/*
 * 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 the OPTi 82C291 chipset.
 *
 * Authors: plant/nerd73, Tiseno100
 *
 *          Copyright 2020 plant/nerd73.
 *          Copyright 2021 Tiseno100.
 */
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#define HAVE_STDARG_H
#include <86box/86box.h>
#include "cpu.h"
#include <86box/timer.h>
#include <86box/io.h>
#include <86box/device.h>
#include <86box/mem.h>
#include <86box/plat_unused.h>
#include <86box/port_92.h>
#include <86box/chipset.h>

#ifdef ENABLE_OPTI291_LOG
int opti291_do_log = ENABLE_OPTI291_LOG;

static void
opti291_log(const char *fmt, ...)
{
    va_list ap;

    if (opti291_do_log) {
        va_start(ap, fmt);
        pclog_ex(fmt, ap);
        va_end(ap);
    }
}
#else
#    define opti291_log(fmt, ...)
#endif

typedef struct opti291_t {
    uint8_t    index;
    uint8_t    regs[256];
    port_92_t *port_92;
} opti291_t;

static void
opti291_recalc(opti291_t *dev)
{
    mem_set_mem_state_both(0xf0000, 0x10000, (!(dev->regs[0x23] & 0x40) ? MEM_READ_INTERNAL : MEM_READ_EXTANY) | ((dev->regs[0x27] & 0x80) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL));

    for (uint32_t i = 0; i < 4; i++) {
        mem_set_mem_state_both(0xc0000 + (i << 14), 0x4000, ((dev->regs[0x26] & (1 << (i + 4))) ? MEM_READ_INTERNAL : MEM_READ_EXTANY) | ((dev->regs[0x27] & 0x10) ? MEM_WRITE_DISABLED : ((dev->regs[0x26] & (1 << i)) ? MEM_WRITE_INTERNAL : MEM_WRITE_EXTANY)));
        mem_set_mem_state_both(0xd0000 + (i << 14), 0x4000, ((dev->regs[0x25] & (1 << (i + 4))) ? MEM_READ_INTERNAL : MEM_READ_EXTANY) | ((dev->regs[0x27] & 0x20) ? MEM_WRITE_DISABLED : ((dev->regs[0x25] & (1 << i)) ? MEM_WRITE_INTERNAL : MEM_WRITE_EXTANY)));
        mem_set_mem_state_both(0xe0000 + (i << 14), 0x4000, ((dev->regs[0x24] & (1 << (i + 4))) ? MEM_READ_INTERNAL : MEM_READ_EXTANY) | ((dev->regs[0x27] & 0x40) ? MEM_WRITE_DISABLED : ((dev->regs[0x24] & (1 << i)) ? MEM_WRITE_INTERNAL : MEM_WRITE_EXTANY)));
    }
    flushmmucache();
}
static void
opti291_write(uint16_t addr, uint8_t val, void *priv)
{
    opti291_t *dev = (opti291_t *) priv;

    switch (addr) {
        case 0x22:
            dev->index = val;
            break;
        case 0x24:
            opti291_log("OPTi 291: dev->regs[%02x] = %02x\n", dev->index, val);
            switch (dev->index) {
                case 0x20:
                    dev->regs[dev->index] = val & 0x3f;
                    break;
                case 0x21:
                    dev->regs[dev->index] = val & 0xf3;
                    break;
                case 0x22:
                    dev->regs[dev->index] = val;
                    break;
                case 0x23:
                case 0x24:
                case 0x25:
                case 0x26:
                    dev->regs[dev->index] = val;
                    opti291_recalc(dev);
                    break;
                case 0x27:
                case 0x28:
                    dev->regs[dev->index] = val;
                    break;
                case 0x29:
                    dev->regs[dev->index] = val & 0x0f;
                    break;
                case 0x2a:
                case 0x2b:
                case 0x2c:
                    dev->regs[dev->index] = val;
                    break;

                default:
                    break;
            }
            break;

        default:
            break;
    }
}

static uint8_t
opti291_read(uint16_t addr, void *priv)
{
    const opti291_t *dev = (opti291_t *) priv;

    return (addr == 0x24) ? dev->regs[dev->index] : 0xff;
}

static void
opti291_close(void *priv)
{
    opti291_t *dev = (opti291_t *) priv;

    free(dev);
}

static void *
opti291_init(UNUSED(const device_t *info))
{
    opti291_t *dev = (opti291_t *) calloc(1, sizeof(opti291_t));

    io_sethandler(0x022, 0x0001, opti291_read, NULL, NULL, opti291_write, NULL, NULL, dev);
    io_sethandler(0x024, 0x0001, opti291_read, NULL, NULL, opti291_write, NULL, NULL, dev);
    dev->regs[0x22] = 0xf0;
    dev->regs[0x23] = 0x40;
    dev->regs[0x28] = 0x08;
    dev->regs[0x29] = 0xa0;
    device_add(&port_92_device);
    opti291_recalc(dev);

    return dev;
}

const device_t opti291_device = {
    .name          = "OPTi 82C291",
    .internal_name = "opti291",
    .flags         = 0,
    .local         = 0,
    .init          = opti291_init,
    .close         = opti291_close,
    .reset         = NULL,
    .available     = NULL,
    .speed_changed = NULL,
    .force_redraw  = NULL,
    .config        = NULL
};
