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// license:BSD-3-Clause
// copyright-holders:Nathan Woods
/**********************************************************************

    Motorola 6821 PIA interface and emulation

    Notes:
        * get_port_b_z_mask() gives the caller the bitmask that shows
          which bits are high-impendance when reading port B, and thus
          neither 0 or 1. get_output_cb2_z() returns the same info
          for the CB2 pin.
        * set_port_a_z_mask allows the input callback to indicate
          which port A bits are disconnected. For these bits, the
          read operation will return the output buffer's contents.
        * The 'alt' interface functions are used when the A0 and A1
          address bits are swapped.
        * All 'int' data or return values are bool, and should be
          converted to bool at some point.

**********************************************************************/

#pragma once

#ifndef __6821PIA_H__
#define __6821PIA_H__

#include "emu.h"



/***************************************************************************
    DEVICE CONFIGURATION MACROS
***************************************************************************/

// TODO: REMOVE THESE
#define MCFG_PIA_READPA_HANDLER(_devcb) \
	devcb = &pia6821_device::set_readpa_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_READPB_HANDLER(_devcb) \
	devcb = &pia6821_device::set_readpb_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_READCA1_HANDLER(_devcb) \
	devcb = &pia6821_device::set_readca1_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_READCA2_HANDLER(_devcb) \
	devcb = &pia6821_device::set_readca2_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_READCB1_HANDLER(_devcb) \
	devcb = &pia6821_device::set_readcb1_handler(*device, DEVCB_##_devcb);

// TODO: CONVERT THESE TO WRITE LINE
#define MCFG_PIA_WRITEPA_HANDLER(_devcb) \
	devcb = &pia6821_device::set_writepa_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_WRITEPB_HANDLER(_devcb) \
	devcb = &pia6821_device::set_writepb_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_CA2_HANDLER(_devcb) \
	devcb = &pia6821_device::set_ca2_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_CB2_HANDLER(_devcb) \
	devcb = &pia6821_device::set_cb2_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_IRQA_HANDLER(_devcb) \
	devcb = &pia6821_device::set_irqa_handler(*device, DEVCB_##_devcb);

#define MCFG_PIA_IRQB_HANDLER(_devcb) \
	devcb = &pia6821_device::set_irqb_handler(*device, DEVCB_##_devcb);


/***************************************************************************
    TYPE DEFINITIONS
***************************************************************************/

// ======================> pia6821_device

class pia6821_device :  public device_t
{
public:
	// construction/destruction
	pia6821_device(const machine_config &mconfig, std::string tag, device_t *owner, UINT32 clock);

	// static configuration helpers
	// TODO: REMOVE THESE
	template<class _Object> static devcb_base &set_readpa_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_in_a_handler.set_callback(object); }
	template<class _Object> static devcb_base &set_readpb_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_in_b_handler.set_callback(object); }
	template<class _Object> static devcb_base &set_readca1_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_in_ca1_handler.set_callback(object); }
	template<class _Object> static devcb_base &set_readca2_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_in_ca2_handler.set_callback(object); }
	template<class _Object> static devcb_base &set_readcb1_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_in_cb1_handler.set_callback(object); }

	// TODO: CONVERT THESE TO WRITE LINE
	template<class _Object> static devcb_base &set_writepa_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_out_a_handler.set_callback(object); }
	template<class _Object> static devcb_base &set_writepb_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_out_b_handler.set_callback(object); }

	template<class _Object> static devcb_base &set_ca2_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_ca2_handler.set_callback(object); }
	template<class _Object> static devcb_base &set_cb2_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_cb2_handler.set_callback(object); }
	template<class _Object> static devcb_base &set_irqa_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_irqa_handler.set_callback(object); }
	template<class _Object> static devcb_base &set_irqb_handler(device_t &device, _Object object) { return downcast<pia6821_device &>(device).m_irqb_handler.set_callback(object); }

	DECLARE_READ8_MEMBER( read ) { return reg_r(offset); }
	DECLARE_WRITE8_MEMBER( write ) { reg_w(offset, data); }
	DECLARE_READ8_MEMBER( read_alt ) { return reg_r(((offset << 1) & 0x02) | ((offset >> 1) & 0x01)); }
	DECLARE_WRITE8_MEMBER( write_alt ) { reg_w(((offset << 1) & 0x02) | ((offset >> 1) & 0x01), data); }

	UINT8 port_b_z_mask() const { return ~m_ddr_b; }          // see first note in .c
	void set_port_a_z_mask(UINT8 data) { m_port_a_z_mask = data; }// see second note in .c

	DECLARE_WRITE8_MEMBER( porta_w ) { porta_w(data); }
	void porta_w(UINT8 data);
	void set_a_input(UINT8 data, UINT8 z_mask);
	UINT8 a_output();

	DECLARE_WRITE_LINE_MEMBER( ca1_w );

	DECLARE_WRITE_LINE_MEMBER( ca2_w );
	int ca2_output();
	int ca2_output_z();

	DECLARE_WRITE8_MEMBER( portb_w ) { portb_w(data); }
	void portb_w(UINT8 data);
	UINT8 b_output();

	DECLARE_WRITE_LINE_MEMBER( cb1_w );

	DECLARE_WRITE_LINE_MEMBER( cb2_w );
	int cb2_output();
	int cb2_output_z();

	int irq_a_state() const { return m_irq_a_state; }
	int irq_b_state() const { return m_irq_b_state; }

protected:
	// device-level overrides
	virtual void device_start() override;
	virtual void device_reset() override;

private:
	UINT8 reg_r(UINT8 offset);
	void reg_w(UINT8 offset, UINT8 data);

	void update_interrupts();

	UINT8 get_in_a_value();
	UINT8 get_in_b_value();

	UINT8 get_out_a_value();
	UINT8 get_out_b_value();

	void set_out_ca2(int data);
	void set_out_cb2(int data);

	UINT8 port_a_r();
	UINT8 ddr_a_r();
	UINT8 control_a_r();

	UINT8 port_b_r();
	UINT8 ddr_b_r();
	UINT8 control_b_r();

	void send_to_out_a_func(const char* message);
	void send_to_out_b_func(const char* message);

	void port_a_w(UINT8 data);
	void ddr_a_w(UINT8 data);

	void port_b_w(UINT8 data);
	void ddr_b_w(UINT8 data);

	void control_a_w(UINT8 data);
	void control_b_w(UINT8 data);

	devcb_read8 m_in_a_handler;
	devcb_read8 m_in_b_handler;
	devcb_read_line m_in_ca1_handler;
	devcb_read_line m_in_cb1_handler;
	devcb_read_line m_in_ca2_handler;
	devcb_write8 m_out_a_handler;
	devcb_write8 m_out_b_handler;
	devcb_write_line m_ca2_handler;
	devcb_write_line m_cb2_handler;
	devcb_write_line m_irqa_handler;
	devcb_write_line m_irqb_handler;

	UINT8 m_in_a;
	UINT8 m_in_ca1;
	UINT8 m_in_ca2;
	UINT8 m_out_a;
	UINT8 m_out_ca2;
	UINT8 m_port_a_z_mask;
	UINT8 m_ddr_a;
	UINT8 m_ctl_a;
	UINT8 m_irq_a1;
	UINT8 m_irq_a2;
	UINT8 m_irq_a_state;

	UINT8 m_in_b;
	UINT8 m_in_cb1;
	UINT8 m_in_cb2;
	UINT8 m_out_b;
	UINT8 m_out_cb2;
	UINT8 m_last_out_cb2_z;
	UINT8 m_ddr_b;
	UINT8 m_ctl_b;
	UINT8 m_irq_b1;
	UINT8 m_irq_b2;
	UINT8 m_irq_b_state;

	// variables that indicate if access a line externally -
	// used to for logging purposes ONLY
	bool m_in_a_pushed;
	bool m_out_a_needs_pulled;
	bool m_in_ca1_pushed;
	bool m_in_ca2_pushed;
	bool m_out_ca2_needs_pulled;
	bool m_in_b_pushed;
	bool m_out_b_needs_pulled;
	bool m_in_cb1_pushed;
	bool m_in_cb2_pushed;
	bool m_out_cb2_needs_pulled;
	bool m_logged_port_a_not_connected;
	bool m_logged_port_b_not_connected;
	bool m_logged_ca1_not_connected;
	bool m_logged_ca2_not_connected;
	bool m_logged_cb1_not_connected;
	bool m_logged_cb2_not_connected;
};


// device type definition
extern const device_type PIA6821;


#endif /* __6821PIA_H__ */