// License: BSD-3-Clause
// Author: Brandon Munger
/******************************************************************************
*
* Rolm CBX 9751 Release 9005 Driver 
* This driver attempts to emulate the following models:
* * Model 10
* * Model 40
*
* The basis of this driver uses the zexall.c driver by Jonathan Gevaryahu and Robbbert
* Memory map:
* * 0x08000000 - 0x0800ffff : PROM Region(?)
******************************************************************************/

/* Core includes */
#include "emu.h"
#include "cpu/m68000/m68000.h"
#include "machine/terminal.h"

#define TERMINAL_TAG "terminal"

class r9751_state : public driver_device
{
public:
	r9751_state(const machine_config &mconfig, device_type type, const char *tag)
		: driver_device(mconfig, type, tag),
		m_maincpu(*this, "maincpu"),
		m_terminal(*this, TERMINAL_TAG),
		m_main_ram(*this, "main_ram")
	{
	}

	DECLARE_READ8_MEMBER( r9751_output_ack_r );
	DECLARE_READ8_MEMBER( r9751_output_req_r );
	DECLARE_READ8_MEMBER( r9751_output_data_r );
	DECLARE_WRITE8_MEMBER( r9751_output_ack_w );
	DECLARE_WRITE8_MEMBER( r9751_output_req_w );
	DECLARE_WRITE8_MEMBER( r9751_output_data_w );
	DECLARE_DRIVER_INIT(r9751);
private:
	required_device<cpu_device> m_maincpu;
	required_device<generic_terminal_device> m_terminal;
	required_shared_ptr<UINT32> m_main_ram;
	UINT8 m_out_data; // byte written to 0xFFFF
	UINT8 m_out_req; // byte written to 0xFFFE
	UINT8 m_out_req_last; // old value at 0xFFFE before the most recent write
	UINT8 m_out_ack; // byte written to 0xFFFC
	virtual void machine_reset();
};

DRIVER_INIT_MEMBER(r9751_state,r9751)
{
	m_out_ack = 0;
	m_out_req = 0;
	m_out_req_last = 0;
	m_out_data = 0;
}

void r9751_state::machine_reset()
{
// rom is self-modifying, so need to refresh it on each run
	//UINT8 *rom = memregion("prom")->base();
	//UINT8 *ram = m_main_ram;
	/* fill main ram with r9751 code */
	//memcpy(ram, rom, 0x228a);
}

READ8_MEMBER( r9751_state::r9751_output_ack_r )
{
// spit out the byte in out_byte if out_req is not equal to out_req_last
	if (m_out_req != m_out_req_last)
	{
		m_terminal->write(space,0,m_out_data);
		fprintf(stderr,"%c",m_out_data);
		m_out_req_last = m_out_req;
		m_out_ack++;
	}
	return m_out_ack;
}

WRITE8_MEMBER( r9751_state::r9751_output_ack_w )
{
	m_out_ack = data;
}

READ8_MEMBER( r9751_state::r9751_output_req_r )
{
	return m_out_req;
}

WRITE8_MEMBER( r9751_state::r9751_output_req_w )
{
	m_out_req_last = m_out_req;
	m_out_req = data;
}

READ8_MEMBER( r9751_state::r9751_output_data_r )
{
	return m_out_data;
}

WRITE8_MEMBER( r9751_state::r9751_output_data_w )
{
	m_out_data = data;
}

/******************************************************************************
 Address Maps
******************************************************************************/

static ADDRESS_MAP_START(r9751_mem, AS_PROGRAM, 32, r9751_state)
	ADDRESS_MAP_UNMAP_HIGH
	//AM_RANGE(0x0000, 0xfffc) AM_RAM AM_SHARE("main_ram")
	//AM_RANGE(0xfffd, 0xfffd) AM_READWRITE(r9751_output_ack_r,r9751_output_ack_w)
	//AM_RANGE(0xfffe, 0xfffe) AM_READWRITE(r9751_output_req_r,r9751_output_req_w)
	//AM_RANGE(0xffff, 0xffff) AM_READWRITE(r9751_output_data_r,r9751_output_data_w)

	//AM_RANGE(0x00000000,0x0000ffff) AM_ROM AM_REGION("prom",0)
	AM_RANGE(0x00020000,0x00ffffff) AM_RAM AM_SHARE("main_ram") // 16MB
	AM_RANGE(0x08000000,0x0800ffff) AM_ROM AM_REGION("prom", 0)
ADDRESS_MAP_END

static ADDRESS_MAP_START(r9751_io, AS_IO, 32, r9751_state)
	ADDRESS_MAP_UNMAP_HIGH
	//AM_RANGE(0x0001, 0x0001) AM_NOP // really a disable/enable for some sort of interrupt timer on kev's hardware, which is completely irrelevant for the r9751 test
ADDRESS_MAP_END


/******************************************************************************
 Input Ports
******************************************************************************/
static INPUT_PORTS_START( r9751 )
INPUT_PORTS_END

/******************************************************************************
 Machine Drivers
******************************************************************************/

static MACHINE_CONFIG_START( r9751, r9751_state )
	/* basic machine hardware */
	MCFG_CPU_ADD("maincpu", M68030, 20000000)
	MCFG_CPU_PROGRAM_MAP(r9751_mem)
	MCFG_CPU_IO_MAP(r9751_io)
	MCFG_QUANTUM_TIME(attotime::from_hz(60))

	/* video hardware */
	MCFG_DEVICE_ADD(TERMINAL_TAG, GENERIC_TERMINAL, 0)
MACHINE_CONFIG_END



/******************************************************************************
 ROM Definitions
******************************************************************************/

ROM_START(r9751)
	//ROM_REGION(0x08000000, "prom", 0)
	ROM_REGION(0x00010000, "prom", 0)
	//ROM_LOAD("zex.bin", 0x0000, 0x2289, CRC(77e0a1df) SHA1(cc8f84724e3837783816d92a6dfb8e5975232c66))
	ROM_SYSTEM_BIOS(0, "prom34",  "PROM Version 3.4")
	ROMX_LOAD( "PROM.9751.9005.V3.4.PN98D4643.bin", 0x0000, 0x10000, CRC(9fb19a85) SHA1(c861e15a2fc9a4ef689c2034c53fbb36f17f7da6),ROM_GROUPWORD | ROM_BIOS(1) )
ROM_END



/******************************************************************************
 Drivers
******************************************************************************/

/*    YEAR  NAME        PARENT      COMPAT  MACHINE     INPUT   INIT      COMPANY                     FULLNAME                                                    FLAGS */
COMP( 198?, r9751,   0,          0,      r9751,   r9751, r9751_state, r9751,      "ROLM Systems, Inc.",   "ROLM 9751 Release 9005", GAME_NO_SOUND | GAME_NOT_WORKING )