#include <fcntl.h>
#include <io.h>
#include <malloc.h>
#include <stdio.h>
#include <string.h>

#define BASE 0xe1ba3d

static char size[] =
{
    'b', 'w', 'd'
};

#define make_w(ptr) (((ptr)[1] << 8) + (ptr)[0])
#define make_dw(ptr) (((unsigned long) (ptr)[3] << 0x18) + ((unsigned long) (ptr)[2] << 0x10) + ((ptr)[1] << 8) + (ptr)[0])

void main(int argc, char *argv[])
{
    int            f, l;
    unsigned char *b1, *b2;



    printf("Bruit - Disassembler for the Brulez VCPU, by Peter Ferrie 2004\n\n");

    if ((argc != 2)
     || ((f = open(argv[1], O_RDONLY | O_BINARY)) == -1)
       )
    {
        printf("usage: bruit <file>\n");
        return;
    }

    read(f, b1 = b2 = (unsigned char *) malloc(l = filelength(f)), filelength(f));
    close(f);

    do
    {
        unsigned char c;



        printf("%08lx\t", (long) (b1 - b2) + BASE);

        switch (c = *b1++)
        {
            case 0:
            {
                switch (*b1++)
                {
                    case 0:
                    {
                        printf("PUSH\t%08lx\n", make_dw(b1) ^ 0x37195411);
                        b1 += 4;
                        break;
                    }

                    case 1:
                    {
                        printf("PUSH\t%08lx\n", make_dw(b1) + 0xADD01337);
                        b1 += 4;
                        break;
                    }

                    case 2:
                    {
                        printf("PUSH\tR%d\n", *b1++ ^ 0x47);
                        break;
                    }

                    case 3:
                    {
                        printf("POP\tR%d\n", *b1++ ^ 0x66);
                        break;
                    }

                    case 4:
                    {
                        printf("POP\t%d\n", *b1++ ^ 0x45);
                        break;
                    }

                    default:
                    {
                        goto bad_op;
                    }
                }

                break;
            }

            case 1:
            {
                switch (c = *b1++)
                {
                    case 0:
                    case 2:
                    {
                        printf("JMP\tSPECIAL\n");
                        break;
                    }

                    case 1:
                    {
                        printf("EXCPT\n");
                        break;
                    }

                    case 3:
                    {
                        if (b1[1] > 2)
                        {
                            goto bad_op;
                        }

                        printf("XOR\t%c[R%d], R%d\n", size[b1[1]], b1[2], b1[0]);
                        b1 += 3;
                        break;
                    }

                    case 4:
                    {
                        printf("ADD\tR%d, %08lx\n", b1[0] - 3, make_dw(b1 + 1));
                        b1 += 5;
                        break;
                    }

                    case 5:
                    {
                        printf("SUB\tR%d, %08lx\n", b1[0] - 2, make_dw(b1 + 1));
                        b1 += 5;
                        break;
                    }

                    case 6:
                    {
                        printf("AND\tR%d, %08lx\n", b1[0] - 5, make_dw(b1 + 1));
                        b1 += 5;
                        break;
                    }

                    case 7:
                    {
                        printf("OR\tR%d, %08lx\n", b1[0] - 4, make_dw(b1 + 1));
                        b1 += 5;
                        break;
                    }

                    case 8:
                    {
                        printf("XOR\tR%d, %08lx\n", b1[0], make_dw(b1 + 1));
                        b1 += 5;
                        break;
                    }

                    case 9:
                    {
                        printf("ADD\tR%d, R%d\n", b1[1] - 3, b1[2] - 1);
                        b1 += 2;
                        break;
                    }

                    case 0x0a:
                    {
                        printf("CMP\tR%d, R%d\n", b1[1] - 1, b1[2] - 2);
                        b1 += 2;
                        break;
                    }

                    default:
                    {
                        goto bad_op;
                    }
                }

                break;
            }

            case 2:
            {
                switch (c = *b1++)
                {
                    case 0:
                    {
                        printf("EXIT\n");
                        break;
                    }

                    case 1:
                    {
                        printf("CALL\t[%08lx]\n", make_dw(b1) + 0xFEA731DE);
                        b1 += 4;
                        break;
                    }

                    case 2:
                    {
                        printf("MOV\tR%d, %08lx\n", b1[4], make_dw(b1) + 0xAEFDED04);
                        b1 += 5;
                        break;
                    }

                    case 3:
                    {
                        printf("DEC\tR%d\n", *b1++);
                        break;
                    }

                    case 4:
                    {
                        printf("INC\tR%d\n", *b1++);
                        break;
                    }

                    case 5:
                    {
                        printf("AND\tR%d, 0\n", *b1++);
                        break;
                    }

                    case 6:
                    {
                        printf("SCAN\t[R0], %02hx, %04hx\n", b1[0], make_w(b1 + 1));
                        b1 += 3;
                        break;
                    }

                    case 7:
                    {
                        printf("BREAK");
                        break;
                    }

                    case 8:
                    case 0x0a:
                    case 0x0b:
                    {
                        printf("MOV\tR%d, %c[R%d]\n", b1[1], size[((c - 9) & 3) - 1], b1[0]);
                        b1 += 2;
                        break;
                    }

                    case 9:
                    {
                        printf("BSWAP\tR%d\n", *b1++);
                        break;
                    }

                    default:
                    {
                        goto bad_op;
                    }
                }

                break;
            }

            case 3:
            {
                switch (*b1++)
                {
                    case 0:
                    {
                        printf("CMP\tSTK[0], STK[1]\n"
                               "%08lx\t"
                               "JE\t%08lx\n",
                               (long) (b1 - b2) + BASE,
                               make_dw(b1) - 0x31337
                              );
                        b1 += 4;
                        break;
                    }

                    default:
                    {
                        goto bad_op;
                    }
                }

                break;
            }

            case 4:
            {
                switch (*b1++)
                {
                    case 0:
                    {
                        printf("JMP\t%08lx\n", make_dw(b1) + 0x0DEADEAD);
                        b1 += 4;
                        break;
                    }

                    case 1:
                    {
                        printf("JNE\t%08lx\n", make_dw(b1) + 1 + BASE);
                        b1 += 4;
                        break;
                    }

                    case 2:
                    {
                        printf("JE\t%08lx\n", make_dw(b1) + 4 + BASE);
                        b1 += 4;
                        break;
                    }

                    default:
                    {
                        goto bad_op;
                    }
                }

                break;
            }

            case 5:
            {
                switch (*b1++)
                {
                    case 0:
                    {
                        printf("CALL\t%08lx\n", make_dw(b1));
                        b1 += 4;
                        break;
                    }

                    case 1:
                    {
                        printf("RET\n");
                        break;
                    }

                    default:
                    {
                        goto bad_op;
                    }
                }

                break;
            }

            default:
            {
                if ((c >= 0x41)
                 && (c <= 0x5a)
                   )
                {
                    printf("db\t%s\n", b1 - 1);
                    b1 += strlen(b1) + 1;
                }
                else
                {
bad_op:;
                    printf("unsupported opcode (%x)\n", *(b1 - 1));
                }
            }
        }
    }
    while ((long) (b1 - b2) < l);

    printf("%08lx\tEND\n", (long) (b1 - b2) + BASE);
    free(b2);
}