// $ATA_PRIMARY_DATA := @intcast(0x1F0)
// $ATA_PRIMARY_ERR := @intcast(0x1F1)
// $ATA_PRIMARY_SECCOUNT := @intcast(0x1F2)
// $ATA_PRIMARY_LBA_LO := @intcast(0x1F3)
// $ATA_PRIMARY_LBA_MID := @intcast(0x1F4)
// $ATA_PRIMARY_LBA_HI := @intcast(0x1F5)
// $ATA_PRIMARY_DRIVE_HEAD := @intcast(0x1F6)
// $ATA_PRIMARY_COMM_REGSTAT := @intcast(0x1F7)
// $ATA_PRIMARY_ALTSTAT_DCR := @intcast(0x3F6)

$ATA_PRIMARY_IO := @intcast(0x1F0)

$ATA_PRIMARY_DEVCTL := @intcast(0x3F6)
$ATA_SECONDARY_DEVCTL := @intcast(0x3F6)

$ATA_REG_STAT := @intcast(0x7)

// // Indicates an error occurred. Send a new command to clear it
// STAT_ERR := 1 << 0
// // Set when the drive has PIO data to transfer, or is ready to accept PIO data.
// STAT_DRQ := 1 << 3
// // Overlapped Mode Service Request.
// STAT_SRV := 1 << 4
// // Drive Fault Error (does not set ERR).
// STAT_DF := 1 << 5
// // Bit is clear when drive is spun down, or after an error. Set otherwise.
// STAT_RDY := 1 << 6
// // Indicates the drive is preparing to send/receive data (wait for it to clear).
// // In case of 'hang' (it never clears), do a software reset.
// STAT_BSY := 1 << 7

$ATA_SR_BSY := 0x80
$ATA_SR_DF := 0x20
$ATA_SR_DRQ := 0x8
$ATA_SR_ERR := 0x1