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

  machine.c

  Functions to emulate general aspects of the machine (RAM, ROM, interrupts,
  I/O ports)

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

#include "driver.h"
#include "machine/atari_vg.h"
#include "video/avgdvg.h"
#include "asteroid.h"

UINT8 *asteroid_ram1, *asteroid_ram2;

INTERRUPT_GEN( asteroid_interrupt )
{
	/* Turn off interrupts if self-test is enabled */
	if (!(input_port_read(device->machine, "IN0") & 0x80))
		cpu_set_input_line(device, INPUT_LINE_NMI, PULSE_LINE);
}

INTERRUPT_GEN( asterock_interrupt )
{
	/* Turn off interrupts if self-test is enabled */
	if ((input_port_read(device->machine, "IN0") & 0x80))
		cpu_set_input_line(device, INPUT_LINE_NMI, PULSE_LINE);
}

INTERRUPT_GEN( llander_interrupt )
{
	/* Turn off interrupts if self-test is enabled */
	if (input_port_read(device->machine, "IN0") & 0x02)
		cpu_set_input_line(device, INPUT_LINE_NMI, PULSE_LINE);
}

READ8_HANDLER( asteroid_IN0_r )
{
	int res = input_port_read(space->machine, "IN0");
	int bitmask = (1 << offset);

	if (res & bitmask)
		res = 0x80;
	else
		res = ~0x80;

	return res;
}


READ8_HANDLER( asterock_IN0_r )
{
	int res = input_port_read(space->machine, "IN0");
	int bitmask = (1 << offset);

	if (res & bitmask)
		res = ~0x80;
	else
		res = 0x80;

	return res;
}

/*
 * These 7 memory locations are used to read the player's controls.
 * Typically, only the high bit is used. This is handled by one input port.
 */

READ8_HANDLER( asteroid_IN1_r )
{
	int res = input_port_read(space->machine, "IN1");
	int bitmask = (1 << (offset & 0x7));

	if (res & bitmask)
		res = 0x80;
	else
	 	res = ~0x80;

	return res;
}


READ8_HANDLER( asteroid_DSW1_r )
{
	int res;
	int res1;

	res1 = input_port_read(space->machine, "DSW1");

	res = 0xfc | ((res1 >> (2 * (3 - (offset & 0x3)))) & 0x3);
	return res;
}


WRITE8_HANDLER( asteroid_bank_switch_w )
{
	if (data & 4)
	{
		memory_set_bankptr(space->machine, 1, asteroid_ram2);
		memory_set_bankptr(space->machine, 2, asteroid_ram1);
	}
	else
	{
		memory_set_bankptr(space->machine, 1, asteroid_ram1);
		memory_set_bankptr(space->machine, 2, asteroid_ram2);
	}

	set_led_status (0, ~data & 0x02);
	set_led_status (1, ~data & 0x01);
}


WRITE8_HANDLER( astdelux_bank_switch_w )
{
	if (data & 0x80)
	{
		memory_set_bankptr(space->machine, 1, asteroid_ram2);
		memory_set_bankptr(space->machine, 2, asteroid_ram1);
	}
	else
	{
		memory_set_bankptr(space->machine, 1, asteroid_ram1);
		memory_set_bankptr(space->machine, 2, asteroid_ram2);
	}
}


WRITE8_HANDLER( astdelux_led_w )
{
	set_led_status(offset, (data & 0x80) ? 0 : 1);
}


MACHINE_RESET( asteroid )
{
	asteroid_bank_switch_w(cputag_get_address_space(machine, "maincpu", ADDRESS_SPACE_PROGRAM), 0, 0);
	avgdvg_reset_w(cputag_get_address_space(machine, "maincpu", ADDRESS_SPACE_PROGRAM), 0, 0);
}
