/*
 * delaep7x8.c - Cartridge handling, Dela EP7x8kb cart.
 *
 * Written by
 *  Marco van den Heuvel <blackystardust68@yahoo.com>
 *
 * This file is part of VICE, the Versatile Commodore Emulator.
 * See README for copyright notice.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 *  02111-1307  USA.
 *
 */

#include "vice.h"

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

#define CARTRIDGE_INCLUDE_SLOTMAIN_API
#include "c64cartsystem.h"
#undef CARTRIDGE_INCLUDE_SLOTMAIN_API
#include "cartio.h"
#include "cartridge.h"
#include "delaep7x8.h"
#include "export.h"
#include "monitor.h"
#include "snapshot.h"
#include "types.h"
#include "util.h"
#include "crt.h"

/* This eprom system by DELA seems to be a bit more advanced
   than the EP64 and EP256. It can handle what the EP64 can
   handle, plus the following features :

   - Alternate rom at $8000
   - Alternate basic at $A000
   - Extended basic
   - Basic programs
   - Simulated 16kb roms
   - Kernel replacement

   The system uses 8 8kb eproms, of which the first is used for
   the base menu. 7 8kb banks are used for above named features.

   Because of the fact that this system supports switching in a
   different eprom at $8000 (followed by a reset) it is possible
   to place generic 8kb carts (games/tools) in the eproms and
   use them.

   The bank selecting is done by writing to $DE00. Each low bit is used to
   bank in the respective eprom. If all bits are high then  the  EXROM  is
   switched off.

   The bit values for each eprom bank is:

   eprom bank 1 : 11111110 ($FE) (base eprom)
   eprom bank 2 : 11111101 ($FD)
   eprom bank 3 : 11111011 ($FB)
   eprom bank 4 : 11110111 ($F7)
   eprom bank 5 : 11101111 ($EF)
   eprom bank 6 : 11011111 ($DF)
   eprom bank 7 : 10111111 ($BF)
   eprom bank 8 : 01111111 ($7F)

   EXROM off    : 11111111 ($FF)
*/

/* ---------------------------------------------------------------------*/

static int currbank = 0;

static uint8_t regval = 0xfe;

static void delaep7x8_io1_store(uint16_t addr, uint8_t value)
{
    uint8_t bank, config, test_value;

    regval = value;

    /* Each bit of the register set to low activates a
       respective EPROM, $FF switches off EXROM */
    config = (value == 0xff) ? 2 : 0;

    cart_config_changed_slotmain(config, config, CMODE_WRITE);

    bank = 0;
    test_value = (~value);
    while (test_value != 0) {
        bank++;
        test_value = (test_value >> 1);
    }
    if (bank != 0) {
        cart_romlbank_set_slotmain(bank - 1);
        currbank = bank - 1;
    }
}

static uint8_t delaep7x8_io1_peek(uint16_t addr)
{
    return regval;
}

static int delaep7x8_dump(void)
{
    mon_out("Currently active EPROM bank: %d, cart status: %s\n",
            currbank,
            (regval == 0xff) ? "Disabled" : "Enabled");
    return 0;
}

/* ---------------------------------------------------------------------*/

static io_source_t delaep7x8_device = {
    CARTRIDGE_NAME_DELA_EP7x8, /* name of the device */
    IO_DETACH_CART,            /* use cartridge ID to detach the device when involved in a read-collision */
    IO_DETACH_NO_RESOURCE,     /* does not use a resource for detach */
    0xde00, 0xdeff, 0xff,      /* range for the device, address is ignored, reg:$de00, mirrors:$de01-$deff */
    0,                         /* read is never valid, device is write only */
    delaep7x8_io1_store,       /* store function */
    NULL,                      /* NO poke function */
    NULL,                      /* NO read function */
    delaep7x8_io1_peek,        /* peek function */
    delaep7x8_dump,            /* device state information dump function */
    CARTRIDGE_DELA_EP7x8,      /* cartridge ID */
    IO_PRIO_NORMAL,            /* normal priority, device read needs to be checked for collisions */
    0,                         /* insertion order, gets filled in by the registration function */
    IO_MIRROR_NONE             /* NO mirroring */
};

static io_source_list_t *delaep7x8_list_item = NULL;

static const export_resource_t export_res = {
    CARTRIDGE_NAME_DELA_EP7x8, 0, 1, &delaep7x8_device, NULL, CARTRIDGE_DELA_EP7x8
};

/* ---------------------------------------------------------------------*/

void delaep7x8_config_init(void)
{
    cart_config_changed_slotmain(CMODE_8KGAME, CMODE_8KGAME, CMODE_READ);
    cart_romlbank_set_slotmain(0);
}

void delaep7x8_config_setup(uint8_t *rawcart)
{
    memcpy(roml_banks, rawcart, 0x2000 * 8);
    cart_config_changed_slotmain(CMODE_8KGAME, CMODE_8KGAME, CMODE_READ);
    cart_romlbank_set_slotmain(0);
}

/* ---------------------------------------------------------------------*/

static int delaep7x8_common_attach(void)
{
    if (export_add(&export_res) < 0) {
        return -1;
    }
    delaep7x8_list_item = io_source_register(&delaep7x8_device);
    return 0;
}

int delaep7x8_bin_attach(const char *filename, uint8_t *rawcart)
{
    int size = 0x10000;

    memset(rawcart, 0xff, 0x10000);

    while (size != 0) {
        if (util_file_load(filename, rawcart, size, UTIL_FILE_LOAD_SKIP_ADDRESS) < 0) {
            size -= 0x2000;
        } else {
            return delaep7x8_common_attach();
        }
    }
    return -1;
}

int delaep7x8_crt_attach(FILE *fd, uint8_t *rawcart)
{
    crt_chip_header_t chip;

    memset(rawcart, 0xff, 0x10000);

    while (1) {
        if (crt_read_chip_header(&chip, fd)) {
            break;
        }

        if (chip.bank > 7 || chip.size != 0x2000) {
            return -1;
        }

        if (crt_read_chip(rawcart, chip.bank << 13, &chip, fd)) {
            return -1;
        }
    }
    return delaep7x8_common_attach();
}

void delaep7x8_detach(void)
{
    export_remove(&export_res);
    io_source_unregister(delaep7x8_list_item);
    delaep7x8_list_item = NULL;
}

/* ---------------------------------------------------------------------*/

/* CARTDELAEP7X8 snapshot module format:

   type  | name   | version | description
   --------------------------------------
   BYTE  | regval |   0.1   | register
   BYTE  | bank   |   0.0+  | current bank
   ARRAY | ROML   |   0.0+  | 65536 BYTES of ROML data
 */

static const char snap_module_name[] = "CARTDELAEP7X8";
#define SNAP_MAJOR   0
#define SNAP_MINOR   1

int delaep7x8_snapshot_write_module(snapshot_t *s)
{
    snapshot_module_t *m;

    m = snapshot_module_create(s, snap_module_name, SNAP_MAJOR, SNAP_MINOR);

    if (m == NULL) {
        return -1;
    }

    if (0
        || (SMW_B(m, regval) < 0)
        || (SMW_B(m, (uint8_t)currbank) < 0)
        || (SMW_BA(m, roml_banks, 0x2000 * 8) < 0)) {
        snapshot_module_close(m);
        return -1;
    }

    return snapshot_module_close(m);
}

int delaep7x8_snapshot_read_module(snapshot_t *s)
{
    uint8_t vmajor, vminor;
    snapshot_module_t *m;

    m = snapshot_module_open(s, snap_module_name, &vmajor, &vminor);

    if (m == NULL) {
        return -1;
    }

    /* Do not accept versions higher than current */
    if (snapshot_version_is_bigger(vmajor, vminor, SNAP_MAJOR, SNAP_MINOR)) {
        snapshot_set_error(SNAPSHOT_MODULE_HIGHER_VERSION);
        goto fail;
    }

    /* new in 0.1 */
    if (!snapshot_version_is_smaller(vmajor, vminor, 0, 1)) {
        if (SMR_B(m, &regval) < 0) {
            goto fail;
        }
    } else {
        regval = 0;
    }

    if (0
        || (SMR_B_INT(m, &currbank) < 0)
        || (SMR_BA(m, roml_banks, 0x2000 * 8) < 0)) {
        goto fail;
    }

    snapshot_module_close(m);

    return delaep7x8_common_attach();

fail:
    snapshot_module_close(m);
    return -1;
}
