/**

 * $Id$

 * 

 * "Fake" BIOS functions, for operation without the actual BIOS.

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

 * 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.

 */

#include "dream.h"

#include "mem.h"

#include "syscall.h"

#include "dreamcast.h"

#include "sh4/sh4.h"

#define COMMAND_QUEUE_LENGTH 16

/* TODO: Check if these are the real ATAPI command codes or not */

#define GD_CMD_PIOREAD     16

#define GD_CMD_DMAREAD     17

#define GD_CMD_GETTOC      18

#define GD_CMD_GETTOC2     19

#define GD_CMD_PLAY        20

#define GD_CMD_PLAY2       21

#define GD_CMD_PAUSE       22

#define GD_CMD_RELEASE     23

#define GD_CMD_INIT        24

#define GD_CMD_SEEK        27

#define GD_CMD_READ        28

#define GD_CMD_STOP        33

#define GD_CMD_GETSCD      34

#define GD_CMD_GETSES      35

#define GD_CMD_STATUS_NONE 0

#define GD_CMD_STATUS_ACTIVE 1

#define GD_CMD_STATUS_DONE 2

#define GD_CMD_STATUS_ABORT 3

#define GD_CMD_STATUS_ERROR 4

#define GD_ERROR_OK          0

#define GD_ERROR_NO_DISC     2

#define GD_ERROR_DISC_CHANGE 6

#define GD_ERROR_SYSTEM      1

typedef struct gdrom_command {

    int status;

    uint32_t cmd_code;

    sh4ptr_t data;

    uint32_t result[4];

} *gdrom_command_t;

static struct gdrom_command gdrom_cmd_queue[COMMAND_QUEUE_LENGTH];

static struct bios_gdrom_status {

    uint32_t status;

    uint32_t disk_type;

} bios_gdrom_status;

void bios_gdrom_run_command( gdrom_command_t cmd )

{

    DEBUG( "BIOS GD command %d", cmd->cmd_code );

    switch( cmd->cmd_code ) {

    case GD_CMD_INIT:

	/* *shrug* */

	cmd->status = GD_CMD_STATUS_DONE;

	break;

    default:

	cmd->status = GD_CMD_STATUS_ERROR;

	cmd->result[0] = GD_ERROR_SYSTEM;

	break;

    }

}

void bios_gdrom_init( void )

{

    memset( &gdrom_cmd_queue, 0, sizeof(gdrom_cmd_queue) );

}

uint32_t bios_gdrom_enqueue( uint32_t cmd, sh4ptr_t ptr )

{

    int i;

    for( i=0; i<COMMAND_QUEUE_LENGTH; i++ ) {

	if( gdrom_cmd_queue[i].status != GD_CMD_STATUS_ACTIVE ) {

	    gdrom_cmd_queue[i].status = GD_CMD_STATUS_ACTIVE;

	    gdrom_cmd_queue[i].cmd_code = cmd;

	    gdrom_cmd_queue[i].data = ptr;

	    return i;

	}

    }

    return -1;

}

void bios_gdrom_run_queue( void ) 

{

    int i;

    for( i=0; i<COMMAND_QUEUE_LENGTH; i++ ) {

	if( gdrom_cmd_queue[i].status == GD_CMD_STATUS_ACTIVE ) {

	    bios_gdrom_run_command( &gdrom_cmd_queue[i] );

	}

    }

}

gdrom_command_t bios_gdrom_get_command( uint32_t id )

{

    if( id >= COMMAND_QUEUE_LENGTH ||

	gdrom_cmd_queue[id].status == GD_CMD_STATUS_NONE )

	return NULL;

    return &gdrom_cmd_queue[id];

}

/**

 * Syscall list courtesy of Marcus Comstedt

 */

void bios_syscall( uint32_t syscallid )

{

    gdrom_command_t cmd;

    switch( syscallid ) {

    case 0xB0: /* sysinfo */

	break;

    case 0xB4: /* Font */

	break;

    case 0xB8: /* Flash */

	break;

    case 0xBC: /* Misc/GD-Rom */

	switch( sh4r.r[6] ) {

	case 0: /* GD-Rom */

	    switch( sh4r.r[7] ) {

	    case 0: /* Send command */

		if( sh4r.r[5] == 0 )

		    sh4r.r[0] = bios_gdrom_enqueue( sh4r.r[4], NULL );

		else

		    sh4r.r[0] = bios_gdrom_enqueue( sh4r.r[4], mem_get_region(sh4r.r[5]) );

		break;

	    case 1:  /* Check command */

		cmd = bios_gdrom_get_command( sh4r.r[4] );

		if( cmd == NULL ) {

		    sh4r.r[0] = GD_CMD_STATUS_NONE;

		} else {

		    sh4r.r[0] = cmd->status;

		    if( cmd->status == GD_CMD_STATUS_ERROR &&

			sh4r.r[5] != 0 ) {

			mem_copy_to_sh4( sh4r.r[5], (sh4ptr_t)&cmd->result, sizeof(cmd->result) );

		    }

		}

		break;

	    case 2: /* Mainloop */

		bios_gdrom_run_queue();

		break;

	    case 3: /* Init */

		bios_gdrom_init();

		break;

	    case 4: /* Drive status */

		if( sh4r.r[4] != 0 ) {

		    mem_copy_to_sh4( sh4r.r[4], (sh4ptr_t)&bios_gdrom_status, 

				      sizeof(bios_gdrom_status) );

		}

		sh4r.r[0] = 0;

		break;

	    case 8: /* Abort command */

		cmd = bios_gdrom_get_command( sh4r.r[4] );

		if( cmd == NULL || cmd->status != GD_CMD_STATUS_ACTIVE ) {

		    sh4r.r[0] = -1;

		} else {

		    cmd->status = GD_CMD_STATUS_ABORT;

		    sh4r.r[0] = 0;

		}

		break;

	    case 9: /* Reset */

		break;

	    case 10: /* Set mode */

		sh4r.r[0] = 0;

		break;

	    }

	    break;

	case -1: /* Misc */

	    break;

	default: /* ??? */

	    break;

	}

	break;

    case 0xE0: /* Menu */

	switch( sh4r.r[7] ) {

	case 0:

	    WARN( "Entering main program" );

	    break;

	case 1:

	    WARN( "Program aborted to DC menu");

	    dreamcast_stop();

	    break;

	}

    }

}

void bios_install( void ) 

{

    bios_gdrom_init();

    syscall_add_hook_vector( 0xB0, 0x8C0000B0, bios_syscall );

    syscall_add_hook_vector( 0xB4, 0x8C0000B4, bios_syscall );

    syscall_add_hook_vector( 0xB8, 0x8C0000B8, bios_syscall );

    syscall_add_hook_vector( 0xBC, 0x8C0000BC, bios_syscall );

    syscall_add_hook_vector( 0xE0, 0x8C0000E0, bios_syscall );

}