#define ATA_NOP                 0x00
#define ATA_DEV_RESET           0x08
#define ATA_PACKETCMD           0xA0
#define ATA_READ_NATIVE_MAX     0xF8
#define ATA_READ_NATIVE_MAX_EXT 0x27
#define ATA_SET_MAX             0xF9
#define ATA_SET_MAX_EXT         0x37
#define ATA_MULTREAD            0xC4
#define ATA_MULTREAD_EXT        0x29
#define ATA_MULTWRITE           0xC5
#define ATA_MULTWRITE_EXT       0x39
#define ATA_IDENTIFY_DEVICE     0xEC

#define S_ERROR         0x01
#define S_DRQ           0x08
#define S_SEEK          0x10
#define S_DF            0x20
#define S_READY         0x40
#define S_BUSY          0x80

#define ATAR0_DATA      0
#define ATAR0_FEATURE   1
#define ATAR0_NSECTOR   2
#define ATAR0_SECTOR    3
#define ATAR0_LCYL      4
#define ATAR0_HCYL      5
#define ATAR0_SELECT    6
#define ATAR0_STATUS    7
#define ATAR0_CMD       7
#define ATAR1_CONTROL   2