src/ide.js

import { LOG_DISK } from "./const.js";
import { h } from "./lib.js";
import { dbg_assert, dbg_log } from "./log.js";
import { CMOS_BIOS_DISKTRANSFLAG, CMOS_DISK_DATA, CMOS_DISK_DRIVE1_CYL, CMOS_DISK_DRIVE2_CYL } from "./rtc.js";

// For Types Only
import { CPU } from "./cpu.js";
import { BusConnector } from "./bus.js";

// ATA/ATAPI-6/8 IDE Controller
//
// References
// - [ATA8-ACS]
//   ATA/ATAPI Command Set - 3 (ACS-3) (Rev. 5, Oct. 28, 2013)
//   https://read.seas.harvard.edu/cs161/2019/pdf/ata-atapi-8.pdf
// - [ATA-6]
//   AT Attachment with Packet Interface - 6 (ATA/ATAPI-6) (Rev. 3a; Dec. 14, 2001)
//   https://technion-csl.github.io/ose/readings/hardware/ATA-d1410r3a.pdf
// - [CD-SCSI-2]
//   PROPOSAL FOR CD-ROM IN SCSI-2 (X3T9.2/87) (Rev. 0, Jun. 30, 1987)
//   https://www.t10.org/ftp/x3t9.2/document.87/87-106r0.txt
//   https://www.t10.org/ftp/x3t9.2/document.87/87-106r1.txt (errata to r0)
// - [SAM-3]
//   SCSI Architecture Model - 3 (SAM-3) (Sep. 21, 2004)
//   https://dn790004.ca.archive.org/0/items/SCSISpecificationDocumentsSCSIDocuments/SCSI%20Architecture%20Model/SCSI%20Architecture%20Model%203%20rev%2014.pdf
// - [SPC-3]
//   SCSI Primary Commands - 3 (SPC-3) (July 20, 2008)
//   https://www.t10.org/ftp/t10/document.08/08-309r0.pdf
// - [MMC-3]
//   SCSI Multimedia Commands - 3 (MMC-3) (Rev. 10g, Nov. 12, 2001)
//   https://ia902808.us.archive.org/33/items/mmc3r10g/mmc3r10g.pdf
// - [MMC-2]
//   Packet Commands for C/DVD Devices (1997)
//   https://www.t10.org/ftp/t10/document.97/97-108r0.pdf
// - [BMI-1]
//   Programming Interface for Bus Master IDE Controller, Revision 1.0, 5/16/94
//   https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/u9proj/idems100.pdf
// - [SFF-8020]
//   ATA Packet Interface for CD-ROMs (Rev. 1.2, Feb. 12, 1994)
//   https://dn790009.ca.archive.org/0/items/SCSISpecificationDocumentsATAATAPI/SFF-8020_%20ATA%20Packet%20Interface%20for%20CD-ROMs%20-%20SFF.pdf

const CDROM_SECTOR_SIZE = 2048;
const HD_SECTOR_SIZE = 512;

const BUS_MASTER_BASE = 0xB400;

// Per-channel ATA register offsets, legend:
//   (*1*) Control block register (BAR1/3), else: Command block register (BAR0/2)
// Read-only registers:
const ATA_REG_ERROR      = 0x01;  // Error register, see [ATA-6] 7.9
const ATA_REG_STATUS     = 0x07;  // Status register, see [ATA-6] 7.15
const ATA_REG_ALT_STATUS = 0x00;  // (*1*) Alternate Status register, see [ATA-6] 7.3
// Read-/writable registers:
const ATA_REG_DATA       = 0x00;  // Data register, see [ATA-6] 7.6
const ATA_REG_SECTOR     = 0x02;  // Sector Count register, see [ATA-6] 7.14
const ATA_REG_LBA_LOW    = 0x03;  // LBA Low register, see [ATA-6] 7.12
const ATA_REG_LBA_MID    = 0x04;  // LBA Mid register, see [ATA-6] 7.13
const ATA_REG_LBA_HIGH   = 0x05;  // LBA High register, see [ATA-6] 7.11
const ATA_REG_DEVICE     = 0x06;  // Device register, see [ATA-6] 7.7
// Write-only registers:
const ATA_REG_FEATURES   = 0x01;  // Features register, see [ATA-6] 7.10
const ATA_REG_COMMAND    = 0x07;  // Command register, see [ATA-6] 7.4
const ATA_REG_CONTROL    = 0x00;  // (*1*) Device Control register, see [ATA-6] 7.8

// Per-channel Bus Master IDE register offsets (BAR4), see [BMI-1] 2.0
// these are the primary channel's offsets, add 8 for secondary
const BMI_REG_COMMAND = 0x00;     // Bus Master IDE Command register
const BMI_REG_STATUS = 0x02;      // Bus Master IDE Status register
const BMI_REG_PRDT = 0x04;        // Bus Master IDE PRD Table Address register

// Error register bits:
// All bits except for bit 0x04 are command dependent.
const ATA_ER_ABRT = 0x04;  // Command aborted

// Status register bits:
const ATA_SR_ERR  = 0x01;  // Error (ATA)
const ATA_SR_COND = 0x01;  // Check Condition (ATAPI)
const ATA_SR_SENS = 0x02;  // Sense Available (ATAPI)
const ATA_SR_AERR = 0x04;  // Alignment Error
const ATA_SR_DRQ  = 0x08;  // Data Request
const ATA_SR_DSC  = 0x10;  // Drive Seek Complete / Deferred Write Error
const ATA_SR_DF   = 0x20;  // Device Fault / Stream Error
const ATA_SR_DRDY = 0x40;  // Drive Ready
const ATA_SR_BSY  = 0x80;  // Busy

// Device register bits:
// Bits 0x20/0x80 are obsolete and 0x01/0x02/0x04/0x08/0x40 are command dependent.
const ATA_DR_DEV = 0x10;   // Device select; slave device if set, else master device

// Device Control register bits:
// Bits 0x08/0x10/0x20/0x40 are reserved and bit 0x01 is always zero.
const ATA_CR_NIEN = 0x02;  // Interrupt disable (not Interrupt ENable)
const ATA_CR_SRST = 0x04;  // Software reset
const ATA_CR_HOB = 0x80;   // 48-bit Address feature set

// ATA commands
const ATA_CMD_DEVICE_RESET = 0x08;                    // see [ATA8-ACS] 7.6
const ATA_CMD_EXECUTE_DEVICE_DIAGNOSTIC = 0x90;       // see [ATA8-ACS] 7.9
const ATA_CMD_FLUSH_CACHE = 0xE7;                     // see [ATA8-ACS] 7.10
const ATA_CMD_FLUSH_CACHE_EXT = 0xEA;                 // see [ATA8-ACS] 7.11
const ATA_CMD_GET_MEDIA_STATUS = 0xDA;                // see [ATA-6] 8.14
const ATA_CMD_IDENTIFY_DEVICE = 0xEC;                 // see [ATA8-ACS] 7.12
const ATA_CMD_IDENTIFY_PACKET_DEVICE = 0xA1;          // see [ATA8-ACS] 7.13
const ATA_CMD_IDLE_IMMEDIATE = 0xE1;                  // see [ATA8-ACS] 7.15
const ATA_CMD_INITIALIZE_DEVICE_PARAMETERS = 0x91;    // not mentioned in [ATA-6] or [ATA8-ACS]
const ATA_CMD_MEDIA_LOCK = 0xDE;                      // see [ATA-6] 8.20
const ATA_CMD_NOP = 0x00;                             // see [ATA8-ACS] 7.17
const ATA_CMD_PACKET = 0xA0;                          // see [ATA8-ACS] 7.18
const ATA_CMD_READ_DMA = 0xC8;                        // see [ATA8-ACS] 7.21
const ATA_CMD_READ_DMA_EXT = 0x25;                    // see [ATA8-ACS] 7.22
const ATA_CMD_READ_MULTIPLE = 0x29;                   // see [ATA8-ACS] 7.26
const ATA_CMD_READ_MULTIPLE_EXT = 0xC4;               // see [ATA8-ACS] 7.27
const ATA_CMD_READ_NATIVE_MAX_ADDRESS = 0xF8;         // see [ATA-6] 8.32
const ATA_CMD_READ_NATIVE_MAX_ADDRESS_EXT = 0x27;     // see [ATA-6] 8.33
const ATA_CMD_READ_SECTORS = 0x20;                    // see [ATA8-ACS] 7.28
const ATA_CMD_READ_SECTORS_EXT = 0x24;                // see [ATA8-ACS] 7.29
const ATA_CMD_READ_VERIFY_SECTORS = 0x40;             // see [ATA8-ACS] 7.32
const ATA_CMD_SECURITY_FREEZE_LOCK = 0xF5;            // see [ATA8-ACS] 7.40
const ATA_CMD_SET_FEATURES = 0xEF;                    // see [ATA8-ACS] 7.45
const ATA_CMD_SET_MAX = 0xF9;                         // see [ATA-6] 8.47
const ATA_CMD_SET_MULTIPLE_MODE = 0xC6;               // see [ATA8-ACS] 7.46
const ATA_CMD_STANDBY_IMMEDIATE = 0xE0;               // see [ATA8-ACS] 7.50
const ATA_CMD_WRITE_DMA = 0xCA;                       // see [ATA8-ACS] 7.58
const ATA_CMD_WRITE_DMA_EXT = 0x35;                   // see [ATA8-ACS] 7.59
const ATA_CMD_WRITE_MULTIPLE = 0x39;                  // see [ATA8-ACS] 7.64
const ATA_CMD_WRITE_MULTIPLE_EXT = 0xC5;              // see [ATA8-ACS] 7.65
const ATA_CMD_WRITE_SECTORS = 0x30;                   // see [ATA8-ACS] 7.67
const ATA_CMD_WRITE_SECTORS_EXT = 0x34;               // see [ATA8-ACS] 7.68
const ATA_CMD_10h = 0x10;                             // command obsolete/unknown, see [ATA-6] Table E.2
const ATA_CMD_F0h = 0xF0;                             // vendor-specific

const ATA_CMD_NAME =
{
    [ATA_CMD_DEVICE_RESET]:                 "DEVICE RESET",
    [ATA_CMD_EXECUTE_DEVICE_DIAGNOSTIC]:    "EXECUTE DEVICE DIAGNOSTIC",
    [ATA_CMD_FLUSH_CACHE]:                  "FLUSH CACHE",
    [ATA_CMD_FLUSH_CACHE_EXT]:              "FLUSH CACHE EXT",
    [ATA_CMD_GET_MEDIA_STATUS]:             "GET MEDIA STATUS",
    [ATA_CMD_IDENTIFY_DEVICE]:              "IDENTIFY DEVICE",
    [ATA_CMD_IDENTIFY_PACKET_DEVICE]:       "IDENTIFY PACKET DEVICE",
    [ATA_CMD_IDLE_IMMEDIATE]:               "IDLE IMMEDIATE",
    [ATA_CMD_INITIALIZE_DEVICE_PARAMETERS]: "INITIALIZE DEVICE PARAMETERS",
    [ATA_CMD_MEDIA_LOCK]:                   "MEDIA LOCK",
    [ATA_CMD_NOP]:                          "NOP",
    [ATA_CMD_PACKET]:                       "PACKET",
    [ATA_CMD_READ_DMA]:                     "READ DMA",
    [ATA_CMD_READ_DMA_EXT]:                 "READ DMA EXT",
    [ATA_CMD_READ_MULTIPLE]:                "READ MULTIPLE",
    [ATA_CMD_READ_MULTIPLE_EXT]:            "READ MULTIPLE EXT",
    [ATA_CMD_READ_NATIVE_MAX_ADDRESS]:      "READ NATIVE MAX ADDRESS",
    [ATA_CMD_READ_NATIVE_MAX_ADDRESS_EXT]:  "READ NATIVE MAX ADDRESS EXT",
    [ATA_CMD_READ_SECTORS]:                 "READ SECTORS",
    [ATA_CMD_READ_SECTORS_EXT]:             "READ SECTORS EXT",
    [ATA_CMD_READ_VERIFY_SECTORS]:          "READ VERIFY SECTORS",
    [ATA_CMD_SECURITY_FREEZE_LOCK]:         "SECURITY FREEZE LOCK",
    [ATA_CMD_SET_FEATURES]:                 "SET FEATURES",
    [ATA_CMD_SET_MAX]:                      "SET MAX",
    [ATA_CMD_SET_MULTIPLE_MODE]:            "SET MULTIPLE MODE",
    [ATA_CMD_STANDBY_IMMEDIATE]:            "STANDBY IMMEDIATE",
    [ATA_CMD_WRITE_DMA]:                    "WRITE DMA",
    [ATA_CMD_WRITE_DMA_EXT]:                "WRITE DMA EXT",
    [ATA_CMD_WRITE_MULTIPLE]:               "WRITE MULTIPLE",
    [ATA_CMD_WRITE_MULTIPLE_EXT]:           "WRITE MULTIPLE EXT",
    [ATA_CMD_WRITE_SECTORS]:                "WRITE SECTORS",
    [ATA_CMD_WRITE_SECTORS_EXT]:            "WRITE SECTORS EXT",
    [ATA_CMD_10h]:                          "<UNKNOWN 10h>",
    [ATA_CMD_F0h]:                          "<VENDOR-SPECIFIC F0h>",
};

// ATAPI (SCSI-2/MMC-2) commands
const ATAPI_CMD_GET_CONFIGURATION = 0x46;             // see [CD-SCSI-2]
const ATAPI_CMD_GET_EVENT_STATUS_NOTIFICATION = 0x4A; // see [MMC-2] 9.1.2
const ATAPI_CMD_INQUIRY = 0x12;                       // see [MMC-2] 9.1.3
const ATAPI_CMD_MECHANISM_STATUS = 0xBD;              // see [MMC-2] 9.1.5
const ATAPI_CMD_MODE_SENSE_6 = 0x1A;                  // see [CD-SCSI-2]
const ATAPI_CMD_MODE_SENSE_10 = 0x5A;                 // see [MMC-2] 9.1.7
const ATAPI_CMD_PAUSE = 0x45;                         // see [CD-SCSI-2]
const ATAPI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL = 0x1E;  // see [MMC-2] 9.1.9
const ATAPI_CMD_READ_10 = 0x28;                       // see [CD-SCSI-2]
const ATAPI_CMD_READ_12 = 0xA8;                       // see [SFF-8020] 9.8.14
const ATAPI_CMD_READ_CAPACITY = 0x25;                 // see [MMC-2] 9.1.12
const ATAPI_CMD_READ_CD = 0xBE;                       // see [CD-SCSI-2]
const ATAPI_CMD_READ_DISK_INFORMATION = 0x51;         // see [CD-SCSI-2]
const ATAPI_CMD_READ_SUBCHANNEL = 0x42;               // see [CD-SCSI-2]
const ATAPI_CMD_READ_TOC_PMA_ATIP = 0x43;             // see [CD-SCSI-2]
const ATAPI_CMD_READ_TRACK_INFORMATION = 0x52;        // see [CD-SCSI-2]
const ATAPI_CMD_REQUEST_SENSE = 0x03;                 // see [MMC-2] 9.1.18
const ATAPI_CMD_START_STOP_UNIT = 0x1B;               // see [CD-SCSI-2]
const ATAPI_CMD_TEST_UNIT_READY = 0x00;               // see [MMC-2] 9.1.20

// ATAPI command flags
const ATAPI_CF_NONE = 0x00;         // no flags
const ATAPI_CF_NEEDS_DISK = 0x01;   // command needs inserted disk
const ATAPI_CF_UNIT_ATTN = 0x02;    // bounce command if unit attention condition is active

// ATAPI commands, for flags see [MMC-3] 4.2.6
const ATAPI_CMD =
{
    [ATAPI_CMD_GET_CONFIGURATION]:             {name: "GET CONFIGURATION",             flags: ATAPI_CF_NONE},
    [ATAPI_CMD_GET_EVENT_STATUS_NOTIFICATION]: {name: "GET EVENT STATUS NOTIFICATION", flags: ATAPI_CF_NONE},
    [ATAPI_CMD_INQUIRY]:                       {name: "INQUIRY",                       flags: ATAPI_CF_NONE},
    [ATAPI_CMD_MECHANISM_STATUS]:              {name: "MECHANISM STATUS",              flags: ATAPI_CF_NONE},
    [ATAPI_CMD_MODE_SENSE_6]:                  {name: "MODE SENSE (6)",                flags: ATAPI_CF_NONE},
    [ATAPI_CMD_MODE_SENSE_10]:                 {name: "MODE SENSE (10)",               flags: ATAPI_CF_NONE},
    [ATAPI_CMD_PAUSE]:                         {name: "PAUSE",                         flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL]:  {name: "PREVENT ALLOW MEDIUM REMOVAL",  flags: ATAPI_CF_NONE},
    [ATAPI_CMD_READ_10]:                       {name: "READ (10)",                     flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_READ_12]:                       {name: "READ (12)",                     flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_READ_CAPACITY]:                 {name: "READ CAPACITY",                 flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_READ_CD]:                       {name: "READ CD",                       flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_READ_DISK_INFORMATION]:         {name: "READ DISK INFORMATION",         flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_READ_SUBCHANNEL]:               {name: "READ SUBCHANNEL",               flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_READ_TOC_PMA_ATIP]:             {name: "READ TOC PMA ATIP",             flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_READ_TRACK_INFORMATION]:        {name: "READ TRACK INFORMATION",        flags: ATAPI_CF_NEEDS_DISK},
    [ATAPI_CMD_REQUEST_SENSE]:                 {name: "REQUEST SENSE",                 flags: ATAPI_CF_NONE},
    [ATAPI_CMD_START_STOP_UNIT]:               {name: "START STOP UNIT",               flags: ATAPI_CF_NONE},
    [ATAPI_CMD_TEST_UNIT_READY]:               {name: "TEST UNIT READY",               flags: ATAPI_CF_NEEDS_DISK},
};

// ATAPI device signature
const ATAPI_SIGNATURE_LO = 0x14;
const ATAPI_SIGNATURE_HI = 0xEB;

// ATAPI 4-bit Sense Keys, see [MMC-2] 9.1.18.3, Table 123
const ATAPI_SK_NO_SENSE = 0;
const ATAPI_SK_RECOVERED_ERROR = 1;
const ATAPI_SK_NOT_READY = 2;
const ATAPI_SK_MEDIUM_ERROR = 3;
const ATAPI_SK_HARDWARE_ERROR = 4;
const ATAPI_SK_ILLEGAL_REQUEST = 5;
const ATAPI_SK_UNIT_ATTENTION = 6;
const ATAPI_SK_DATA_PROTECT = 7;
const ATAPI_SK_BLANK_CHECK = 8;
const ATAPI_SK_ABORTED_COMMAND = 11;

// ATAPI 8-bit Additional Sense Codes, see [MMC-2] 9.1.18.3, Table 124
// https://github.com/qemu/qemu/blob/3c5a5e213e5f08fbfe70728237f7799ac70f5b99/hw/ide/ide-internal.h#L288
const ATAPI_ASC_INV_FIELD_IN_CMD_PACKET = 0x24;
const ATAPI_ASC_MEDIUM_MAY_HAVE_CHANGED = 0x28;
const ATAPI_ASC_MEDIUM_NOT_PRESENT = 0x3A;

// Debug log detail bits (internal to this module)
const LOG_DETAIL_NONE = 0x00;   // disable debug logging of details
const LOG_DETAIL_REG_IO = 0x01; // log register read/write access
const LOG_DETAIL_IRQ = 0x02;    // log IRQ raise/lower events
const LOG_DETAIL_RW = 0x04;     // log data read/write-related events
const LOG_DETAIL_RW_DMA = 0x08; // log DMA data read/write-related events
const LOG_DETAIL_CHS = 0x10;    // log register-CHS to LBA conversions
const LOG_DETAIL_ALL = 0xFF;    // log all details
// the bitset of active log details (should be 0 when not in DEBUG mode)
const LOG_DETAILS = DEBUG ? LOG_DETAIL_NONE : 0;

/**
 * @constructor
 * @param {CPU} cpu
 * @param {BusConnector} bus
 *
 * ide_config: [ [primary-master, primary-slave], [secondary-master, secondary-slave] ]
 *
 *   Each of the four arguments (primary-master, primary-slave, ...) is either
 *   undefined or an object of the form:
 *
 *       { buffer: Uint8Array, is_cdrom: bool }
 *
 *   If is_cdrom is defined and true:
 *   - If buffer is defined: create an ATAPI CD-ROM device using buffer as inserted disk
 *   - If buffer is undefined: create an ATAPI CD-ROM device with ejectd disk
 *   If is_cdrom is undefined or false:
 *   - If buffer is defined: create an ATA Hard-Disk device using buffer as disk image
 *   - If buffer is undefined: represents a missing device
 *
 *   A slave drive can only exist if a master drive also exists.
 * */
export function IDEController(cpu, bus, ide_config)
{
    this.cpu = cpu;
    this.bus = bus;

    this.primary = undefined;
    this.secondary = undefined;

    const has_primary = ide_config && ide_config[0][0];
    const has_secondary = ide_config && ide_config[1][0];
    if(has_primary || has_secondary)
    {
        if(has_primary)
        {
            this.primary = new IDEChannel(this, 0, ide_config[0], 0x1F0, 0x3F6, 14);
        }
        if(has_secondary)
        {
            this.secondary = new IDEChannel(this, 1, ide_config[1], 0x170, 0x376, 15);
        }

        const vendor_id = 0x8086;    // Intel Corporation
        const device_id = 0x7010;    // 82371SB PIIX3 IDE [Natoma/Triton II]
        const class_code = 0x01;     // Mass Storage Controller
        const subclass = 0x01;       // IDE Controller
        const prog_if = 0x80;        // ISA Compatibility mode-only controller, supports bus mastering
        const interrupt_line = 0x00; // IRQs 14 and 15 are predefined in Compatibility mode and this field is ignored
        const command_base0 = has_primary ? this.primary.command_base : 0;
        const control_base0 = has_primary ? this.primary.control_base : 0;
        const command_base1 = has_secondary ? this.secondary.command_base : 0;
        const control_base1 = has_secondary ? this.secondary.control_base : 0;

        this.name = "ide";
        this.pci_id = 0x1E << 3;
        this.pci_space = [
            vendor_id & 0xFF, vendor_id >> 8, device_id & 0xFF, device_id >> 8, 0x05, 0x00, 0xA0, 0x02,
            0x00, prog_if, subclass, class_code, 0x00, 0x00, 0x00, 0x00,
            command_base0 & 0xFF   | 1, command_base0 >> 8,   0x00, 0x00,
            control_base0 & 0xFF   | 1, control_base0 >> 8,   0x00, 0x00,
            command_base1 & 0xFF   | 1, command_base1 >> 8,   0x00, 0x00,
            control_base1 & 0xFF   | 1, control_base1 >> 8,   0x00, 0x00,
            BUS_MASTER_BASE & 0xFF | 1, BUS_MASTER_BASE >> 8, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x43, 0x10, 0xD4, 0x82,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, interrupt_line, 0x01, 0x00, 0x00,
            // 0x40
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            // 0x80
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        ];
        this.pci_bars = [
            has_primary ? { size: 8 } : undefined,   // BAR0: Command block register address of primary channel
            has_primary ? { size: 1 } : undefined,   // BAR1: Control block register address of primary channel
            has_secondary ? { size: 8 } : undefined, // BAR2: Command block register address of secondary channel
            has_secondary ? { size: 1 } : undefined, // BAR3: Control block register address of secondary channel
            { size: 16 }                             // BAR4: Bus Master I/O register address of both channels (8+8)
        ];
        cpu.devices.pci.register_device(this);
    }

    Object.seal(this);
}

IDEController.prototype.get_state = function()
{
    const state = [];
    state[0] = this.primary;
    state[1] = this.secondary;
    return state;
};

IDEController.prototype.set_state = function(state)
{
    this.primary && this.primary.set_state(state[0]);
    this.secondary && this.secondary.set_state(state[1]);
};

/**
 * @constructor
 * @param {IDEController} controller
 * @param {number} channel_nr
 * */
function IDEChannel(controller, channel_nr, channel_config, command_base, control_base, irq)
{
    this.controller = controller;
    this.channel_nr = channel_nr;
    this.cpu = controller.cpu;
    this.bus = controller.bus;
    this.command_base = command_base;
    this.control_base = control_base;
    this.irq = irq;
    this.name = "ide" + channel_nr;

    const master_cfg = channel_config ? channel_config[0] : undefined;
    const slave_cfg = channel_config ? channel_config[1] : undefined;
    this.master = new IDEInterface(this, 0, master_cfg?.buffer, master_cfg?.is_cdrom);
    this.slave = new IDEInterface(this, 1, slave_cfg?.buffer, slave_cfg?.is_cdrom);

    this.current_interface = this.master;

    /** @type {number} */
    this.device_control_reg = ATA_CR_NIEN;

    /** @type {number} */
    this.prdt_addr = 0;

    /** @type {number} */
    this.dma_status = 0;

    /** @type {number} */
    this.dma_command = 0;

    const cpu = controller.cpu;

    //
    // Command Block Registers: command_base + 0...7 (BAR0: 1F0h, BAR2: 170h)
    //

    cpu.io.register_read(this.command_base | ATA_REG_DATA, this, function()
    {
        return this.current_interface.read_data(1);
    }, function()
    {
        return this.current_interface.read_data(2);
    }, function()
    {
        return this.current_interface.read_data(4);
    });

    cpu.io.register_read(this.command_base | ATA_REG_ERROR, this, function()
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": read Error register: " +
                h(this.current_interface.error_reg & 0xFF), LOG_DISK);
        }
        return this.current_interface.error_reg & 0xFF;
    });

    cpu.io.register_read(this.command_base | ATA_REG_SECTOR, this, function()
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": read Sector Count register: " +
                h(this.current_interface.sector_count_reg & 0xFF), LOG_DISK);
        }
        return this.current_interface.sector_count_reg & 0xFF;
    });

    cpu.io.register_read(this.command_base | ATA_REG_LBA_LOW, this, function()
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": read LBA Low register: " +
                h(this.current_interface.lba_low_reg & 0xFF), LOG_DISK);
        }
        return this.current_interface.lba_low_reg & 0xFF;
    });

    cpu.io.register_read(this.command_base | ATA_REG_LBA_MID, this, function()
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": read LBA Mid register: " +
                h(this.current_interface.lba_mid_reg & 0xFF), LOG_DISK);
        }
        return this.current_interface.lba_mid_reg & 0xFF;
    });

    cpu.io.register_read(this.command_base | ATA_REG_LBA_HIGH, this, function()
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": read LBA High register: " +
                h(this.current_interface.lba_high_reg & 0xFF), LOG_DISK);
        }
        return this.current_interface.lba_high_reg & 0xFF;
    });

    cpu.io.register_read(this.command_base | ATA_REG_DEVICE, this, function()
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": read Device register", LOG_DISK);
        }
        return this.current_interface.device_reg & 0xFF;
    });

    cpu.io.register_read(this.command_base | ATA_REG_STATUS, this, function()
    {
        const status = this.read_status();
        if(LOG_DETAILS & (LOG_DETAIL_REG_IO | LOG_DETAIL_IRQ))
        {
            dbg_log(`${this.current_interface.name}: read Status register: ${h(status, 2)} (lower IRQ ${this.irq})`, LOG_DISK);
        }
        this.cpu.device_lower_irq(this.irq);
        return status;
    });

    cpu.io.register_write(this.command_base | ATA_REG_DATA, this, function(data)
    {
        this.current_interface.write_data_port8(data);
    }, function(data)
    {
        this.current_interface.write_data_port16(data);
    }, function(data)
    {
        this.current_interface.write_data_port32(data);
    });

    cpu.io.register_write(this.command_base | ATA_REG_FEATURES, this, function(data)
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": write Features register: " + h(data), LOG_DISK);
        }
        this.current_interface.features_reg = (this.current_interface.features_reg << 8 | data) & 0xFFFF;
    });

    cpu.io.register_write(this.command_base | ATA_REG_SECTOR, this, function(data)
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": write Sector Count register: " + h(data), LOG_DISK);
        }
        this.current_interface.sector_count_reg = (this.current_interface.sector_count_reg << 8 | data) & 0xFFFF;
    });

    cpu.io.register_write(this.command_base | ATA_REG_LBA_LOW, this, function(data)
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": write LBA Low register: " + h(data), LOG_DISK);
        }
        this.current_interface.lba_low_reg = (this.current_interface.lba_low_reg << 8 | data) & 0xFFFF;
    });

    cpu.io.register_write(this.command_base | ATA_REG_LBA_MID, this, function(data)
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": write LBA Mid register: " + h(data), LOG_DISK);
        }
        this.current_interface.lba_mid_reg = (this.current_interface.lba_mid_reg << 8 | data) & 0xFFFF;
    });

    cpu.io.register_write(this.command_base | ATA_REG_LBA_HIGH, this, function(data)
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": write LBA High register: " + h(data), LOG_DISK);
        }
        this.current_interface.lba_high_reg = (this.current_interface.lba_high_reg << 8 | data) & 0xFFFF;
    });

    cpu.io.register_write(this.command_base | ATA_REG_DEVICE, this, function(data)
    {
        const select_slave = data & ATA_DR_DEV;
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": write Device register: " + h(data, 2), LOG_DISK);
        }
        if((select_slave && this.current_interface === this.master) || (!select_slave && this.current_interface === this.slave))
        {
            if(select_slave)
            {
                dbg_log(`${this.current_interface.name}: select slave device (${this.channel_nr ? "secondary" : "primary"})`, LOG_DISK);
                this.current_interface = this.slave;
            }
            else
            {
                dbg_log(`${this.current_interface.name}: select master device (${this.channel_nr ? "secondary" : "primary"})`, LOG_DISK);
                this.current_interface = this.master;
            }
        }
        this.current_interface.device_reg = data;
        this.current_interface.is_lba = data >> 6 & 1; // TODO: where does this definition of bit 6 come from? not in [ATA-6] or [ATA-4]!
        this.current_interface.head = data & 0xF;      // TODO: same for lower nibble?
    });

    cpu.io.register_write(this.command_base | ATA_REG_COMMAND, this, function(data)
    {
        if(LOG_DETAILS & LOG_DETAIL_REG_IO)
        {
            dbg_log(this.current_interface.name + ": write Command register", LOG_DISK);
        }
        this.current_interface.status_reg &= ~(ATA_SR_ERR|ATA_SR_DF);
        this.current_interface.ata_command(data);
        if(LOG_DETAILS & LOG_DETAIL_IRQ)
        {
            dbg_log(this.current_interface.name + ": lower IRQ " + this.irq, LOG_DISK);
        }
        this.cpu.device_lower_irq(this.irq);
    });

    //
    // Control Block Register: control_base (BAR1: 3F6h, BAR3: 376h)
    //

    // read Alternate Status register
    cpu.io.register_read(this.control_base | ATA_REG_ALT_STATUS, this, this.read_status);

    // write Device Control register
    cpu.io.register_write(this.control_base | ATA_REG_CONTROL, this, this.write_control);

    //
    // Bus Master Registers: bus_master_base + 0...15 (BAR4: B400h)
    // primary channel: bus_master_base + 0...7, secondary: bus_master_base + 8...15
    //

    const bus_master_base = BUS_MASTER_BASE + channel_nr * 8;

    // read/write Bus Master IDE Command register
    cpu.io.register_read(bus_master_base | BMI_REG_COMMAND,
        this, this.dma_read_command8, undefined, this.dma_read_command);
    cpu.io.register_write(bus_master_base | BMI_REG_COMMAND,
        this, this.dma_write_command8, undefined, this.dma_write_command);

    // read/write Bus Master IDE Status register
    cpu.io.register_read(bus_master_base | BMI_REG_STATUS,
        this, this.dma_read_status);
    cpu.io.register_write(bus_master_base | BMI_REG_STATUS,
        this, this.dma_write_status);

    // read/write Bus Master IDE PRD Table Address register
    cpu.io.register_read(bus_master_base | BMI_REG_PRDT,
        this, undefined, undefined, this.dma_read_addr);
    cpu.io.register_write(bus_master_base | BMI_REG_PRDT,
        this, undefined, undefined, this.dma_set_addr);

    DEBUG && Object.seal(this);
}

IDEChannel.prototype.read_status = function()
{
    return this.current_interface.drive_connected ? this.current_interface.status_reg : 0;
};

IDEChannel.prototype.write_control = function(data)
{
    if(LOG_DETAILS & (LOG_DETAIL_REG_IO | LOG_DETAIL_IRQ))
    {
        dbg_log(this.current_interface.name + ": write Device Control register: " +
            h(data, 2) + " interrupts " + ((data & ATA_CR_NIEN) ? "disabled" : "enabled"), LOG_DISK);
    }
    if(data & ATA_CR_SRST)
    {
        dbg_log(`${this.current_interface.name}: soft reset via control port (lower IRQ ${this.irq})`, LOG_DISK);
        this.cpu.device_lower_irq(this.irq);
        this.master.device_reset();
        this.slave.device_reset();
    }
    this.device_control_reg = data;
};

IDEChannel.prototype.dma_read_addr = function()
{
    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.current_interface.name + ": DMA get address: " + h(this.prdt_addr, 8), LOG_DISK);
    }
    return this.prdt_addr;
};

IDEChannel.prototype.dma_set_addr = function(data)
{
    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.current_interface.name + ": DMA set address: " + h(data, 8), LOG_DISK);
    }
    this.prdt_addr = data;
};

IDEChannel.prototype.dma_read_status = function()
{
    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.current_interface.name + ": DMA read status: " + h(this.dma_status), LOG_DISK);
    }
    return this.dma_status;
};

IDEChannel.prototype.dma_write_status = function(value)
{
    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.current_interface.name + ": DMA write status: " + h(value), LOG_DISK);
    }
    this.dma_status &= ~(value & 6);
};

IDEChannel.prototype.dma_read_command = function()
{
    return this.dma_read_command8() | this.dma_read_status() << 16;
};

IDEChannel.prototype.dma_read_command8 = function()
{
    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.current_interface.name + ": DMA read command: " + h(this.dma_command), LOG_DISK);
    }
    return this.dma_command;
};

IDEChannel.prototype.dma_write_command = function(value)
{
    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.current_interface.name + ": DMA write command: " + h(value), LOG_DISK);
    }
    this.dma_write_command8(value & 0xFF);
    this.dma_write_status(value >> 16 & 0xFF);
};

IDEChannel.prototype.dma_write_command8 = function(value)
{
    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.current_interface.name + ": DMA write command8: " + h(value), LOG_DISK);
    }

    const old_command = this.dma_command;
    this.dma_command = value & 0x09;

    if((old_command & 1) === (value & 1))
    {
        return;
    }

    if((value & 1) === 0)
    {
        this.dma_status &= ~1;
        return;
    }

    this.dma_status |= 1;

    switch(this.current_interface.current_command)
    {
        case ATA_CMD_READ_DMA:
        case ATA_CMD_READ_DMA_EXT:
            this.current_interface.do_ata_read_sectors_dma();
            break;
        case ATA_CMD_WRITE_DMA:
        case ATA_CMD_WRITE_DMA_EXT:
            this.current_interface.do_ata_write_sectors_dma();
            break;
        case ATA_CMD_PACKET:
            this.current_interface.do_atapi_dma();
            break;
        default:
            dbg_log(this.current_interface.name + ": spurious DMA command write, current command: " +
                    h(this.current_interface.current_command), LOG_DISK);
            dbg_log(this.current_interface.name + ": DMA clear status bit 1h, set status bit 2h", LOG_DISK);
            this.dma_status &= ~1;
            this.dma_status |= 2;
            this.push_irq();
            break;
    }
};

IDEChannel.prototype.push_irq = function()
{
    if((this.device_control_reg & ATA_CR_NIEN) === 0)
    {
        if(LOG_DETAILS & LOG_DETAIL_IRQ)
        {
            dbg_log(this.current_interface.name + ": push IRQ " + this.irq, LOG_DISK);
        }
        this.dma_status |= 4;
        this.cpu.device_raise_irq(this.irq);
    }
};

IDEChannel.prototype.get_state = function()
{
    var state = [];
    state[0] = this.master;
    state[1] = this.slave;
    state[2] = this.command_base;
    state[3] = this.irq;
    // state[4] = this.pci_id;
    state[5] = this.control_base;
    // state[6] = this.bus_master_base;
    state[7] = this.name;
    state[8] = this.device_control_reg;
    state[9] = this.prdt_addr;
    state[10] = this.dma_status;
    state[11] = this.current_interface === this.master;
    state[12] = this.dma_command;
    return state;
};

IDEChannel.prototype.set_state = function(state)
{
    this.master.set_state(state[0]);
    this.slave.set_state(state[1]);
    this.command_base = state[2];
    this.irq = state[3];
    // this.pci_id = state[4];
    this.control_base = state[5];
    // this.bus_master_base = state[6];
    this.name = state[7];
    this.device_control_reg = state[8];
    this.prdt_addr = state[9];
    this.dma_status = state[10];
    this.current_interface = state[11] ? this.master : this.slave;
    this.dma_command = state[12];
};

/**
 * @constructor
 * @param {IDEChannel} channel
 * @param {number} interface_nr
 * @param {boolean} is_cd
 */
function IDEInterface(channel, interface_nr, buffer, is_cd)
{
    this.channel = channel;
    this.name = channel.name + "." + interface_nr;

    /** @const @type {BusConnector} */
    this.bus = channel.bus;

    /** @const @type {number} */
    this.channel_nr = channel.channel_nr;

    /** @const @type {number} */
    this.interface_nr = interface_nr;

    /** @const @type {CPU} */
    this.cpu = channel.cpu;

    this.buffer = null;

    /** @type {boolean} */
    this.drive_connected = is_cd || !!buffer;

    /** @type {number} */
    this.sector_size = is_cd ? CDROM_SECTOR_SIZE : HD_SECTOR_SIZE;

    /** @type {boolean} */
    this.is_atapi = is_cd;

    /** @type {number} */
    this.sector_count = 0;

    /** @type {number} */
    this.head_count = this.is_atapi ? 1 : 0;

    /** @type {number} */
    this.sectors_per_track = 0;

    /** @type {number} */
    this.cylinder_count = 0;

    /** @type {number} */
    this.is_lba = 0;

    /** @type {number} */
    this.sector_count_reg = 0;

    /** @type {number} */
    this.lba_low_reg = 0;

    /** @type {number} */
    this.features_reg = 0;

    /** @type {number} */
    this.lba_mid_reg = 0;

    /** @type {number} */
    this.lba_high_reg = 0;

    /** @type {number} */
    this.head = 0;

    /** @type {number} */
    this.device_reg = 0;

    /** @type {number} */
    this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;

    /** @type {number} */
    this.sectors_per_drq = 0x80;

    /** @type {number} */
    this.error_reg = 0;

    /** @type {number} */
    this.data_pointer = 0;

    this.data = new Uint8Array(64 * 1024);
    this.data16 = new Uint16Array(this.data.buffer);
    this.data32 = new Int32Array(this.data.buffer);

    /** @type {number} */
    this.data_length = 0;

    /** @type {number} */
    this.data_end = 0;

    /** @type {number} */
    this.current_command = -1;

    /** @type {number} */
    this.write_dest = 0;

    // cancellation support
    this.last_io_id = 0;
    this.in_progress_io_ids = new Set();
    this.cancelled_io_ids = new Set();

    // ATAPI-only
    /** @type {number} */
    this.current_atapi_command = -1;

    /** @type {number} */
    this.atapi_sense_key = 0;

    /** @type {number} */
    this.atapi_add_sense = 0;

    /** @type {boolean} */
    this.medium_changed = false;

    this.set_disk_buffer(buffer);

    if(this.drive_connected)
    {
        dbg_log(`${this.name}: ${this.is_atapi ? "ATAPI CD-ROM" : "ATA HD"} device ready`, LOG_DISK);
    }

    Object.seal(this);
}

IDEInterface.prototype.has_disk = function()
{
    return !!this.buffer;
};

IDEInterface.prototype.eject = function()
{
    if(this.is_atapi && this.buffer)
    {
        this.medium_changed = true;
        this.buffer = null;
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ|ATA_SR_COND;
        this.error_reg = ATAPI_SK_UNIT_ATTENTION << 4;
        this.push_irq();
    }
};

IDEInterface.prototype.set_cdrom = function(buffer)
{
    if(this.is_atapi && buffer)
    {
        this.set_disk_buffer(buffer);
        this.medium_changed = true;
    }
};

IDEInterface.prototype.set_disk_buffer = function(buffer)
{
    if(!buffer)
    {
        return;
    }

    this.buffer = buffer;
    if(this.is_atapi)
    {
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ|ATA_SR_COND;
        this.error_reg = ATAPI_SK_UNIT_ATTENTION << 4;
    }
    this.sector_count = this.buffer.byteLength / this.sector_size;

    if(this.sector_count !== (this.sector_count | 0))
    {
        dbg_log(this.name + ": warning: disk size not aligned with sector size", LOG_DISK);
        this.sector_count = Math.ceil(this.sector_count);
    }

    if(this.is_atapi)
    {
        // default values: 1/2048
        this.head_count = 1;
        this.sectors_per_track = 2048;
    }
    else
    {
        // "default" values: 16/63
        // common: 255, 63
        this.head_count = 16;
        this.sectors_per_track = 63;
    }

    this.cylinder_count = this.sector_count / this.head_count / this.sectors_per_track;

    if(this.cylinder_count !== (this.cylinder_count | 0))
    {
        dbg_log(this.name + ": warning: rounding up cylinder count, choose different head number", LOG_DISK);
        this.cylinder_count = Math.floor(this.cylinder_count);
    }

    if(this.interface_nr === 0)
    {
        // for CMOS see:
        //   https://github.com/copy/v86/blob/master/src/rtc.js
        //   https://github.com/coreboot/seabios/blob/master/src/hw/rtc.h
        //   https://web.archive.org/web/20240119203005/http://www.bioscentral.com/misc/cmosmap.htm
        const rtc = this.cpu.devices.rtc;

        // master
        rtc.cmos_write(CMOS_BIOS_DISKTRANSFLAG,     // TODO: what is this doing, setting LBA translation?
                       rtc.cmos_read(CMOS_BIOS_DISKTRANSFLAG) | 1 << this.channel_nr * 4);

        // set hard disk type (CMOS_DISK_DATA = 0x12) of C: to 0b1111, keep type of D:
        //   bits 0-3: hard disk type of D:
        //   bits 4-7: hard disk type of C:
        // TODO: should this not also set CMOS_DISK_DRIVE1_TYPE to a hard disk type (see SeaBIOS rtc.h)?
        rtc.cmos_write(CMOS_DISK_DATA, rtc.cmos_read(CMOS_DISK_DATA) & 0x0F | 0xF0);

        const drive_reg = this.channel_nr === 0 ? CMOS_DISK_DRIVE1_CYL : CMOS_DISK_DRIVE2_CYL;  // 0x1B : 0x24 (drive C: or D:)
        rtc.cmos_write(drive_reg + 0, this.cylinder_count & 0xFF);        // number of cylinders least significant byte
        rtc.cmos_write(drive_reg + 1, this.cylinder_count >> 8 & 0xFF);   // number of cylinders most significant byte
        rtc.cmos_write(drive_reg + 2, this.head_count & 0xFF);            // number of heads
        rtc.cmos_write(drive_reg + 3, 0xFF);                              // write precomp cylinder least significant byte
        rtc.cmos_write(drive_reg + 4, 0xFF);                              // write precomp cylinder most significant byte
        rtc.cmos_write(drive_reg + 5, 0xC8);                              // control byte
        rtc.cmos_write(drive_reg + 6, this.cylinder_count & 0xFF);        // landing zone least significant byte
        rtc.cmos_write(drive_reg + 7, this.cylinder_count >> 8 & 0xFF);   // landing zone most significant byte
        rtc.cmos_write(drive_reg + 8, this.sectors_per_track & 0xFF);     // number of sectors
    }

    if(this.channel.cpu)
    {
        this.push_irq();
    }
};

IDEInterface.prototype.device_reset = function()
{
    if(this.is_atapi)
    {
        this.status_reg = 0;
        this.sector_count_reg = 1;
        this.error_reg = 1;
        this.lba_low_reg = 1;
        this.lba_mid_reg = ATAPI_SIGNATURE_LO;  // TODO: missing documentation
        this.lba_high_reg = ATAPI_SIGNATURE_HI;
    }
    else
    {
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_ERR;
        this.sector_count_reg = 1;
        this.error_reg = 1;
        this.lba_low_reg = 1;
        this.lba_mid_reg = 0;
        this.lba_high_reg = 0;
    }
    this.cancel_io_operations();
};

IDEInterface.prototype.push_irq = function()
{
    this.channel.push_irq();
};

IDEInterface.prototype.ata_abort_command = function()
{
    this.error_reg = ATA_ER_ABRT;
    this.status_reg = ATA_SR_DRDY|ATA_SR_ERR;
    this.push_irq();
};

IDEInterface.prototype.capture_regs = function()
{
    return `ST=${h(this.status_reg & 0xFF)} ER=${h(this.error_reg & 0xFF)} ` +
        `SC=${h(this.sector_count_reg & 0xFF)} LL=${h(this.lba_low_reg & 0xFF)} ` +
        `LM=${h(this.lba_mid_reg & 0xFF)} LH=${h(this.lba_high_reg & 0xFF)} ` +
        `FE=${h(this.features_reg & 0xFF)}`;
};

IDEInterface.prototype.ata_command = function(cmd)
{
    if(!this.drive_connected && cmd !== ATA_CMD_EXECUTE_DEVICE_DIAGNOSTIC)
    {
        dbg_log(`${this.name}: ATA command ${ATA_CMD_NAME[cmd]} (${h(cmd)}) ignored: no slave drive connected`, LOG_DISK);
        return;
    }

    const regs_pre = DEBUG ? this.capture_regs() : undefined;
    let do_dbg_log = DEBUG;

    this.current_command = cmd;
    this.error_reg = 0;

    switch(cmd)
    {
        case ATA_CMD_DEVICE_RESET:
            this.data_pointer = 0;
            this.data_end = 0;
            this.data_length = 0;
            this.device_reset();
            this.push_irq();
            break;

        case ATA_CMD_10h:
            this.lba_mid_reg = 0;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_READ_NATIVE_MAX_ADDRESS:
            var last_sector = this.sector_count - 1;
            this.lba_low_reg = last_sector & 0xFF;
            this.lba_mid_reg = last_sector >> 8 & 0xFF;
            this.lba_high_reg = last_sector >> 16 & 0xFF;
            this.device_reg = this.device_reg & 0xF0 | last_sector >> 24 & 0x0F;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_READ_NATIVE_MAX_ADDRESS_EXT:
            var last_sector = this.sector_count - 1;
            this.lba_low_reg = last_sector & 0xFF;
            this.lba_mid_reg = last_sector >> 8 & 0xFF;
            this.lba_high_reg = last_sector >> 16 & 0xFF;
            this.lba_low_reg |= last_sector >> 24 << 8 & 0xFF00;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_READ_SECTORS:
            do_dbg_log = false;
            if(this.is_atapi)
            {
                this.lba_mid_reg = ATAPI_SIGNATURE_LO;  // see [ATA8-ACS] 4.3
                this.lba_high_reg = ATAPI_SIGNATURE_HI;
                this.ata_abort_command();
            }
            else
            {
                this.ata_read_sectors(cmd);
            }
            break;

        case ATA_CMD_READ_SECTORS_EXT:
        case ATA_CMD_READ_MULTIPLE:
        case ATA_CMD_READ_MULTIPLE_EXT:
            do_dbg_log = false;
            if(this.is_atapi)
            {
                this.ata_abort_command();
            }
            else
            {
                this.ata_read_sectors(cmd);
            }
            break;

        case ATA_CMD_WRITE_SECTORS:
        case ATA_CMD_WRITE_SECTORS_EXT:
        case ATA_CMD_WRITE_MULTIPLE:
        case ATA_CMD_WRITE_MULTIPLE_EXT:
            do_dbg_log = false;
            if(this.is_atapi)
            {
                this.ata_abort_command();
            }
            else
            {
                this.ata_write_sectors(cmd);
            }
            break;

        case ATA_CMD_EXECUTE_DEVICE_DIAGNOSTIC:
            // the behaviour of this command is independent of the selected device
            this.channel.master.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.channel.master.error_reg = 0x01;    // Master drive passed, slave drive passed or not present
            this.channel.master.push_irq();
            if(this.channel.slave.drive_connected)
            {
                this.channel.slave.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
                this.channel.slave.error_reg = 0x01; // Slave drive passed
                this.channel.slave.push_irq();
            }
            break;

        case ATA_CMD_INITIALIZE_DEVICE_PARAMETERS:
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_PACKET:
            if(this.is_atapi)
            {
                do_dbg_log = false;
                this.data_allocate(12);
                this.data_end = 12;
                this.sector_count_reg = 0x01;   // 0x01: indicates transfer of a command packet (C/D)
                this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
                this.push_irq();
            }
            else
            {
                this.ata_abort_command();
            }
            break;

        case ATA_CMD_IDENTIFY_PACKET_DEVICE:
            if(this.is_atapi)
            {
                this.create_identify_packet();
                this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
                this.push_irq();
            }
            else
            {
                this.ata_abort_command();
            }
            break;

        case ATA_CMD_SET_MULTIPLE_MODE:
            // Logical sectors per DRQ Block in word 1
            dbg_log(this.name + ": logical sectors per DRQ Block: " + h(this.sector_count_reg & 0xFF), LOG_DISK);
            this.sectors_per_drq = this.sector_count_reg & 0xFF;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_READ_DMA:
        case ATA_CMD_READ_DMA_EXT:
            do_dbg_log = false;
            this.ata_read_sectors_dma(cmd);
            break;

        case ATA_CMD_WRITE_DMA:
        case ATA_CMD_WRITE_DMA_EXT:
            do_dbg_log = false;
            this.ata_write_sectors_dma(cmd);
            break;

        case ATA_CMD_READ_VERIFY_SECTORS:
            // TODO: check that lba_low/mid/high and sector_count regs are within the bounds of the disk's size
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_GET_MEDIA_STATUS:
            if(this.is_atapi)
            {
                if(!this.buffer)
                {
                    this.error_reg |= 0x02; // NM: No Media
                }
                if(this.medium_changed)
                {
                    this.error_reg |= 0x20; // MC: Media Change
                    this.medium_changed = false;
                }
                this.error_reg |= 0x40;     // WP: Write Protect
            }
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_STANDBY_IMMEDIATE:
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_IDLE_IMMEDIATE:
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_FLUSH_CACHE:
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_FLUSH_CACHE_EXT:
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_IDENTIFY_DEVICE:
            if(this.is_atapi)
            {
                this.lba_mid_reg = ATAPI_SIGNATURE_LO;  // see [ATA8-ACS] 4.3
                this.lba_high_reg = ATAPI_SIGNATURE_HI;
                this.ata_abort_command();
            }
            else
            {
                this.create_identify_packet();
                this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
                this.push_irq();
            }
            break;

        case ATA_CMD_SET_FEATURES:
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_MEDIA_LOCK:
            this.status_reg = ATA_SR_DRDY;
            this.push_irq();
            break;

        case ATA_CMD_SECURITY_FREEZE_LOCK:
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.push_irq();
            break;

        case ATA_CMD_SET_MAX:
            this.ata_abort_command();
            break;

        case ATA_CMD_NOP:
            this.ata_abort_command();
            break;

        case ATA_CMD_F0h:
            dbg_log(`${this.name}: error: unimplemented vendor-specific ATA command ${h(cmd)}: ABORT [${this.capture_regs()}]`, LOG_DISK);
            this.ata_abort_command();
            break;

        default:
            dbg_assert(false, `${this.name}: error: unimplemented ATA command ${h(cmd)}: ABORT [${this.capture_regs()}]`, LOG_DISK);
            this.ata_abort_command();
            break;
    }

    if(DEBUG && do_dbg_log)
    {
        const regs_msg = `[${regs_pre}] -> [${this.capture_regs()}]`;
        const result = this.status_reg & ATA_SR_ERR ? (this.error_reg & ATA_ER_ABRT ? "ABORT" : "ERROR") : "OK";
        dbg_log(`${this.name}: ATA command ${ATA_CMD_NAME[cmd]} (${h(cmd)}): ${result} ${regs_msg}`, LOG_DISK);
    }
};

IDEInterface.prototype.atapi_handle = function()
{
    const cmd = this.data[0];
    const cmd_name = ATAPI_CMD[cmd] ? ATAPI_CMD[cmd].name : "<undefined>";
    const cmd_flags = ATAPI_CMD[cmd] ? ATAPI_CMD[cmd].flags : ATAPI_CF_NONE;
    const regs_pre = DEBUG ? this.capture_regs() : undefined;

    let do_dbg_log = DEBUG;
    let dbg_log_extra;

    this.data_pointer = 0;
    this.current_atapi_command = cmd;

    if(cmd !== ATAPI_CMD_REQUEST_SENSE) // TODO
    {
        this.atapi_sense_key = 0;
        this.atapi_add_sense = 0;
    }

    if(!this.buffer && cmd_flags & ATAPI_CF_NEEDS_DISK)
    {
        this.atapi_check_condition_response(ATAPI_SK_NOT_READY, ATAPI_ASC_MEDIUM_NOT_PRESENT);
        this.push_irq();
        if(DEBUG)
        {
            dbg_log(`${this.name}: ATAPI command ${cmd_name} (${h(cmd)}) without medium: ERROR [${regs_pre}]`, LOG_DISK);
        }
        return;
    }

    switch(cmd)
    {
        case ATAPI_CMD_TEST_UNIT_READY:
            if(this.buffer)
            {
                this.data_allocate(0);
                this.data_end = this.data_length;
                this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            }
            else
            {
                this.atapi_check_condition_response(ATAPI_SK_NOT_READY, ATAPI_ASC_MEDIUM_NOT_PRESENT);
            }
            break;

        case ATAPI_CMD_REQUEST_SENSE:
            this.data_allocate(this.data[4]);
            this.data_end = this.data_length;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            this.data[0] = 0x80 | 0x70;             // valid | SCSI error code
            this.data[2] = this.atapi_sense_key;    // SCSI sense key
            this.data[7] = 8;                       // SCSI additional sense length (fixed 8 for this error code 0x70)
            this.data[12] = this.atapi_add_sense;   // SCSI additional sense code
            this.atapi_sense_key = 0;
            this.atapi_add_sense = 0;
            break;

        case ATAPI_CMD_INQUIRY:
            var length = this.data[4];
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            dbg_log_extra = "lun=" + h(this.data[1], 2) + " length=" + length;
            // for data layout see [CD-SCSI-2] "INQUIRY Command"
            this.data.set([
                // 0: Device-type, Removable, ANSI-Version, Response Format
                0x05, 0x80, 0x01, 0x31,
                // 4: Additional length, Reserved, Reserved, Reserved
                31, 0, 0, 0,
                // 8: Vendor Identification "SONY    "
                0x53, 0x4F, 0x4E, 0x59,
                0x20, 0x20, 0x20, 0x20,
                // 16: Product Identification "CD-ROM CDU-1000 "
                0x43, 0x44, 0x2D, 0x52,
                0x4F, 0x4D, 0x20, 0x43,
                0x44, 0x55, 0x2D, 0x31,
                0x30, 0x30, 0x30, 0x20,
                // 32: Product Revision Level "1.1a"
                0x31, 0x2E, 0x31, 0x61,
            ]);
            this.data_end = this.data_length = Math.min(36, length);
            break;

        case ATAPI_CMD_MODE_SENSE_6:
            this.data_allocate(this.data[4]);
            this.data_end = this.data_length;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            break;

        case ATAPI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
            this.data_allocate(0);
            this.data_end = this.data_length;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            break;

        case ATAPI_CMD_READ_CAPACITY:
            var count = this.sector_count - 1;
            this.data_set(new Uint8Array([
                count >> 24 & 0xFF,
                count >> 16 & 0xFF,
                count >> 8 & 0xFF,
                count & 0xFF,
                0,
                0,
                this.sector_size >> 8 & 0xFF,
                this.sector_size & 0xFF,
            ]));
            this.data_end = this.data_length;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            break;

        case ATAPI_CMD_READ_10:
        case ATAPI_CMD_READ_12:
            do_dbg_log = false;
            if(this.features_reg & 1)
            {
                this.atapi_read_dma(this.data);
            }
            else
            {
                this.atapi_read(this.data);
            }
            break;

        case ATAPI_CMD_READ_SUBCHANNEL:
            var length = this.data[8];
            dbg_log_extra = "length=" + length;
            this.data_allocate(Math.min(8, length));
            this.data_end = this.data_length;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            break;

        case ATAPI_CMD_READ_TOC_PMA_ATIP:
            var length = this.data[8] | this.data[7] << 8;
            var format = this.data[9] >> 6;
            dbg_log_extra = `${h(format, 2)} length=${length} ${!!(this.data[1] & 2)} ${h(this.data[6])}`;

            this.data_allocate(length);
            this.data_end = this.data_length;
            if(format === 0)
            {
                const sector_count = this.sector_count;
                this.data.set(new Uint8Array([
                    0, 18, // length
                    1, 1, // first and last session

                    0,
                    0x14,
                    1, // track number
                    0,
                    0, 0, 0, 0,

                    0,
                    0x16,
                    0xAA, // track number
                    0,
                    sector_count >> 24,
                    sector_count >> 16 & 0xFF,
                    sector_count >> 8 & 0xFF,
                    sector_count & 0xFF,
                ]));
            }
            else if(format === 1)
            {
                this.data.set(new Uint8Array([
                    0, 10, // length
                    1, 1, // first and last session
                    0, 0,
                    0, 0,
                    0, 0,
                    0, 0,
                ]));
            }
            else
            {
                dbg_assert(false, this.name + ": error: unimplemented format: " + format);
            }

            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            break;

        case ATAPI_CMD_GET_CONFIGURATION:
            var length = Math.min(this.data[8] | this.data[7] << 8, 32);
            dbg_log_extra = "length=" + length;
            this.data_allocate(length);
            this.data_end = this.data_length;
            this.data[0] = length - 4 >> 24 & 0xFF;
            this.data[1] = length - 4 >> 16 & 0xFF;
            this.data[2] = length - 4 >> 8 & 0xFF;
            this.data[3] = length - 4 & 0xFF;
            this.data[6] = 0x08;
            this.data[10] = 3;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            break;

        case ATAPI_CMD_READ_DISK_INFORMATION:
            this.data_allocate(0);
            this.data_end = this.data_length;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            break;

        case ATAPI_CMD_READ_TRACK_INFORMATION:
            dbg_log_extra = "unimplemented";
            this.atapi_check_condition_response(ATAPI_SK_ILLEGAL_REQUEST, ATAPI_ASC_INV_FIELD_IN_CMD_PACKET);
            break;

        case ATAPI_CMD_MODE_SENSE_10:
            var length = this.data[8] | this.data[7] << 8;
            var page_code = this.data[2];
            dbg_log_extra = "page_code=" + h(page_code) + " length=" + length;
            if(page_code === 0x2A)
            {
                this.data_allocate(Math.min(30, length));
            }
            this.data_end = this.data_length;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            break;

        case ATAPI_CMD_MECHANISM_STATUS:
            this.data_allocate(this.data[9] | this.data[8] << 8);
            this.data_end = this.data_length;
            this.data[5] = 1;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            break;

        case ATAPI_CMD_START_STOP_UNIT:
            var loej_start = this.data[4] & 0x3;
            dbg_log_extra = `Immed=${h(this.data[1] & 1)} LoEj/Start=${h(loej_start)}`;
            if(this.buffer && loej_start === 0x2)
            {
                dbg_log_extra += ": disk ejected";
                this.medium_changed = true;
                this.buffer = null;
            }
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.data_allocate(0);
            this.data_end = this.data_length;
            break;

        case ATAPI_CMD_PAUSE:
        case ATAPI_CMD_GET_EVENT_STATUS_NOTIFICATION:
            dbg_log_extra = "unimplemented";
            this.atapi_check_condition_response(ATAPI_SK_ILLEGAL_REQUEST, ATAPI_ASC_INV_FIELD_IN_CMD_PACKET);
            break;

        case ATAPI_CMD_READ_CD:
            dbg_log_extra = "unimplemented";
            this.data_allocate(0);
            this.data_end = this.data_length;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            break;

        default:
            dbg_assert(false, `${this.name}: error: unimplemented ATAPI command ${h(this.data[0])}`, LOG_DISK);
            this.atapi_check_condition_response(ATAPI_SK_ILLEGAL_REQUEST, ATAPI_ASC_INV_FIELD_IN_CMD_PACKET);
            break;
    }

    this.sector_count_reg = this.sector_count_reg & ~7 | 2;

    if((this.status_reg & ATA_SR_BSY) === 0)
    {
        this.push_irq();
    }

    if((this.status_reg & ATA_SR_BSY) === 0 && this.data_length === 0)
    {
        this.sector_count_reg |= 1;
        this.status_reg &= ~ATA_SR_DRQ;
    }

    if(DEBUG && do_dbg_log)
    {
        const regs_msg = `[${regs_pre}] -> [${this.capture_regs()}]`;
        const result = this.status_reg & ATA_SR_ERR ? (this.error_reg & ATA_ER_ABRT ? "ABORT" : "ERROR") : "OK";
        dbg_log_extra = dbg_log_extra ? ` ${dbg_log_extra}:` : "";
        dbg_log(`${this.name}: ATAPI command ${cmd_name} (${h(cmd)}):${dbg_log_extra} ${result} ${regs_msg}`, LOG_DISK);
    }
};

IDEInterface.prototype.atapi_check_condition_response = function(sense_key, additional_sense)
{
    // Setup ATA registers to CHECK CONDITION state.
    // The sense state (sense_key and additional_sense) must be requested
    // by the host using ATAPI_CMD_REQUEST_SENSE immediately following a
    // CHECK CONDITION response or else it will be lost.
    // https://github.com/qemu/qemu/blob/757a34115e7491744a63dfc3d291fd1de5297ee2/hw/ide/atapi.c#L186
    this.data_allocate(0);
    this.data_end = this.data_length;
    this.status_reg = ATA_SR_DRDY|ATA_SR_COND;
    this.error_reg = sense_key << 4;
    this.sector_count_reg = (this.sector_count_reg & ~7) | 2 | 1;
    this.atapi_sense_key = sense_key;
    this.atapi_add_sense = additional_sense;
};

IDEInterface.prototype.do_write = function()
{
    this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;

    dbg_assert(this.data_length <= this.data.length);
    var data = this.data.subarray(0, this.data_length);

    //dbg_log(hex_dump(data), LOG_DISK);
    dbg_assert(this.data_length % 512 === 0);
    this.ata_advance(this.current_command, this.data_length / 512);
    this.push_irq();

    this.buffer.set(this.write_dest, data, function()
    {
    });

    this.report_write(this.data_length);
};

IDEInterface.prototype.atapi_read = function(cmd)
{
    // Note: Big Endian
    var lba = cmd[2] << 24 | cmd[3] << 16 | cmd[4] << 8 | cmd[5];
    var count = cmd[0] === ATAPI_CMD_READ_12 ? (cmd[6] << 24 | cmd[7] << 16 | cmd[8] << 8 | cmd[9]) : (cmd[7] << 8 | cmd[8]);
    count >>>= 0;
    var flags = cmd[1];
    var byte_count = count * this.sector_size;
    var start = lba * this.sector_size;

    if(LOG_DETAILS & LOG_DETAIL_RW)
    {
        dbg_log(this.name + ": CD read lba=" + h(lba) +
                " lbacount=" + h(count) +
                " bytecount=" + h(byte_count) +
                " flags=" + h(flags), LOG_DISK);
    }

    this.data_length = 0;
    var req_length = this.lba_high_reg << 8 & 0xFF00 | this.lba_mid_reg & 0xFF;
    //dbg_log(this.name + ": " + h(this.lba_high_reg, 2) + " " + h(this.lba_mid_reg, 2), LOG_DISK);
    this.lba_mid_reg = this.lba_high_reg = 0; // oak technology driver (windows 3.0)

    if(req_length === 0xFFFF)
        req_length--;

    if(req_length > byte_count)
    {
        req_length = byte_count;
    }

    if(!this.buffer)
    {
        dbg_assert(false, this.name + ": CD read: no buffer", LOG_DISK);
        this.status_reg = 0xFF;
        this.error_reg = 0x41;
        this.push_irq();
    }
    else if(start >= this.buffer.byteLength)
    {
        dbg_assert(false, this.name + ": CD read: Outside of disk  end=" + h(start + byte_count) +
                          " size=" + h(this.buffer.byteLength), LOG_DISK);

        this.status_reg = 0xFF;
        this.push_irq();
    }
    else if(byte_count === 0)
    {
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;

        this.data_pointer = 0;
        //this.push_irq();
    }
    else
    {
        byte_count = Math.min(byte_count, this.buffer.byteLength - start);
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_BSY;
        this.report_read_start();

        this.read_buffer(start, byte_count, (data) =>
        {
            if(LOG_DETAILS & LOG_DETAIL_RW)
            {
                dbg_log(this.name + ": CD read: data arrived", LOG_DISK);
            }
            this.data_set(data);
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            this.sector_count_reg = this.sector_count_reg & ~7 | 2;

            this.push_irq();

            req_length &= ~3;

            this.data_end = req_length;
            if(this.data_end > this.data_length)
            {
                this.data_end = this.data_length;
            }
            this.lba_mid_reg = this.data_end & 0xFF;
            this.lba_high_reg = this.data_end >> 8 & 0xFF;

            this.report_read_end(byte_count);
        });
    }
};

IDEInterface.prototype.atapi_read_dma = function(cmd)
{
    // Note: Big Endian
    var lba = cmd[2] << 24 | cmd[3] << 16 | cmd[4] << 8 | cmd[5];
    var count = cmd[0] === ATAPI_CMD_READ_12 ? (cmd[6] << 24 | cmd[7] << 16 | cmd[8] << 8 | cmd[9]) : (cmd[7] << 8 | cmd[8]);
    count >>>= 0;
    var flags = cmd[1];
    var byte_count = count * this.sector_size;
    var start = lba * this.sector_size;

    dbg_log(this.name + ": CD read DMA lba=" + h(lba) +
            " lbacount=" + h(count) +
            " bytecount=" + h(byte_count) +
            " flags=" + h(flags), LOG_DISK);

    if(start >= this.buffer.byteLength)
    {
        dbg_assert(false, this.name + ": CD read: Outside of disk  end=" + h(start + byte_count) +
                          " size=" + h(this.buffer.byteLength), LOG_DISK);

        this.status_reg = 0xFF;
        this.push_irq();
    }
    else
    {
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_BSY;
        this.report_read_start();

        this.read_buffer(start, byte_count, (data) =>
        {
            dbg_log(this.name + ": atapi_read_dma: Data arrived", LOG_DISK);
            this.report_read_end(byte_count);
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            this.sector_count_reg = this.sector_count_reg & ~7 | 2;
            this.data_set(data);

            this.do_atapi_dma();
        });
    }
};

IDEInterface.prototype.do_atapi_dma = function()
{
    if((this.channel.dma_status & 1) === 0)
    {
        dbg_log(this.name + ": do_atapi_dma: Status not set", LOG_DISK);
        return;
    }

    if((this.status_reg & ATA_SR_DRQ) === 0)
    {
        dbg_log(this.name + ": do_atapi_dma: DRQ not set", LOG_DISK);
        return;
    }

    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.name + ": ATAPI DMA transfer len=" + this.data_length, LOG_DISK);
    }

    var prdt_start = this.channel.prdt_addr;
    var offset = 0;

    var data = this.data;

    do {
        var addr = this.cpu.read32s(prdt_start);
        var count = this.cpu.read16(prdt_start + 4);
        var end = this.cpu.read8(prdt_start + 7) & 0x80;

        if(!count)
        {
            count = 0x10000;
        }

        if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
        {
            dbg_log(this.name + ": DMA read dest=" + h(addr) + " count=" + h(count) + " datalen=" + h(this.data_length), LOG_DISK);
        }
        this.cpu.write_blob(data.subarray(offset, Math.min(offset + count, this.data_length)), addr);

        offset += count;
        prdt_start += 8;

        if(offset >= this.data_length && !end)
        {
            if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
            {
                dbg_log(this.name + ": leave early end=" + (+end) +
                        " offset=" + h(offset) +
                        " data_length=" + h(this.data_length) +
                        " cmd=" + h(this.current_command), LOG_DISK);
            }
            break;
        }
    }
    while(!end);

    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.name + ": end offset=" + offset, LOG_DISK);
    }

    this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
    this.channel.dma_status &= ~1;
    this.sector_count_reg = this.sector_count_reg & ~7 | 3;
    this.push_irq();
};

IDEInterface.prototype.read_data = function(length)
{
    if(this.data_pointer < this.data_end)
    {
        dbg_assert(this.data_pointer + length - 1 < this.data_end);
        dbg_assert(this.data_pointer % length === 0, h(this.data_pointer) + " " + length);

        if(length === 1)
        {
            var result = this.data[this.data_pointer];
        }
        else if(length === 2)
        {
            var result = this.data16[this.data_pointer >>> 1];
        }
        else
        {
            var result = this.data32[this.data_pointer >>> 2];
        }

        this.data_pointer += length;

        var align = (this.data_end & 0xFFF) === 0 ? 0xFFF : 0xFF;

        if(LOG_DETAILS & LOG_DETAIL_RW)
        {
            if((this.data_pointer & align) === 0)
            {
                dbg_log(this.name + ": read 1F0: " + h(this.data[this.data_pointer], 2) +
                            " cur=" + h(this.data_pointer) +
                            " cnt=" + h(this.data_length), LOG_DISK);
            }
        }

        if(this.data_pointer >= this.data_end)
        {
            this.read_end();
        }

        return result;
    }
    else
    {
        if(LOG_DETAILS & LOG_DETAIL_RW)
        {
            dbg_log(this.name + ": read 1F0: empty", LOG_DISK);
        }
        this.data_pointer += length;
        return 0;
    }
};

IDEInterface.prototype.read_end = function()
{
    if(LOG_DETAILS & LOG_DETAIL_RW)
    {
        dbg_log(this.name + ": read_end cmd=" + h(this.current_command) +
                " data_pointer=" + h(this.data_pointer) + " end=" + h(this.data_end) +
                " length=" + h(this.data_length), LOG_DISK);
    }

    if(this.current_command === ATA_CMD_PACKET)
    {
        if(this.data_end === this.data_length)
        {
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
            this.sector_count_reg = this.sector_count_reg & ~7 | 3;
            this.push_irq();
        }
        else
        {
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            this.sector_count_reg = this.sector_count_reg & ~7 | 2;
            this.push_irq();
            var byte_count = this.lba_high_reg << 8 & 0xFF00 | this.lba_mid_reg & 0xFF;

            if(this.data_end + byte_count > this.data_length)
            {
                this.lba_mid_reg = (this.data_length - this.data_end) & 0xFF;
                this.lba_high_reg = (this.data_length - this.data_end) >> 8 & 0xFF;
                this.data_end = this.data_length;
            }
            else
            {
                this.data_end += byte_count;
            }
            if(LOG_DETAILS & LOG_DETAIL_RW)
            {
                dbg_log(this.name + ": data_end=" + h(this.data_end), LOG_DISK);
            }
        }
    }
    else
    {
        this.error_reg = 0;
        if(this.data_pointer >= this.data_length)
        {
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
        }
        else
        {
            if(this.current_command === ATA_CMD_READ_MULTIPLE || this.current_command === ATA_CMD_READ_MULTIPLE_EXT)
            {
                var sector_count = Math.min(this.sectors_per_drq,
                    (this.data_length - this.data_end) / 512);
                dbg_assert(sector_count % 1 === 0);
            }
            else
            {
                dbg_assert(this.current_command === ATA_CMD_READ_SECTORS || this.current_command === ATA_CMD_READ_SECTORS_EXT);
                var sector_count = 1;
            }
            this.ata_advance(this.current_command, sector_count);
            this.data_end += 512 * sector_count;
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            this.push_irq();
        }
    }
};

IDEInterface.prototype.write_data_port = function(data, length)
{
    dbg_assert(this.data_pointer % length === 0);

    if(this.data_pointer >= this.data_end)
    {
        dbg_log(this.name + ": redundant write to data port: " + h(data) + " count=" +
                h(this.data_end) + " cur=" + h(this.data_pointer), LOG_DISK);
    }
    else
    {
        var align = (this.data_end & 0xFFF) === 0 ? 0xFFF : 0xFF;
        if(LOG_DETAILS & LOG_DETAIL_RW)
        {
            if((this.data_pointer + length & align) === 0 || this.data_end < 20)
            {
                dbg_log(this.name + ": data port: " + h(data >>> 0) + " count=" +
                        h(this.data_end) + " cur=" + h(this.data_pointer), LOG_DISK);
            }
        }

        if(length === 1)
        {
            this.data[this.data_pointer++] = data;
        }
        else if(length === 2)
        {
            this.data16[this.data_pointer >>> 1] = data;
            this.data_pointer += 2;
        }
        else
        {
            this.data32[this.data_pointer >>> 2] = data;
            this.data_pointer += 4;
        }

        dbg_assert(this.data_pointer <= this.data_end);
        if(this.data_pointer === this.data_end)
        {
            this.write_end();
        }
    }
};

IDEInterface.prototype.write_data_port8 = function(data)
{
    this.write_data_port(data, 1);
};

IDEInterface.prototype.write_data_port16 = function(data)
{
    this.write_data_port(data, 2);
};

IDEInterface.prototype.write_data_port32 = function(data)
{
    this.write_data_port(data, 4);
};

IDEInterface.prototype.write_end = function()
{
    if(this.current_command === ATA_CMD_PACKET)
    {
        this.atapi_handle();
    }
    else
    {
        if(LOG_DETAILS & LOG_DETAIL_RW)
        {
            dbg_log(this.name + ": write_end data_pointer=" + h(this.data_pointer) +
                " data_length=" + h(this.data_length), LOG_DISK);
        }

        if(this.data_pointer >= this.data_length)
        {
            this.do_write();
        }
        else
        {
            dbg_assert(this.current_command === ATA_CMD_WRITE_SECTORS ||
                this.current_command === ATA_CMD_WRITE_SECTORS_EXT ||
                this.current_command === ATA_CMD_WRITE_MULTIPLE_EXT,
                "Unexpected command: " + h(this.current_command));

            // XXX: Should advance here, but do_write does all the advancing
            //this.ata_advance(this.current_command, 1);
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            this.data_end += 512;
            this.push_irq();
        }
    }
};

IDEInterface.prototype.ata_advance = function(cmd, sectors)
{
    if(LOG_DETAILS & LOG_DETAIL_RW)
    {
        dbg_log(this.name + ": advance sectors=" + sectors + " old_sector_count_reg=" + this.sector_count_reg, LOG_DISK);
    }
    this.sector_count_reg -= sectors;

    if(cmd === ATA_CMD_READ_SECTORS_EXT ||
            cmd === ATA_CMD_READ_MULTIPLE ||
            cmd === ATA_CMD_READ_DMA_EXT ||
            cmd === ATA_CMD_WRITE_SECTORS_EXT ||
            cmd === ATA_CMD_WRITE_MULTIPLE ||
            cmd === ATA_CMD_WRITE_DMA_EXT)
    {
        var new_sector = sectors + this.get_lba48();
        this.lba_low_reg = new_sector & 0xFF | new_sector >> 16 & 0xFF00;
        this.lba_mid_reg = new_sector >> 8 & 0xFF;
        this.lba_high_reg = new_sector >> 16 & 0xFF;
    }
    else if(this.is_lba)
    {
        var new_sector = sectors + this.get_lba28();
        this.lba_low_reg = new_sector & 0xFF;
        this.lba_mid_reg = new_sector >> 8 & 0xFF;
        this.lba_high_reg = new_sector >> 16 & 0xFF;
        this.head = this.head & ~0xF | new_sector & 0xF;
    }
    else // chs
    {
        var new_sector = sectors + this.get_chs();

        var c = new_sector / (this.head_count * this.sectors_per_track) | 0;
        this.lba_mid_reg = c & 0xFF;
        this.lba_high_reg = c >> 8 & 0xFF;
        this.head = (new_sector / this.sectors_per_track | 0) % this.head_count & 0xF;
        this.lba_low_reg = (new_sector % this.sectors_per_track + 1) & 0xFF;

        dbg_assert(new_sector === this.get_chs());
    }
};

IDEInterface.prototype.ata_read_sectors = function(cmd)
{
    var is_lba48 = cmd === ATA_CMD_READ_SECTORS_EXT || cmd === ATA_CMD_READ_MULTIPLE;
    var count = this.get_count(is_lba48);
    var lba = this.get_lba(is_lba48);

    var is_single = cmd === ATA_CMD_READ_SECTORS || cmd === ATA_CMD_READ_SECTORS_EXT;

    var byte_count = count * this.sector_size;
    var start = lba * this.sector_size;

    if(LOG_DETAILS & LOG_DETAIL_RW)
    {
        dbg_log(this.name + ": ATA read cmd=" + h(cmd) +
                " mode=" + (this.is_lba ? "lba" : "chs") +
                " lba=" + h(lba) +
                " lbacount=" + h(count) +
                " bytecount=" + h(byte_count), LOG_DISK);
    }

    if(start + byte_count > this.buffer.byteLength)
    {
        dbg_assert(false, this.name + ": ATA read: Outside of disk", LOG_DISK);

        this.status_reg = 0xFF;
        this.push_irq();
    }
    else
    {
        this.status_reg = ATA_SR_DRDY|ATA_SR_BSY;
        this.report_read_start();

        this.read_buffer(start, byte_count, (data) =>
        {
            if(LOG_DETAILS & LOG_DETAIL_RW)
            {
                dbg_log(this.name + ": ata_read: Data arrived", LOG_DISK);
            }

            this.data_set(data);
            this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
            this.data_end = is_single ? 512 : Math.min(byte_count, this.sectors_per_drq * 512);
            this.ata_advance(cmd, is_single ? 1 : Math.min(count, this.sectors_per_track));

            this.push_irq();
            this.report_read_end(byte_count);
        });
    }
};

IDEInterface.prototype.ata_read_sectors_dma = function(cmd)
{
    var is_lba48 = cmd === ATA_CMD_READ_DMA_EXT;
    var count = this.get_count(is_lba48);
    var lba = this.get_lba(is_lba48);

    var byte_count = count * this.sector_size;
    var start = lba * this.sector_size;

    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.name + ": ATA DMA read lba=" + h(lba) +
                " lbacount=" + h(count) +
                " bytecount=" + h(byte_count), LOG_DISK);
    }

    if(start + byte_count > this.buffer.byteLength)
    {
        dbg_assert(false, this.name + ": ATA read: Outside of disk", LOG_DISK);

        this.status_reg = 0xFF;
        this.push_irq();
        return;
    }

    this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
    this.channel.dma_status |= 1;
};

IDEInterface.prototype.do_ata_read_sectors_dma = function()
{
    var cmd = this.current_command;

    var is_lba48 = cmd === ATA_CMD_READ_DMA_EXT;
    var count = this.get_count(is_lba48);
    var lba = this.get_lba(is_lba48);

    var byte_count = count * this.sector_size;
    var start = lba * this.sector_size;

    dbg_assert(lba < this.buffer.byteLength);

    this.report_read_start();

    var orig_prdt_start = this.channel.prdt_addr;

    this.read_buffer(start, byte_count, (data) =>
    {
        if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
        {
            dbg_log(this.name + ": do_ata_read_sectors_dma: Data arrived", LOG_DISK);
        }
        var prdt_start = this.channel.prdt_addr;
        var offset = 0;

        dbg_assert(orig_prdt_start === prdt_start);

        do {
            var prd_addr = this.cpu.read32s(prdt_start);
            var prd_count = this.cpu.read16(prdt_start + 4);
            var end = this.cpu.read8(prdt_start + 7) & 0x80;

            if(!prd_count)
            {
                prd_count = 0x10000;
                if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
                {
                    dbg_log(this.name + ": DMA: prd count was 0", LOG_DISK);
                }
            }

            if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
            {
                dbg_log(this.name + ": DMA read transfer dest=" + h(prd_addr) +
                    " prd_count=" + h(prd_count), LOG_DISK);
            }
            this.cpu.write_blob(data.subarray(offset, offset + prd_count), prd_addr);

            offset += prd_count;
            prdt_start += 8;
        }
        while(!end);

        dbg_assert(offset === byte_count);

        this.ata_advance(this.current_command, count);
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
        this.channel.dma_status &= ~1;
        this.current_command = -1;

        this.report_read_end(byte_count);

        this.push_irq();
    });
};

IDEInterface.prototype.ata_write_sectors = function(cmd)
{
    var is_lba48 = cmd === ATA_CMD_WRITE_SECTORS_EXT || cmd === ATA_CMD_WRITE_MULTIPLE;
    var count = this.get_count(is_lba48);
    var lba = this.get_lba(is_lba48);

    var is_single = cmd === ATA_CMD_WRITE_SECTORS || cmd === ATA_CMD_WRITE_SECTORS_EXT;

    var byte_count = count * this.sector_size;
    var start = lba * this.sector_size;

    if(LOG_DETAILS & LOG_DETAIL_RW)
    {
        dbg_log(this.name + ": ATA write lba=" + h(lba) +
                " mode=" + (this.is_lba ? "lba" : "chs") +
                " lbacount=" + h(count) +
                " bytecount=" + h(byte_count), LOG_DISK);
    }

    if(start + byte_count > this.buffer.byteLength)
    {
        dbg_assert(false, this.name + ": ATA write: Outside of disk", LOG_DISK);

        this.status_reg = 0xFF;
        this.push_irq();
    }
    else
    {
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
        this.data_allocate_noclear(byte_count);
        this.data_end = is_single ? 512 : Math.min(byte_count, this.sectors_per_drq * 512);
        this.write_dest = start;
    }
};

IDEInterface.prototype.ata_write_sectors_dma = function(cmd)
{
    var is_lba48 = cmd === ATA_CMD_WRITE_DMA_EXT;
    var count = this.get_count(is_lba48);
    var lba = this.get_lba(is_lba48);

    var byte_count = count * this.sector_size;
    var start = lba * this.sector_size;

    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.name + ": ATA DMA write lba=" + h(lba) +
                " lbacount=" + h(count) +
                " bytecount=" + h(byte_count), LOG_DISK);
    }

    if(start + byte_count > this.buffer.byteLength)
    {
        dbg_assert(false, this.name + ": ATA DMA write: Outside of disk", LOG_DISK);

        this.status_reg = 0xFF;
        this.push_irq();
        return;
    }

    this.status_reg = ATA_SR_DRDY|ATA_SR_DSC|ATA_SR_DRQ;
    this.channel.dma_status |= 1;
};

IDEInterface.prototype.do_ata_write_sectors_dma = function()
{
    var cmd = this.current_command;

    var is_lba48 = cmd === ATA_CMD_WRITE_DMA_EXT;
    var count = this.get_count(is_lba48);
    var lba = this.get_lba(is_lba48);

    var byte_count = count * this.sector_size;
    var start = lba * this.sector_size;

    var prdt_start = this.channel.prdt_addr;
    var offset = 0;

    if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
    {
        dbg_log(this.name + ": prdt addr: " + h(prdt_start, 8), LOG_DISK);
    }

    const buffer = new Uint8Array(byte_count);

    do {
        var prd_addr = this.cpu.read32s(prdt_start);
        var prd_count = this.cpu.read16(prdt_start + 4);
        var end = this.cpu.read8(prdt_start + 7) & 0x80;

        if(!prd_count)
        {
            prd_count = 0x10000;
            dbg_log(this.name + ": DMA: prd count was 0", LOG_DISK);
        }

        if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
        {
            dbg_log(this.name + ": DMA write transfer dest=" + h(prd_addr) + " prd_count=" + h(prd_count), LOG_DISK);
        }

        var slice = this.cpu.mem8.subarray(prd_addr, prd_addr + prd_count);
        dbg_assert(slice.length === prd_count);

        buffer.set(slice, offset);

        //if(DEBUG)
        //{
        //    dbg_log(hex_dump(slice), LOG_DISK);
        //}

        offset += prd_count;
        prdt_start += 8;
    }
    while(!end);

    dbg_assert(offset === buffer.length);

    this.buffer.set(start, buffer, () =>
    {
        if(LOG_DETAILS & LOG_DETAIL_RW_DMA)
        {
            dbg_log(this.name + ": DMA write completed", LOG_DISK);
        }
        this.ata_advance(this.current_command, count);
        this.status_reg = ATA_SR_DRDY|ATA_SR_DSC;
        this.push_irq();
        this.channel.dma_status &= ~1;
        this.current_command = -1;
    });

    this.report_write(byte_count);
};

IDEInterface.prototype.get_chs = function()
{
    var c = this.lba_mid_reg & 0xFF | this.lba_high_reg << 8 & 0xFF00;
    var h = this.head;
    var s = this.lba_low_reg & 0xFF;

    if(LOG_DETAILS & LOG_DETAIL_CHS)
    {
        dbg_log(this.name + ": get_chs: c=" + c + " h=" + h + " s=" + s, LOG_DISK);
    }

    return (c * this.head_count + h) * this.sectors_per_track + s - 1;
};

IDEInterface.prototype.get_lba28 = function()
{
    return this.lba_low_reg & 0xFF |
            this.lba_mid_reg << 8 & 0xFF00 |
            this.lba_high_reg << 16 & 0xFF0000 |
            (this.head & 0xF) << 24;
};

IDEInterface.prototype.get_lba48 = function()
{
    // Note: Bits over 32 missing
    return (this.lba_low_reg & 0xFF |
            this.lba_mid_reg << 8 & 0xFF00 |
            this.lba_high_reg << 16 & 0xFF0000 |
            (this.lba_low_reg >> 8) << 24 & 0xFF000000) >>> 0;
};

IDEInterface.prototype.get_lba = function(is_lba48)
{
    if(is_lba48)
    {
        return this.get_lba48();
    }
    else if(this.is_lba)
    {
        return this.get_lba28();
    }
    else
    {
        return this.get_chs();
    }
};

IDEInterface.prototype.get_count = function(is_lba48)
{
    if(is_lba48)
    {
        var count = this.sector_count_reg;
        if(count === 0) count = 0x10000;
        return count;
    }
    else
    {
        var count = this.sector_count_reg & 0xFF;
        if(count === 0) count = 0x100;
        return count;
    }
};

IDEInterface.prototype.create_identify_packet = function()
{
    const cylinder_count = Math.min(16383, this.cylinder_count);
    const strcpy_be16 = (out_buffer, ofs16, len16, str) => {
        let ofs8 = ofs16 << 1;
        const len8 = len16 << 1;
        const end8 = ofs8 + len8;
        out_buffer.fill(32, ofs8, len8); // fill output buffer with ASCII whitespace
        for(let i_str = 0; i_str < str.length && ofs8 < end8; i_str++) {
            if(i_str & 1) {
                out_buffer[ofs8] = str.charCodeAt(i_str);
                ofs8 += 2;
            }
            else {
                out_buffer[ofs8 + 1] = str.charCodeAt(i_str);
            }
        }
    };

    // Initialize array of 256 16-bit words (big-endian)
    // Best source for the lower 64 words of the memory layout used below:
    // - [ATA-retro]
    //   AT Attachment Interface for Disk Drives, Revision 4c
    //   https://dn790009.ca.archive.org/0/items/SCSISpecificationDocumentsATAATAPI/ATA_ATAPI/AT%20Attachment%20Interface%20for%20Disk%20Drives%20Revision%204c.pdf
    // For the words above 64 see [ATA-6] Table 27, [ATA8-ACS] 7.12 and 7.13.
    //
    // dead link: http://bochs.sourceforge.net/cgi-bin/lxr/source/iodev/harddrv.cc#L2821

    // most significant bit indicates ATAPI CD-ROM device
    const general_cfg = this.is_atapi ? 0x8540 : 0x0040;
    // multiword DMA transfer mode, meaning of 0x0407:
    // - 0x0007: Multiword DMA modes 2, 1 and 0 are supported
    // - 0x0400: Multiword DMA mode 2 is selected
    const multiword_dma_mode = this.current_command === ATA_CMD_PACKET ? 0 : 0x0407;
    // Major version number: bits 3/4/5/6 indicate support for ATA/ATAPI-3/4/5/6 (bits 0/1/2 are obsolete in [ATA-6])
    const major_version = 0x0000;   // device does not report version
    // supported ATA:   NOP, FLUSH CACHE, FLUSH CACHE EXT, 48-bit addr
    // supported ATAPI: NOP, DEVICE RESET, PACKET and FLUSH CACHE
    const feat_82 = this.is_atapi ? 1 << 14 | 1 << 9 | 1 << 5 : 1 << 14;
    const feat_83 = this.is_atapi ? 1 << 14 | 1 << 12 : 1 << 14 | 1 << 13 | 1 << 12 | 1 << 10;
    const feat_84 = this.is_atapi ? 1 << 14 : 1 << 14;

    this.data.fill(0, 0, 512);
    this.data_set([
        // 0: General configuration
        general_cfg & 0xFF, general_cfg >> 8 & 0xFF,
        // 1: Number of cylinders
        cylinder_count & 0xFF, cylinder_count >> 8 & 0xFF,
        // 2: reserved
        0, 0,
        // 3: Number of heads
        this.head_count & 0xFF, this.head_count >> 8 & 0xFF,
        // 4: Number of unformatted bytes per track
        this.sectors_per_track / 512 & 0xFF, this.sectors_per_track / 512 >> 8 & 0xFF,
        // 5: Number of unformatted bytes per sector
        0, 512 >> 8,
        // 6: Number of sectors per track
        this.sectors_per_track & 0xFF, this.sectors_per_track >> 8 & 0xFF,
        // 7-9: Vendor-unique
        0, 0, 0, 0,  0, 0,
        // 10-19: Serial number (20 ASCII characters, filled below)
        0, 0, 0, 0,  0, 0, 0, 0,
        0, 0, 0, 0,  0, 0, 0, 0,
        0, 0, 0, 0,
        // 20: Buffer type
        3, 0,
        // 21: Buffer size in 512 byte increments
        0, 2,
        // 22: Number of ECC bytes avail on read/write long cmds
        4, 0,
        // 23-26: Firmware revision (8 ASCII characters, filled below)
        0, 0, 0, 0,  0, 0, 0, 0,
        // 27-46: Model number (40 ASCII characters, filled below)
        0, 0, 0, 0,  0, 0, 0, 0,
        0, 0, 0, 0,  0, 0, 0, 0,
        0, 0, 0, 0,  0, 0, 0, 0,
        0, 0, 0, 0,  0, 0, 0, 0,
        0, 0, 0, 0,  0, 0, 0, 0,
        // 47: Max. number of sectors per interrupt on read/write multiple commands (1st byte) and Vendor-unique (2nd)
        0x80, 0,
        // 48: Indicates whether can perform doubleword I/O (1st byte) [0: no, 1: yes]
        1, 0,
        // 49: Vendor-unique (1st byte) and Capabilities (2nd) [2: Only LBA, 3: LBA and DMA]
        0, 2,
        // 50: reserved
        0, 0,
        // 51: PIO data transfer cycle timing mode
        0, 2,
        // 52: DMA data transfer cycle timing mode
        0, 2,
        // 53: Indicates whether fields 54-58 are valid (1st byte) [0: no, 1: yes]
        7, 0,
        // 54: Number of current cylinders
        cylinder_count & 0xFF, cylinder_count >> 8 & 0xFF,
        // 55: Number of current heads
        this.head_count & 0xFF, this.head_count >> 8 & 0xFF,
        // 56: Number of current sectors per track
        this.sectors_per_track, 0,
        // 57-58: Current capacity in sectors
        this.sector_count & 0xFF, this.sector_count >> 8 & 0xFF,
        this.sector_count >> 16 & 0xFF, this.sector_count >> 24 & 0xFF,
        // 59:  Multiple sector setting
        0, 0,
        // 60-61: Total number of user addressable sectors (LBA mode only)
        this.sector_count & 0xFF, this.sector_count >> 8 & 0xFF,
        this.sector_count >> 16 & 0xFF, this.sector_count >> 24 & 0xFF,
        // 62: Single word DMA transfer mode
        0, 0,
        // 63: Multiword DMA transfer mode (DMA supported mode, DMA selected mode)
        multiword_dma_mode & 0xFF, multiword_dma_mode >> 8 & 0xFF,

        // 64: PIO modes supported
        0, 0,
        // 65-68: fields related to cycle-time
        30, 0, 30, 0, 30, 0, 30, 0,
        // 69-74: reserved
        0, 0, 0, 0,  0, 0, 0, 0,
        0, 0, 0, 0,
        // 75: Queue depth
        0, 0,
        // 76-79: reserved
        0, 0, 0, 0,  0, 0, 0, 0,
        // 80: Major version number
        major_version & 0xFF, major_version >> 8 & 0xFF,
        // 81: Minor version number
        0, 0,
        // 82: Command set supported
        feat_82 & 0xFF, feat_82 >> 8 & 0xFF,
        // 83: Command set supported
        feat_83 & 0xFF, feat_83 >> 8 & 0xFF,
        // 84: Command set/feature supported extension
        feat_84 & 0xFF, feat_84 >> 8 & 0xFF,
        // 85: Command set/feature enabled (copy of 82)
        feat_82 & 0xFF, feat_82 >> 8 & 0xFF,
        // 86: Command set/feature enabled (copy of 83)
        feat_83 & 0xFF, feat_83 >> 8 & 0xFF,
        // 87: Command set/feature default (copy of 84)
        feat_84 & 0xFF, feat_84 >> 8 & 0xFF,
        // 88: DMA related field
        0, 0,
        // 89: Time required for security erase unit completion
        0, 0,
        // 90: Time required for Enhanced security erase completion
        0, 0,
        // 91: Current advanced power management value
        0, 0,
        // 92: Master Password Revision Code
        0, 0,
        // 93: Hardware reset result
        1, 0x60,
        // 94: Acoustic management value
        0, 0,
        // 95-99: reserved
        0, 0, 0, 0,  0, 0, 0, 0,
        0, 0,
        // 100-101: Maximum user LBA for 48-bit Address feature set.
        this.sector_count & 0xFF, this.sector_count >> 8 & 0xFF,
        this.sector_count >> 16 & 0xFF, this.sector_count >> 24 & 0xFF,
    ]);

    // 10-19 serial number
    strcpy_be16(this.data, 10, 10, `8086-86${this.channel_nr}${this.interface_nr}`);
    // 23-26 firmware revision
    strcpy_be16(this.data, 23, 4, "1.00");
    // 27-46 model number
    strcpy_be16(this.data, 27, 20, this.is_atapi ? "v86 ATAPI CD-ROM" : "v86 ATA HD");

    this.data_length = 512;
    this.data_end = 512;
};

IDEInterface.prototype.data_allocate = function(len)
{
    this.data_allocate_noclear(len);
    this.data32.fill(0, 0, len + 3 >> 2);
};

IDEInterface.prototype.data_allocate_noclear = function(len)
{
    if(this.data.length < len)
    {
        this.data = new Uint8Array(len + 3 & ~3);
        this.data16 = new Uint16Array(this.data.buffer);
        this.data32 = new Int32Array(this.data.buffer);
    }

    this.data_length = len;
    this.data_pointer = 0;
};

IDEInterface.prototype.data_set = function(data)
{
    this.data_allocate_noclear(data.length);
    this.data.set(data);
};

IDEInterface.prototype.report_read_start = function()
{
    this.bus.send("ide-read-start");
};

IDEInterface.prototype.report_read_end = function(byte_count)
{
    const sector_count = byte_count / this.sector_size | 0;
    this.bus.send("ide-read-end", [this.channel_nr, byte_count, sector_count]);
};

IDEInterface.prototype.report_write = function(byte_count)
{
    const sector_count = byte_count / this.sector_size | 0;
    this.bus.send("ide-write-end", [this.channel_nr, byte_count, sector_count]);
};

IDEInterface.prototype.read_buffer = function(start, length, callback)
{
    const id = this.last_io_id++;
    this.in_progress_io_ids.add(id);

    this.buffer.get(start, length, data =>
    {
        if(this.cancelled_io_ids.delete(id))
        {
            dbg_assert(!this.in_progress_io_ids.has(id));
            return;
        }

        const removed = this.in_progress_io_ids.delete(id);
        dbg_assert(removed);

        callback(data);
    });
};

IDEInterface.prototype.cancel_io_operations = function()
{
    for(const id of this.in_progress_io_ids)
    {
        this.cancelled_io_ids.add(id);
    }
    this.in_progress_io_ids.clear();
};

IDEInterface.prototype.get_state = function()
{
    var state = [];
    state[0] = this.sector_count_reg;
    state[1] = this.cylinder_count;
    state[2] = this.lba_high_reg;
    state[3] = this.lba_mid_reg;
    state[4] = this.data_pointer;
    state[5] = 0;
    state[6] = 0;
    state[7] = 0;
    state[8] = 0;
    state[9] = this.device_reg;
    state[10] = this.error_reg;
    state[11] = this.head;
    state[12] = this.head_count;
    state[13] = this.is_atapi;
    state[14] = this.is_lba;
    state[15] = this.features_reg;
    state[16] = this.data;
    state[17] = this.data_length;
    state[18] = this.lba_low_reg;
    state[19] = this.sector_count;
    state[20] = this.sector_size;
    state[21] = this.sectors_per_drq;
    state[22] = this.sectors_per_track;
    state[23] = this.status_reg;
    state[24] = this.write_dest;
    state[25] = this.current_command;
    state[26] = this.data_end;
    state[27] = this.current_atapi_command;
    state[28] = this.buffer;
    return state;
};

IDEInterface.prototype.set_state = function(state)
{
    this.sector_count_reg = state[0];
    this.cylinder_count = state[1];
    this.lba_high_reg = state[2];
    this.lba_mid_reg = state[3];
    this.data_pointer = state[4];

    this.device_reg = state[9];
    this.error_reg = state[10];
    this.head = state[11];
    this.head_count = state[12];
    this.is_atapi = state[13];
    this.is_lba = state[14];
    this.features_reg = state[15];
    this.data = state[16];
    this.data_length = state[17];
    this.lba_low_reg = state[18];
    this.sector_count = state[19];
    this.sector_size = state[20];
    this.sectors_per_drq = state[21];
    this.sectors_per_track = state[22];
    this.status_reg = state[23];
    this.write_dest = state[24];
    this.current_command = state[25];

    this.data_end = state[26];
    this.current_atapi_command = state[27];

    this.data16 = new Uint16Array(this.data.buffer);
    this.data32 = new Int32Array(this.data.buffer);

    this.buffer && this.buffer.set_state(state[28]);

    this.drive_connected = this.is_atapi || this.buffer;
    this.medium_changed = false;
};