/**

  * $Id: bios.c,v 1.2 2006-03-13 12:38:34 nkeynes Exp $

  * 

  * "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 "sh4/sh4core.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;

     char *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, char *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], &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], &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 );

 }