/*
 * 86Box	A hypervisor and IBM PC system emulator that specializes in
 *		running old operating systems and software designed for IBM
 *		PC systems and compatibles from 1981 through fairly recent
 *		system designs based on the PCI bus.
 *
 *		This file is part of the 86Box distribution.
 *
 *		Implementation of Ports 61, 62, and 63 used by various
 *		machines.
 *
 * Authors:	Miran Grca, <mgrca8@gmail.com>
 *
 *		Copyright 2021 Miran Grca.
 */
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <86box/86box.h>
#include <86box/device.h>
#include "cpu.h"
#include <86box/timer.h>
#include <86box/io.h>
#include <86box/keyboard.h>
#include <86box/mem.h>
#include <86box/m_xt_xi8088.h>
#include <86box/fdd.h>
#include <86box/fdc.h>
#include <86box/sound.h>
#include <86box/snd_speaker.h>
#include <86box/pit.h>
#include <86box/ppi.h>
#include <86box/video.h>
#include <86box/port_6x.h>


#define PS2_REFRESH_TIME	(16 * TIMER_USEC)

#define PORT_6X_TURBO		1
#define PORT_6X_EXT_REF		2
#define PORT_6X_MIRROR		4
#define PORT_6X_SWA		8


static void
port_6x_write(uint16_t port, uint8_t val, void *priv)
{
    port_6x_t *dev = (port_6x_t *) priv;

    port &= 3;

    if ((port == 3) && (dev->flags & PORT_6X_MIRROR))
	port = 1;

    switch (port) {
	case 1:
		ppi.pb = (ppi.pb & 0x10) | (val & 0x0f);

		speaker_update();
		speaker_gated = val & 1;
		speaker_enable = val & 2;
		if (speaker_enable) 
			was_speaker_enable = 1;
		pit_ctr_set_gate(&pit->counters[2], val & 1);

		if (dev->flags & PORT_6X_TURBO)
			xi8088_turbo_set(!!(val & 0x04));
		break;
    }
}


static uint8_t
port_6x_read(uint16_t port, void *priv)
{
    port_6x_t *dev = (port_6x_t *) priv;
    uint8_t ret = 0xff;

    port &= 3;

    if ((port == 3) && (dev->flags & PORT_6X_MIRROR))
	port = 1;

    switch (port) {
	case 1:
		if (dev->flags & PORT_6X_EXT_REF) {
		    	ret = ppi.pb & 0x0f;

			if (dev->refresh)
				ret |= 0x10;
		} else
			ret = ppi.pb & 0x1f;

		if (ppispeakon)
			ret |= 0x20;

		if (dev->flags & PORT_6X_TURBO)
			ret = (ret & 0xfb) | (xi8088_turbo_get() ? 0x04 : 0x00);
		break;
	case 2:
		if (dev->flags & PORT_6X_SWA) {
			/* SWA on Olivetti M240 mainboard (off=1) */
			ret = 0x00;
			if (ppi.pb & 0x8) {
				/* Switches 4, 5 - floppy drives (number) */
				int i, fdd_count = 0;
				for (i = 0; i < FDD_NUM; i++) {
				    if (fdd_get_flags(i))
				        fdd_count++;
				}
				if (!fdd_count)
					ret |= 0x00;
				else
					ret |= ((fdd_count - 1) << 2);
				/* Switches 6, 7 - monitor type */
				if (video_is_mda())
					ret |= 0x3;
				else if (video_is_cga())
					ret |= 0x2;	/* 0x10 would be 40x25 */
				else
					ret |= 0x0;
			} else {
				/* bit 2 always on */
				ret |= 0x4;
				/* Switch 8 - 8087 FPU. */
				if (hasfpu)
					ret |= 0x02;
			}
		}
		break;
    }

    return(ret);
}


static void
port_6x_refresh(void *priv)
{
    port_6x_t *dev = (port_6x_t *) priv;

    dev->refresh = !dev->refresh;
    timer_advance_u64(&dev->refresh_timer, PS2_REFRESH_TIME);
}


static void
port_6x_close(void *priv)
{
    port_6x_t *dev = (port_6x_t *) priv;

    timer_disable(&dev->refresh_timer);

    free(dev);
}


void *
port_6x_init(const device_t *info)
{
    port_6x_t *dev = (port_6x_t *) malloc(sizeof(port_6x_t));
    memset(dev, 0, sizeof(port_6x_t));

    dev->flags = info->local & 0xff;

    io_sethandler(0x0061, 3, port_6x_read, NULL, NULL, port_6x_write, NULL, NULL, dev);

    if (dev->flags & PORT_6X_EXT_REF)
	timer_add(&dev->refresh_timer, port_6x_refresh, dev, 1);

    return dev;
}


const device_t port_6x_device = {
    "Port 6x Registers",
    0,
    0,
    port_6x_init, port_6x_close, NULL,
    { NULL }, NULL, NULL,
    NULL
};


const device_t port_6x_xi8088_device = {
    "Port 6x Registers (Xi8088)",
    0,
    PORT_6X_TURBO | PORT_6X_EXT_REF | PORT_6X_MIRROR,
    port_6x_init, port_6x_close, NULL,
    { NULL }, NULL, NULL,
    NULL
};


const device_t port_6x_ps2_device = {
    "Port 6x Registers (IBM PS/2)",
    0,
    PORT_6X_EXT_REF,
    port_6x_init, port_6x_close, NULL,
    { NULL }, NULL, NULL,
    NULL
};


const device_t port_6x_olivetti_device = {
    "Port 6x Registers (Olivetti)",
    0,
    PORT_6X_SWA,
    port_6x_init, port_6x_close, NULL,
    { NULL }, NULL, NULL,
    NULL
};