/*
  Hatari - bios.c

  This file is distributed under the GNU Public License, version 2 or at
  your option any later version. Read the file gpl.txt for details.

  Bios Handler (Trap #13)

  We intercept and direct some Bios calls to handle input/output to RS-232
  or the printer etc...
*/
const char Bios_rcsid[] = "Hatari $Id: bios.c,v 1.10 2007/01/16 18:42:59 thothy Exp $";

#include "main.h"
#include "configuration.h"
#include "floppy.h"
#include "log.h"
#include "m68000.h"
#include "misc.h"
#include "printer.h"
#include "rs232.h"
#include "stMemory.h"
#include "bios.h"


#define BIOS_DEBUG 0


/*-----------------------------------------------------------------------*/
/**
 * BIOS Return input device status
 * Call 1
 */
static BOOL Bios_Bconstat(Uint32 Params)
{
	Uint16 Dev;

	Dev = STMemory_ReadWord(Params+SIZE_WORD);

	switch(Dev)
	{
	 case 0:                            /* PRT: Centronics */
		if (ConfigureParams.Printer.bEnablePrinting)
		{
			Regs[REG_D0] = 0;               /* No characters ready (cannot read from printer) */
			return TRUE;
		}
		else
		{
			return FALSE;
		}
		break;
	 case 1:                            /* AUX: RS-232 */
		if (ConfigureParams.RS232.bEnableRS232)
		{
			if (RS232_GetStatus())
				Regs[REG_D0] = -1;      /* Chars waiting */
			else
				Regs[REG_D0] = 0;
			return TRUE;
		}
		else
		{
			return FALSE;
		}
		break;
	}

	return FALSE;
}


/*-----------------------------------------------------------------------*/
/**
 * BIOS Read character from device
 * Call 2
 */
static BOOL Bios_Bconin(Uint32 Params)
{
	Uint16 Dev;
	unsigned char Char;

	Dev = STMemory_ReadWord(Params+SIZE_WORD);

	switch(Dev)
	{
	 case 0:                            /* PRT: Centronics */
		if (ConfigureParams.Printer.bEnablePrinting)
		{
			Regs[REG_D0] = 0;           /* Force NULL character (cannot read from printer) */
			return TRUE;
		}
		else
		{
			return FALSE;
		}
		break;
	 case 1:                            /* AUX: RS-232 */
		if (ConfigureParams.RS232.bEnableRS232)
		{
			RS232_ReadBytes(&Char, 1);
			Regs[REG_D0] = Char;
			return TRUE;
		}
		else
		{
			return FALSE;
		}
		break;
	}

	return FALSE;
}


/*-----------------------------------------------------------------------*/
/**
 * BIOS Write character to device
 * Call 3
 */
static BOOL Bios_Bconout(Uint32 Params)
{
	Uint16 Dev;
	unsigned char Char;

	Dev = STMemory_ReadWord(Params+SIZE_WORD);
	Char = STMemory_ReadWord(Params+SIZE_WORD+SIZE_WORD);

	switch(Dev)
	{
	 case 0:                            /* PRT: Centronics */
		if (ConfigureParams.Printer.bEnablePrinting)
		{
			Printer_TransferByteTo(Char);
			return TRUE;
		}
		else
		{
			return FALSE;
		}
		break;
	 case 1:                            /* AUX: RS-232 */
		if (ConfigureParams.RS232.bEnableRS232)
		{
			RS232_TransferBytesTo(&Char, 1);
			return TRUE;
		}
		else
		{
			return FALSE;
		}
		break;
	}

	return FALSE;
}


/*-----------------------------------------------------------------------*/
/**
 * BIOS Read/Write disk sector
 * Call 4
 */
static BOOL Bios_RWabs(Uint32 Params)
{
#if BIOS_DEBUG
	Uint32 pBuffer;
	Uint16 RWFlag, Number, RecNo, Dev;

	/* Read details from stack */
	RWFlag = STMemory_ReadWord(Params+SIZE_WORD);
	pBuffer = STMemory_ReadLong(Params+SIZE_WORD+SIZE_WORD);
	Number = STMemory_ReadWord(Params+SIZE_WORD+SIZE_WORD+SIZE_LONG);
	RecNo = STMemory_ReadWord(Params+SIZE_WORD+SIZE_WORD+SIZE_LONG+SIZE_WORD);
	Dev = STMemory_ReadWord(Params+SIZE_WORD+SIZE_WORD+SIZE_LONG+SIZE_WORD+SIZE_WORD);

	Log_Printf(LOG_DEBUG, "RWABS %s,%d,0x%X,%d,%d\n", EmulationDrives[Dev].szFileName,RWFlag, (char *)STRAM_ADDR(pBuffer), RecNo, Number);
#endif

	return FALSE;
}


/*-----------------------------------------------------------------------*/
/**
 * BIOS Return output device status
 * Call 8
 */
static BOOL Bios_Bcostat(Uint32 Params)
{
	Uint16 Dev;

	Dev = STMemory_ReadWord(Params+SIZE_WORD);

	switch(Dev)
	{
	 case 0:                            /* PRT: Centronics */
		if (ConfigureParams.Printer.bEnablePrinting)
		{
			Regs[REG_D0] = -1;          /* Device ready */
			return TRUE;
		}
		else
		{
			return FALSE;
		}
		break;
	 case 1:                            /* AUX: RS-232 */
		if (ConfigureParams.RS232.bEnableRS232)
		{
			Regs[REG_D0] = -1;          /* Device ready */
			return TRUE;
		}
		else
		{
			return FALSE;
		}
		break;
	}

	return FALSE;
}


/*-----------------------------------------------------------------------*/
/**
 * Check Bios call and see if we need to re-direct to our own routines
 * Return TRUE if we've handled the exception, else return FALSE to let TOS attempt it
 */
BOOL Bios(void)
{
	Uint32 Params;
	Uint16 BiosCall;

	/* Get call */
	Params = Regs[REG_A7];
	BiosCall = STMemory_ReadWord(Params);

	/* Debug_File("BIOS %d\n",BiosCall); */

	/* Intercept? */
	switch(BiosCall)
	{
	 case 0x1:
		return Bios_Bconstat(Params);
	 case 0x2:
		return Bios_Bconin(Params);
	 case 0x3:
		return Bios_Bconout(Params);
	 case 0x4:
		return Bios_RWabs(Params);
	 case 0x8:
		return Bios_Bcostat(Params);
	 default:           /* Call as normal! */
		return FALSE;
	}
}