#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>

#include <86box/86box.h>
#include <86box/device.h>
#include <86box/dma.h>
#include <86box/filters.h>
#include <86box/gameport.h>
#include <86box/io.h>
#include <86box/midi.h>
#include <86box/timer.h>
#include <86box/nvr.h>
#include <86box/pic.h>
#include <86box/sound.h>
#include <86box/snd_opl.h>
#include <86box/snd_ym7128.h>

typedef struct adgold_t {
    int adgold_irq_status;

    uint8_t adgold_eeprom[0x1a];

    uint8_t adgold_status;
    int     adgold_38x_state, adgold_38x_addr;
    uint8_t adgold_38x_regs[0x1a];

    int     adgold_mma_addr;
    uint8_t adgold_mma_regs[2][0xe];

    int     adgold_mma_enable[2];
    uint8_t adgold_mma_fifo[2][256];
    int     adgold_mma_fifo_start[2], adgold_mma_fifo_end[2];
    uint8_t adgold_mma_status;

    int16_t adgold_mma_out[2];
    int     adgold_mma_intpos[2];

    pc_timer_t adgold_mma_timer_count;

    uint8_t adgold_midi_ctrl, midi_queue[16];
    int     midi_r, midi_w;
    int     uart_in, uart_out, sysex;

    struct
    {
        int timer0_latch, timer0_count;
        int timerbase_latch, timerbase_count;
        int timer1_latch, timer1_count;
        int timer2_latch, timer2_count, timer2_read;

        int voice_count[2], voice_latch[2];
    } adgold_mma;

    opl_t    opl;
    ym7128_t ym7128;

    int fm_vol_l, fm_vol_r;
    int samp_vol_l, samp_vol_r;
    int aux_vol_l, aux_vol_r;
    int vol_l, vol_r;
    int treble, bass;

    int16_t opl_buffer[SOUNDBUFLEN * 2];
    int16_t mma_buffer[2][SOUNDBUFLEN];

    int pos;

    int gameport_enabled;

    int surround_enabled;
} adgold_t;

static int attenuation[0x40];
static int bass_attenuation[0x10] = {
    (int) (1.995 * 16384), /*12 dB - filter output is at +6 dB so we use 6 dB here*/
    (int) (1.995 * 16384),
    (int) (1.995 * 16384),
    (int) (1.413 * 16384), /*9 dB*/
    (int) (1 * 16384),     /*6 dB*/
    (int) (0.708 * 16384), /*3 dB*/
    (int) (0 * 16384),     /*0 dB*/
    (int) (0.708 * 16384), /*3 dB*/
    (int) (1 * 16384),     /*6 dB*/
    (int) (1.413 * 16384), /*9 dB*/
    (int) (1.995 * 16384), /*12 dB*/
    (int) (2.819 * 16384), /*15 dB*/
    (int) (2.819 * 16384),
    (int) (2.819 * 16384),
    (int) (2.819 * 16384),
    (int) (2.819 * 16384)
};

static int bass_cut[6] = {
    (int) (0.126 * 16384), /*-12 dB*/
    (int) (0.126 * 16384), /*-12 dB*/
    (int) (0.126 * 16384), /*-12 dB*/
    (int) (0.178 * 16384), /*-9 dB*/
    (int) (0.251 * 16384), /*-6 dB*/
    (int) (0.354 * 16384)  /*-3 dB - filter output is at +6 dB*/
};

static int treble_attenuation[0x10] = {
    (int) (1.995 * 16384), /*12 dB - filter output is at +6 dB so we use 6 dB here*/
    (int) (1.995 * 16384),
    (int) (1.995 * 16384),
    (int) (1.413 * 16384), /*9 dB*/
    (int) (1 * 16384),     /*6 dB*/
    (int) (0.708 * 16384), /*3 dB*/
    (int) (0 * 16384),     /*0 dB*/
    (int) (0.708 * 16384), /*3 dB*/
    (int) (1 * 16384),     /*6 dB*/
    (int) (1.413 * 16384), /*9 dB*/
    (int) (1.995 * 16384), /*12 dB*/
    (int) (1.995 * 16384),
    (int) (1.995 * 16384),
    (int) (1.995 * 16384),
    (int) (1.995 * 16384),
    (int) (1.995 * 16384)
};

static int treble_cut[6] = {
    (int) (0.126 * 16384), /*-12 dB*/
    (int) (0.126 * 16384), /*-12 dB*/
    (int) (0.126 * 16384), /*-12 dB*/
    (int) (0.178 * 16384), /*-9 dB*/
    (int) (0.251 * 16384), /*-6 dB*/
    (int) (0.354 * 16384)  /*-3 dB - filter output is at +6 dB*/
};

void adgold_timer_poll();
void adgold_update(adgold_t *adgold);

void
adgold_update_irq_status(adgold_t *adgold)
{
    uint8_t temp = 0xf;

    if (!(adgold->adgold_mma_regs[0][8] & 0x10) && (adgold->adgold_mma_status & 0x10)) /*Timer 0*/
        temp &= ~2;
    if (!(adgold->adgold_mma_regs[0][8] & 0x20) && (adgold->adgold_mma_status & 0x20)) /*Timer 1*/
        temp &= ~2;
    if (!(adgold->adgold_mma_regs[0][8] & 0x40) && (adgold->adgold_mma_status & 0x40)) /*Timer 2*/
        temp &= ~2;
    if (!(adgold->adgold_mma_regs[0][0xd] & 0x01) && (adgold->adgold_mma_status & 0x04))
        temp &= ~2;
    if (!(adgold->adgold_mma_regs[0][0xd] & 0x04) && (adgold->adgold_mma_status & 0x08))
        temp &= ~2;
    if (!(adgold->adgold_mma_regs[0][0xd] & 0x10) && (adgold->adgold_mma_status & 0x80))
        temp &= ~2;
    if ((adgold->adgold_mma_status & 0x01) && !(adgold->adgold_mma_regs[0][0xc] & 2))
        temp &= ~2;
    if ((adgold->adgold_mma_status & 0x02) && !(adgold->adgold_mma_regs[1][0xc] & 2))
        temp &= ~2;
    adgold->adgold_status = temp;

    if ((adgold->adgold_status ^ 0xf) && !adgold->adgold_irq_status) {
        picint(0x80);
    }

    adgold->adgold_irq_status = adgold->adgold_status ^ 0xf;
}

void
adgold_getsamp_dma(adgold_t *adgold, int channel)
{
    int temp;

    if ((adgold->adgold_mma_regs[channel][0xc] & 0x60) && (((adgold->adgold_mma_fifo_end[channel] - adgold->adgold_mma_fifo_start[channel]) & 255) >= 127))
        return;

    temp = dma_channel_read(1);
    if (temp == DMA_NODATA)
        return;
    adgold->adgold_mma_fifo[channel][adgold->adgold_mma_fifo_end[channel]] = temp;
    adgold->adgold_mma_fifo_end[channel]                                   = (adgold->adgold_mma_fifo_end[channel] + 1) & 255;
    if (adgold->adgold_mma_regs[channel][0xc] & 0x60) {
        temp                                                                   = dma_channel_read(1);
        adgold->adgold_mma_fifo[channel][adgold->adgold_mma_fifo_end[channel]] = temp;
        adgold->adgold_mma_fifo_end[channel]                                   = (adgold->adgold_mma_fifo_end[channel] + 1) & 255;
    }
    if (((adgold->adgold_mma_fifo_end[channel] - adgold->adgold_mma_fifo_start[channel]) & 255) >= adgold->adgold_mma_intpos[channel]) {
        adgold->adgold_mma_status &= ~(0x01 << channel);
        adgold_update_irq_status(adgold);
    }
}

void
adgold_write(uint16_t addr, uint8_t val, void *p)
{
    adgold_t *adgold = (adgold_t *) p;
    switch (addr & 7) {
        case 0:
        case 1:
            opl3_write(addr, val, &adgold->opl);
            break;

        case 2:
            if (val == 0xff) {
                adgold->adgold_38x_state = 1;
                return;
            }
            if (val == 0xfe) {
                adgold->adgold_38x_state = 0;
                return;
            }
            if (adgold->adgold_38x_state) /*Write to control chip*/
                adgold->adgold_38x_addr = val;
            else
                opl3_write(addr, val, &adgold->opl);
            break;
        case 3:
            if (adgold->adgold_38x_state) {
                if (adgold->adgold_38x_addr >= 0x19)
                    break;
                switch (adgold->adgold_38x_addr) {
                    case 0x00: /*Control/ID*/
                        if (val & 1)
                            memcpy(adgold->adgold_38x_regs, adgold->adgold_eeprom, 0x1a);
                        if (val & 2)
                            memcpy(adgold->adgold_eeprom, adgold->adgold_38x_regs, 0x1a);
                        break;

                    case 0x04: /*Final output volume left*/
                        adgold->adgold_38x_regs[0x04] = val;
                        adgold->vol_l                 = attenuation[val & 0x3f];
                        break;
                    case 0x05: /*Final output volume right*/
                        adgold->adgold_38x_regs[0x05] = val;
                        adgold->vol_r                 = attenuation[val & 0x3f];
                        break;
                    case 0x06: /*Bass*/
                        adgold->adgold_38x_regs[0x06] = val;
                        adgold->bass                  = val & 0xf;
                        break;
                    case 0x07: /*Treble*/
                        adgold->adgold_38x_regs[0x07] = val;
                        adgold->treble                = val & 0xf;
                        break;

                    case 0x09: /*FM volume left*/
                        adgold->adgold_38x_regs[0x09] = val;
                        adgold->fm_vol_l              = (int) (int8_t) (val - 128);
                        break;
                    case 0x0a: /*FM volume right*/
                        adgold->adgold_38x_regs[0x0a] = val;
                        adgold->fm_vol_r              = (int) (int8_t) (val - 128);
                        break;
                    case 0x0b: /*Sample volume left*/
                        adgold->adgold_38x_regs[0x0b] = val;
                        adgold->samp_vol_l            = (int) (int8_t) (val - 128);
                        break;
                    case 0x0c: /*Sample volume right*/
                        adgold->adgold_38x_regs[0x0c] = val;
                        adgold->samp_vol_r            = (int) (int8_t) (val - 128);
                        break;
                    case 0x0d: /*Aux volume left*/
                        adgold->adgold_38x_regs[0x0d] = val;
                        adgold->aux_vol_l             = (int) (int8_t) (val - 128);
                        break;
                    case 0x0e: /*Aux volume right*/
                        adgold->adgold_38x_regs[0x0e] = val;
                        adgold->aux_vol_r             = (int) (int8_t) (val - 128);
                        break;

                    case 0x18: /*Surround*/
                        adgold->adgold_38x_regs[0x18] = val;
                        ym7128_write(&adgold->ym7128, val);
                        break;

                    default:
                        adgold->adgold_38x_regs[adgold->adgold_38x_addr] = val;
                        break;
                }
            } else
                opl3_write(addr, val, &adgold->opl);
            break;
        case 4:
        case 6:
            adgold->adgold_mma_addr = val;
            break;
        case 5:
            if (adgold->adgold_mma_addr >= 0xf)
                break;
            switch (adgold->adgold_mma_addr) {
                case 0x2:
                    adgold->adgold_mma.timer0_latch = (adgold->adgold_mma.timer0_latch & 0xff00) | val;
                    break;
                case 0x3:
                    adgold->adgold_mma.timer0_latch = (adgold->adgold_mma.timer0_latch & 0xff) | (val << 8);
                    break;
                case 0x4:
                    adgold->adgold_mma.timerbase_latch = (adgold->adgold_mma.timerbase_latch & 0xf00) | val;
                    break;
                case 0x5:
                    adgold->adgold_mma.timerbase_latch = (adgold->adgold_mma.timerbase_latch & 0xff) | ((val & 0xf) << 8);
                    adgold->adgold_mma.timer1_latch    = val >> 4;
                    break;
                case 0x6:
                    adgold->adgold_mma.timer2_latch = (adgold->adgold_mma.timer2_latch & 0xff00) | val;
                    break;
                case 0x7:
                    adgold->adgold_mma.timer2_latch = (adgold->adgold_mma.timer2_latch & 0xff) | (val << 8);
                    break;

                case 0x8:
                    if ((val & 1) && !(adgold->adgold_mma_regs[0][8] & 1)) /*Reload timer 0*/
                        adgold->adgold_mma.timer0_count = adgold->adgold_mma.timer0_latch;

                    if ((val & 2) && !(adgold->adgold_mma_regs[0][8] & 2)) /*Reload timer 1*/
                        adgold->adgold_mma.timer1_count = adgold->adgold_mma.timer1_latch;

                    if ((val & 4) && !(adgold->adgold_mma_regs[0][8] & 4)) /*Reload timer 2*/
                        adgold->adgold_mma.timer2_count = adgold->adgold_mma.timer2_latch;

                    if ((val & 8) && !(adgold->adgold_mma_regs[0][8] & 8)) /*Reload base timer*/
                        adgold->adgold_mma.timerbase_count = adgold->adgold_mma.timerbase_latch;
                    break;

                case 0x9:
                    switch (val & 0x18) {
                        case 0x00:
                            adgold->adgold_mma.voice_latch[0] = 12;
                            break; /*44100 Hz*/
                        case 0x08:
                            adgold->adgold_mma.voice_latch[0] = 24;
                            break; /*22050 Hz*/
                        case 0x10:
                            adgold->adgold_mma.voice_latch[0] = 48;
                            break; /*11025 Hz*/
                        case 0x18:
                            adgold->adgold_mma.voice_latch[0] = 72;
                            break; /* 7350 Hz*/
                    }
                    if (val & 0x80) {
                        adgold->adgold_mma_enable[0]   = 0;
                        adgold->adgold_mma_fifo_end[0] = adgold->adgold_mma_fifo_start[0] = 0;
                        adgold->adgold_mma_status &= ~0x01;
                        adgold_update_irq_status(adgold);
                    }
                    if ((val & 0x01)) /*Start playback*/
                    {
                        if (!(adgold->adgold_mma_regs[0][0x9] & 1))
                            adgold->adgold_mma.voice_count[0] = adgold->adgold_mma.voice_latch[0];

                        if (adgold->adgold_mma_regs[0][0xc] & 1) {
                            if (adgold->adgold_mma_regs[0][0xc] & 0x80) {
                                adgold->adgold_mma_enable[1]      = 1;
                                adgold->adgold_mma.voice_count[1] = adgold->adgold_mma.voice_latch[1];

                                while (((adgold->adgold_mma_fifo_end[0] - adgold->adgold_mma_fifo_start[0]) & 255) < 128) {
                                    adgold_getsamp_dma(adgold, 0);
                                    adgold_getsamp_dma(adgold, 1);
                                }
                                if (((adgold->adgold_mma_fifo_end[0] - adgold->adgold_mma_fifo_start[0]) & 255) >= adgold->adgold_mma_intpos[0]) {
                                    adgold->adgold_mma_status &= ~0x01;
                                    adgold_update_irq_status(adgold);
                                }
                                if (((adgold->adgold_mma_fifo_end[1] - adgold->adgold_mma_fifo_start[1]) & 255) >= adgold->adgold_mma_intpos[1]) {
                                    adgold->adgold_mma_status &= ~0x02;
                                    adgold_update_irq_status(adgold);
                                }
                            } else {
                                while (((adgold->adgold_mma_fifo_end[0] - adgold->adgold_mma_fifo_start[0]) & 255) < 128) {
                                    adgold_getsamp_dma(adgold, 0);
                                }
                                if (((adgold->adgold_mma_fifo_end[0] - adgold->adgold_mma_fifo_start[0]) & 255) >= adgold->adgold_mma_intpos[0]) {
                                    adgold->adgold_mma_status &= ~0x01;
                                    adgold_update_irq_status(adgold);
                                }
                            }
                        }
                    }
                    adgold->adgold_mma_enable[0] = val & 0x01;
                    break;

                case 0xb:
                    if (((adgold->adgold_mma_fifo_end[0] - adgold->adgold_mma_fifo_start[0]) & 255) < 128) {
                        adgold->adgold_mma_fifo[0][adgold->adgold_mma_fifo_end[0]] = val;
                        adgold->adgold_mma_fifo_end[0]                             = (adgold->adgold_mma_fifo_end[0] + 1) & 255;
                        if (((adgold->adgold_mma_fifo_end[0] - adgold->adgold_mma_fifo_start[0]) & 255) >= adgold->adgold_mma_intpos[0]) {
                            adgold->adgold_mma_status &= ~0x01;
                            adgold_update_irq_status(adgold);
                        }
                    }
                    break;

                case 0xc:
                    adgold->adgold_mma_intpos[0] = (7 - ((val >> 2) & 7)) * 8;
                    break;

                case 0xd:
                    adgold->adgold_midi_ctrl = val & 0x3f;

                    if ((adgold->adgold_midi_ctrl & 0x0f) != 0x0f) {
                        if ((adgold->adgold_midi_ctrl & 0x0f) == 0x00) {
                            adgold->uart_out = 0;
                            adgold->uart_in  = 0;
                            adgold->midi_w   = 0;
                            adgold->midi_r   = 0;
                            adgold->adgold_mma_status &= ~0x8c;
                        } else {
                            if (adgold->adgold_midi_ctrl & 0x01)
                                adgold->uart_in = 1;
                            if (adgold->adgold_midi_ctrl & 0x04)
                                adgold->uart_out = 1;
                            if (adgold->adgold_midi_ctrl & 0x02) {
                                adgold->uart_in = 0;
                                adgold->midi_w  = 0;
                                adgold->midi_r  = 0;
                            }
                            if (adgold->adgold_midi_ctrl & 0x08)
                                adgold->uart_out = 0;
                            adgold->adgold_mma_status &= ~0x80;
                        }
                    } else
                        adgold->adgold_mma_status &= ~0x8c;

                    adgold_update_irq_status(adgold);
                    break;

                case 0xe:
                    if (adgold->uart_out) {
                        midi_raw_out_byte(val);

                        adgold->adgold_mma_status &= ~0x08;
                        adgold_update_irq_status(adgold);
                    }
                    break;
            }
            adgold->adgold_mma_regs[0][adgold->adgold_mma_addr] = val;
            break;
        case 7:
            if (adgold->adgold_mma_addr >= 0xe)
                break;
            switch (adgold->adgold_mma_addr) {
                case 0x9:
                    adgold_update(adgold);
                    switch (val & 0x18) {
                        case 0x00:
                            adgold->adgold_mma.voice_latch[1] = 12;
                            break; /*44100 Hz*/
                        case 0x08:
                            adgold->adgold_mma.voice_latch[1] = 24;
                            break; /*22050 Hz*/
                        case 0x10:
                            adgold->adgold_mma.voice_latch[1] = 48;
                            break; /*11025 Hz*/
                        case 0x18:
                            adgold->adgold_mma.voice_latch[1] = 72;
                            break; /* 7350 Hz*/
                    }
                    if (val & 0x80) {
                        adgold->adgold_mma_enable[1]   = 0;
                        adgold->adgold_mma_fifo_end[1] = adgold->adgold_mma_fifo_start[1] = 0;
                        adgold->adgold_mma_status &= ~0x02;
                        adgold_update_irq_status(adgold);
                    }
                    if ((val & 0x01)) /*Start playback*/
                    {
                        if (!(adgold->adgold_mma_regs[1][0x9] & 1))
                            adgold->adgold_mma.voice_count[1] = adgold->adgold_mma.voice_latch[1];

                        if (adgold->adgold_mma_regs[1][0xc] & 1) {
                            while (((adgold->adgold_mma_fifo_end[1] - adgold->adgold_mma_fifo_start[1]) & 255) < 128) {
                                adgold_getsamp_dma(adgold, 1);
                            }
                        }
                    }
                    adgold->adgold_mma_enable[1] = val & 0x01;
                    break;

                case 0xb:
                    if (((adgold->adgold_mma_fifo_end[1] - adgold->adgold_mma_fifo_start[1]) & 255) < 128) {
                        adgold->adgold_mma_fifo[1][adgold->adgold_mma_fifo_end[1]] = val;
                        adgold->adgold_mma_fifo_end[1]                             = (adgold->adgold_mma_fifo_end[1] + 1) & 255;
                        if (((adgold->adgold_mma_fifo_end[1] - adgold->adgold_mma_fifo_start[1]) & 255) >= adgold->adgold_mma_intpos[1]) {
                            adgold->adgold_mma_status &= ~0x02;
                            adgold_update_irq_status(adgold);
                        }
                    }
                    break;

                case 0xc:
                    adgold->adgold_mma_intpos[1] = (7 - ((val >> 2) & 7)) * 8;
                    break;
            }
            adgold->adgold_mma_regs[1][adgold->adgold_mma_addr] = val;
            break;
    }
}

uint8_t
adgold_read(uint16_t addr, void *p)
{
    adgold_t *adgold = (adgold_t *) p;
    uint8_t   temp   = 0;

    switch (addr & 7) {
        case 0:
        case 1:
            temp = opl3_read(addr, &adgold->opl);
            break;

        case 2:
            if (adgold->adgold_38x_state) /*Read from control chip*/
                temp = adgold->adgold_status;
            else
                temp = opl3_read(addr, &adgold->opl);
            break;

        case 3:
            if (adgold->adgold_38x_state) {
                if (adgold->adgold_38x_addr >= 0x19)
                    temp = 0xff;
                switch (adgold->adgold_38x_addr) {
                    case 0x00: /*Control/ID*/
                        if (adgold->surround_enabled)
                            temp = 0x51; /*8-bit ISA, surround module, no telephone/CD-ROM*/
                        else
                            temp = 0x71; /*8-bit ISA, no telephone/surround/CD-ROM*/
                        break;

                    default:
                        temp = adgold->adgold_38x_regs[adgold->adgold_38x_addr];
                }
            } else
                temp = opl3_read(addr, &adgold->opl);
            break;

        case 4:
        case 6:
            temp = adgold->adgold_mma_status;
            adgold->adgold_mma_status &= ~0xf3; /*JUKEGOLD expects timer status flags to auto-clear*/
            adgold_update_irq_status(adgold);
            break;
        case 5:
            if (adgold->adgold_mma_addr >= 0xf)
                temp = 0xff;
            switch (adgold->adgold_mma_addr) {
                case 6: /*Timer 2 low*/
                    adgold->adgold_mma.timer2_read = adgold->adgold_mma.timer2_count;
                    adgold->adgold_mma_status |= 0x40;
                    temp = adgold->adgold_mma.timer2_read & 0xff;
                    break;
                case 7: /*Timer 2 high*/
                    temp = adgold->adgold_mma.timer2_read >> 8;
                    break;

                case 0xe:
                    temp = 0;
                    if (adgold->uart_in) {
                        temp = adgold->midi_queue[adgold->midi_r];
                        if (adgold->midi_r != adgold->midi_w) {
                            adgold->midi_r++;
                            adgold->midi_r &= 0x0f;
                        }
                        adgold->adgold_mma_status &= ~0x04;
                        adgold_update_irq_status(adgold);
                    }
                    break;

                default:
                    temp = adgold->adgold_mma_regs[0][adgold->adgold_mma_addr];
                    break;
            }
            break;
        case 7:
            if (adgold->adgold_mma_addr >= 0xf)
                temp = 0xff;
            else
                temp = adgold->adgold_mma_regs[1][adgold->adgold_mma_addr];
            break;
    }
    return temp;
}

void
adgold_update(adgold_t *adgold)
{
    for (; adgold->pos < sound_pos_global; adgold->pos++) {
        adgold->mma_buffer[0][adgold->pos] = adgold->mma_buffer[1][adgold->pos] = 0;

        if (adgold->adgold_mma_regs[0][9] & 0x20)
            adgold->mma_buffer[0][adgold->pos] += adgold->adgold_mma_out[0] / 2;
        if (adgold->adgold_mma_regs[0][9] & 0x40)
            adgold->mma_buffer[1][adgold->pos] += adgold->adgold_mma_out[0] / 2;

        if (adgold->adgold_mma_regs[1][9] & 0x20)
            adgold->mma_buffer[0][adgold->pos] += adgold->adgold_mma_out[1] / 2;
        if (adgold->adgold_mma_regs[1][9] & 0x40)
            adgold->mma_buffer[1][adgold->pos] += adgold->adgold_mma_out[1] / 2;
    }
}

void
adgold_mma_poll(adgold_t *adgold, int channel)
{
    int16_t dat;

    adgold_update(adgold);

    if (adgold->adgold_mma_fifo_start[channel] != adgold->adgold_mma_fifo_end[channel]) {
        switch (adgold->adgold_mma_regs[channel][0xc] & 0x60) {
            case 0x00: /*8-bit*/
                dat                                    = adgold->adgold_mma_fifo[channel][adgold->adgold_mma_fifo_start[channel]] * 256;
                adgold->adgold_mma_out[channel]        = dat;
                adgold->adgold_mma_fifo_start[channel] = (adgold->adgold_mma_fifo_start[channel] + 1) & 255;
                break;

            case 0x40: /*12-bit sensible format*/
                if (((adgold->adgold_mma_fifo_end[channel] - adgold->adgold_mma_fifo_start[channel]) & 255) < 2)
                    return;

                dat                                    = adgold->adgold_mma_fifo[channel][adgold->adgold_mma_fifo_start[channel]] & 0xf0;
                adgold->adgold_mma_fifo_start[channel] = (adgold->adgold_mma_fifo_start[channel] + 1) & 255;
                dat |= (adgold->adgold_mma_fifo[channel][adgold->adgold_mma_fifo_start[channel]] << 8);
                adgold->adgold_mma_fifo_start[channel] = (adgold->adgold_mma_fifo_start[channel] + 1) & 255;
                adgold->adgold_mma_out[channel]        = dat;
                break;
        }

        if (adgold->adgold_mma_regs[channel][0xc] & 1) {
            adgold_getsamp_dma(adgold, channel);
        }
        if (((adgold->adgold_mma_fifo_end[channel] - adgold->adgold_mma_fifo_start[channel]) & 255) < adgold->adgold_mma_intpos[channel] && !(adgold->adgold_mma_status & 0x01)) {
            adgold->adgold_mma_status |= 1 << channel;
            adgold_update_irq_status(adgold);
        }
    }
    if (adgold->adgold_mma_fifo_start[channel] == adgold->adgold_mma_fifo_end[channel]) {
        adgold->adgold_mma_enable[channel] = 0;
    }
}

void
adgold_timer_poll(void *p)
{
    adgold_t *adgold = (adgold_t *) p;

    timer_advance_u64(&adgold->adgold_mma_timer_count, (uint64_t) ((double) TIMER_USEC * 1.88964));

    if (adgold->adgold_midi_ctrl & 0x3f) {
        if ((adgold->adgold_midi_ctrl & 0x3f) != 0x3f) {
            if (adgold->uart_out)
                adgold->adgold_mma_status |= 0x08;
            if (adgold->adgold_midi_ctrl & 0x10)
                adgold->adgold_mma_status |= 0x80;
        }
        adgold_update_irq_status(adgold);
    }

    if (adgold->adgold_mma_regs[0][8] & 0x01) /*Timer 0*/
    {
        adgold->adgold_mma.timer0_count--;
        if (!adgold->adgold_mma.timer0_count) {
            adgold->adgold_mma.timer0_count = adgold->adgold_mma.timer0_latch;
            adgold->adgold_mma_status |= 0x10;
            adgold_update_irq_status(adgold);
        }
    }
    if (adgold->adgold_mma_regs[0][8] & 0x08) /*Base timer*/
    {
        adgold->adgold_mma.timerbase_count--;
        if (!adgold->adgold_mma.timerbase_count) {
            adgold->adgold_mma.timerbase_count = adgold->adgold_mma.timerbase_latch;
            if (adgold->adgold_mma_regs[0][8] & 0x02) /*Timer 1*/
            {
                adgold->adgold_mma.timer1_count--;
                if (!adgold->adgold_mma.timer1_count) {
                    adgold->adgold_mma.timer1_count = adgold->adgold_mma.timer1_latch;
                    adgold->adgold_mma_status |= 0x20;
                    adgold_update_irq_status(adgold);
                }
            }
            if (adgold->adgold_mma_regs[0][8] & 0x04) /*Timer 2*/
            {
                adgold->adgold_mma.timer2_count--;
                if (!adgold->adgold_mma.timer2_count) {
                    adgold->adgold_mma.timer2_count = adgold->adgold_mma.timer2_latch;
                    adgold->adgold_mma_status |= 0x40;
                    adgold_update_irq_status(adgold);
                }
            }
        }
    }

    if (adgold->adgold_mma_enable[0]) {
        adgold->adgold_mma.voice_count[0]--;
        if (!adgold->adgold_mma.voice_count[0]) {
            adgold->adgold_mma.voice_count[0] = adgold->adgold_mma.voice_latch[0];
            adgold_mma_poll(adgold, 0);
        }
    }
    if (adgold->adgold_mma_enable[1]) {
        adgold->adgold_mma.voice_count[1]--;
        if (!adgold->adgold_mma.voice_count[1]) {
            adgold->adgold_mma.voice_count[1] = adgold->adgold_mma.voice_latch[1];
            adgold_mma_poll(adgold, 1);
        }
    }
}

static void
adgold_get_buffer(int32_t *buffer, int len, void *p)
{
    adgold_t *adgold        = (adgold_t *) p;
    int16_t  *adgold_buffer = malloc(sizeof(int16_t) * len * 2);
    if (adgold_buffer == NULL)
        fatal("adgold_buffer = NULL");

    int c;

    opl3_update(&adgold->opl);
    adgold_update(adgold);

    for (c = 0; c < len * 2; c += 2) {
        adgold_buffer[c] = ((adgold->opl.buffer[c] * adgold->fm_vol_l) >> 7) / 2;
        adgold_buffer[c] += ((adgold->mma_buffer[0][c >> 1] * adgold->samp_vol_l) >> 7) / 4;
        adgold_buffer[c + 1] = ((adgold->opl.buffer[c + 1] * adgold->fm_vol_r) >> 7) / 2;
        adgold_buffer[c + 1] += ((adgold->mma_buffer[1][c >> 1] * adgold->samp_vol_r) >> 7) / 4;
    }

    if (adgold->surround_enabled)
        ym7128_apply(&adgold->ym7128, adgold_buffer, len);

    switch (adgold->adgold_38x_regs[0x8] & 6) {
        case 0:
            for (c = 0; c < len * 2; c++)
                adgold_buffer[c] = 0;
            break;
        case 2: /*Left channel only*/
            for (c = 0; c < len * 2; c += 2)
                adgold_buffer[c + 1] = adgold_buffer[c];
            break;
        case 4: /*Right channel only*/
            for (c = 0; c < len * 2; c += 2)
                adgold_buffer[c] = adgold_buffer[c + 1];
            break;
        case 6: /*Left and right channels*/
            break;
    }

    switch (adgold->adgold_38x_regs[0x8] & 0x18) {
        case 0x00: /*Forced mono*/
            for (c = 0; c < len * 2; c += 2)
                adgold_buffer[c] = adgold_buffer[c + 1] = ((int32_t) adgold_buffer[c] + (int32_t) adgold_buffer[c + 1]) / 2;
            break;
        case 0x08: /*Linear stereo*/
            break;
        case 0x10: /*Pseudo stereo*/
            /*Filter left channel, leave right channel unchanged*/
            /*Filter cutoff is largely a guess*/
            for (c = 0; c < len * 2; c += 2)
                adgold_buffer[c] += adgold_pseudo_stereo_iir(adgold_buffer[c]);
            break;
        case 0x18: /*Spatial stereo*/
            /*Quite probably wrong, I only have the diagram in the TDA8425 datasheet
              and a very vague understanding of how op-amps work to go on*/
            for (c = 0; c < len * 2; c += 2) {
                int16_t l = adgold_buffer[c];
                int16_t r = adgold_buffer[c + 1];

                adgold_buffer[c] += (r / 3) + ((l * 2) / 3);
                adgold_buffer[c + 1] += (l / 3) + ((r * 2) / 3);
            }
            break;
    }

    for (c = 0; c < len * 2; c += 2) {
        int32_t temp, lowpass, highpass;

        /*Output is deliberately halved to avoid clipping*/
        temp     = ((int32_t) adgold_buffer[c] * adgold->vol_l) >> 17;
        lowpass  = adgold_lowpass_iir(0, temp);
        highpass = adgold_highpass_iir(0, temp);
        if (adgold->bass > 6)
            temp += (lowpass * bass_attenuation[adgold->bass]) >> 14;
        else if (adgold->bass < 6)
            temp = highpass + ((temp * bass_cut[adgold->bass]) >> 14);
        if (adgold->treble > 6)
            temp += (highpass * treble_attenuation[adgold->treble]) >> 14;
        else if (adgold->treble < 6)
            temp = lowpass + ((temp * treble_cut[adgold->treble]) >> 14);
        if (temp < -32768)
            temp = -32768;
        if (temp > 32767)
            temp = 32767;
        buffer[c] += temp;

        temp     = ((int32_t) adgold_buffer[c + 1] * adgold->vol_r) >> 17;
        lowpass  = adgold_lowpass_iir(1, temp);
        highpass = adgold_highpass_iir(1, temp);
        if (adgold->bass > 6)
            temp += (lowpass * bass_attenuation[adgold->bass]) >> 14;
        else if (adgold->bass < 6)
            temp = highpass + ((temp * bass_cut[adgold->bass]) >> 14);
        if (adgold->treble > 6)
            temp += (highpass * treble_attenuation[adgold->treble]) >> 14;
        else if (adgold->treble < 6)
            temp = lowpass + ((temp * treble_cut[adgold->treble]) >> 14);
        if (temp < -32768)
            temp = -32768;
        if (temp > 32767)
            temp = 32767;
        buffer[c + 1] += temp;
    }

    adgold->opl.pos = 0;
    adgold->pos     = 0;

    free(adgold_buffer);
}

static void
adgold_filter_cd_audio(int channel, double *buffer, void *p)
{
    adgold_t *adgold = (adgold_t *) p;
    double    c;
    int       aux = channel ? adgold->aux_vol_r : adgold->aux_vol_l;
    int       vol = channel ? adgold->vol_r : adgold->vol_l;

    c       = ((((*buffer) * aux) / 4096.0) * vol) / 4096.0;
    *buffer = c;
}

static void
adgold_input_msg(void *p, uint8_t *msg, uint32_t len)
{
    adgold_t *adgold = (adgold_t *) p;
    uint8_t   i;

    if (adgold->sysex)
        return;

    if (adgold->uart_in) {
        adgold->adgold_mma_status |= 0x04;

        for (i = 0; i < len; i++) {
            adgold->midi_queue[adgold->midi_w++] = msg[i];
            adgold->midi_w &= 0x0f;
        }

        adgold_update_irq_status(adgold);
    }
}

static int
adgold_input_sysex(void *p, uint8_t *buffer, uint32_t len, int abort)
{
    adgold_t *adgold = (adgold_t *) p;
    uint32_t  i;

    if (abort) {
        adgold->sysex = 0;
        return 0;
    }
    adgold->sysex = 1;
    for (i = 0; i < len; i++) {
        if (adgold->midi_r == adgold->midi_w)
            return (len - i);
        adgold->midi_queue[adgold->midi_w++] = buffer[i];
        adgold->midi_w &= 0x0f;
    }
    adgold->sysex = 0;
    return 0;
}

void *
adgold_init(const device_t *info)
{
    FILE     *f;
    int       c;
    double    out;
    adgold_t *adgold = malloc(sizeof(adgold_t));
    memset(adgold, 0, sizeof(adgold_t));

    adgold->surround_enabled = device_get_config_int("surround");

    adgold->gameport_enabled = device_get_config_int("gameport");

    opl3_init(&adgold->opl);
    if (adgold->surround_enabled)
        ym7128_init(&adgold->ym7128);

    out = 65536.0; /*Main volume control ranges from +6 dB to -64 dB in 2 dB steps, then remaining settings are -80 dB (effectively 0)*/
    for (c = 0x3f; c >= 0x1c; c--) {
        attenuation[c] = (int) out;
        out /= 1.25963; /*2 dB steps*/
    }
    for (; c >= 0; c--)
        attenuation[c] = 0;

    adgold->adgold_eeprom[0x00] = 0x00;
    adgold->adgold_eeprom[0x01] = 0x00;
    adgold->adgold_eeprom[0x02] = 0x7f;
    adgold->adgold_eeprom[0x03] = 0x7f;
    adgold->adgold_eeprom[0x04] = 0xf8; /* vol_l */
    adgold->adgold_eeprom[0x05] = 0xf8; /* vol_r */
    adgold->adgold_eeprom[0x06] = 0xf6; /* bass */
    adgold->adgold_eeprom[0x07] = 0xf6; /* treble */
    adgold->adgold_eeprom[0x08] = 0xce;
    adgold->adgold_eeprom[0x09] = 0xff; /* fm_vol_l */
    adgold->adgold_eeprom[0x0a] = 0xff; /* fm_vol_r */
    adgold->adgold_eeprom[0x0b] = 0xff; /* samp_vol_l */
    adgold->adgold_eeprom[0x0c] = 0xff; /* samp_vol_r */
    adgold->adgold_eeprom[0x0d] = 0xff; /* aux_vol_l */
    adgold->adgold_eeprom[0x0e] = 0xff; /* aux_vol_r */
    adgold->adgold_eeprom[0x0f] = 0xff;
    adgold->adgold_eeprom[0x10] = 0xff;
    adgold->adgold_eeprom[0x11] = 0x20;
    adgold->adgold_eeprom[0x12] = 0x00;
    adgold->adgold_eeprom[0x13] = 0x0b; /* IRQ 1, DMA1 */
    adgold->adgold_eeprom[0x14] = 0x00; /* DMA2 */
    adgold->adgold_eeprom[0x15] = 0x71; /* Port */
    adgold->adgold_eeprom[0x16] = 0x00;
    adgold->adgold_eeprom[0x17] = 0x68;
    adgold->adgold_eeprom[0x18] = 0x00; /* Surround */
    adgold->adgold_eeprom[0x19] = 0x00;

    f = nvr_fopen("adgold.bin", "rb");
    if (f) {
        if (fread(adgold->adgold_eeprom, 1, 0x1a, f) != 0x1a)
            fatal("adgold_init(): Error reading data\n");
        fclose(f);
    }

    adgold->adgold_status       = 0xf;
    adgold->adgold_38x_addr     = 0;
    adgold->adgold_eeprom[0x13] = 3 | (1 << 3); /*IRQ 7, DMA 1*/
                                                //        adgold->adgold_eeprom[0x14] = 3 << 4;         /*DMA 3 - Double check this */
    adgold->adgold_eeprom[0x14] = 0x00;         /*DMA ?*/
    adgold->adgold_eeprom[0x15] = 0x388 / 8;    /*Present at 388-38f*/
    memcpy(adgold->adgold_38x_regs, adgold->adgold_eeprom, 0x19);
    adgold->vol_l      = attenuation[adgold->adgold_eeprom[0x04] & 0x3f];
    adgold->vol_r      = attenuation[adgold->adgold_eeprom[0x05] & 0x3f];
    adgold->bass       = adgold->adgold_eeprom[0x06] & 0xf;
    adgold->treble     = adgold->adgold_eeprom[0x07] & 0xf;
    adgold->fm_vol_l   = (int) (int8_t) (adgold->adgold_eeprom[0x09] - 128);
    adgold->fm_vol_r   = (int) (int8_t) (adgold->adgold_eeprom[0x0a] - 128);
    adgold->samp_vol_l = (int) (int8_t) (adgold->adgold_eeprom[0x0b] - 128);
    adgold->samp_vol_r = (int) (int8_t) (adgold->adgold_eeprom[0x0c] - 128);
    adgold->aux_vol_l  = (int) (int8_t) (adgold->adgold_eeprom[0x0d] - 128);
    adgold->aux_vol_r  = (int) (int8_t) (adgold->adgold_eeprom[0x0e] - 128);

    adgold->adgold_mma_enable[0]     = 0;
    adgold->adgold_mma_fifo_start[0] = adgold->adgold_mma_fifo_end[0] = 0;

    /*388/389 are handled by adlib_init*/
    io_sethandler(0x0388, 0x0008, adgold_read, NULL, NULL, adgold_write, NULL, NULL, adgold);

    if (adgold->gameport_enabled)
        gameport_remap(gameport_add(&gameport_201_device), 0x201);

    timer_add(&adgold->adgold_mma_timer_count, adgold_timer_poll, adgold, 1);

    sound_add_handler(adgold_get_buffer, adgold);
    sound_set_cd_audio_filter(adgold_filter_cd_audio, adgold);

    if (device_get_config_int("receive_input"))
        midi_in_handler(1, adgold_input_msg, adgold_input_sysex, adgold);

    return adgold;
}

void
adgold_close(void *p)
{
    FILE     *f;
    adgold_t *adgold = (adgold_t *) p;

    f = nvr_fopen("adgold.bin", "wb");
    if (f) {
        fwrite(adgold->adgold_eeprom, 0x1a, 1, f);
        fclose(f);
    }

    free(adgold);
}

static const device_config_t adgold_config[] = {
// clang-format off
    { "gameport",      "Enable Game port",     CONFIG_BINARY, "",  1 },
    { "surround",      "Surround module",      CONFIG_BINARY, "",  1 },
    { "receive_input", "Receive input (MIDI)", CONFIG_BINARY, "",  1 },
    { "",              "",                                        -1 }
// clang-format on
};

const device_t adgold_device = {
    .name = "AdLib Gold",
    .internal_name = "adlibgold",
    .flags = DEVICE_ISA,
    .local = 0,
    .init = adgold_init,
    .close = adgold_close,
    .reset = NULL,
    { .available = NULL },
    .speed_changed = NULL,
    .force_redraw = NULL,
    .config = adgold_config
};
