BP"); break;
            case 0b110: printf("SI"); break;
            case 0b111: printf("DI"); break;
            default: printf("Unexpected regval"); break;
        }
    }
}

int main(int argc, char **argv)
{
    char *fileName = argv[1];

    FILE *file = fopen(fileName, "r");
    if (!file)
    {
        printf("Failed to open file: %s\n", fileName);
    }
    fseek(file, 0, SEEK_END);
    long fileSize = ftell(file);
    fseek(file, 0, SEEK_SET);

    for (int i = 0; i < fileSize; i += 2)
    {
        u8 byte1 = (u8) getc(file);
        u8 byte2 = (u8) getc(file);
        if ((byte1 >> 2) == 0b00100010) // MOV instruction 0b00100010=0x22
        {
            printf("MOV ");
        } else
        {
            printf("unsupported");
        }
        u8 d = (byte1 & 0b00000010) >> 1;
        u8 w = (byte1 & 0b00000001);

        u8 mod = (byte2 >> 6); // Ignored for now
        u8 reg = (byte2 & 0b00111000) >> 3;
        u8 rem = (byte2 & 0b00000111);

        if (d)
        {
            // reg first
            PrintRegister(reg, w);
            printf(",");
            PrintRegister(rem, w);
        } else
        {
            // rem first
            PrintRegister(rem, w);
            printf(",");
            PrintRegister(reg, w);
        }
        printf("\n");
    }
    fclose(file);


    return 0;
}