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// license:BSD-3-Clause
// copyright-holders:R. Belmont
/***************************************************************************

  Viking 1024x768 fixed-resolution monochrome board

  VRAM from Fs040000 to Fs0517FF
  Read from Fs000000 enables VBL, write to Fs000000 disables VBL
  Write to Fs080000 acks VBL

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

#include "emu.h"
#include "nubus_vikbw.h"
#include "screen.h"

#define VIKBW_SCREEN_NAME   "vikbw_screen"
#define VIKBW_ROM_REGION    "vikbw_rom"

#define VRAM_SIZE   (0x18000)  // 1024x768 @ 1bpp is 98,304 bytes (0x18000)


ROM_START( vikbw )
	ROM_REGION(0x2000, VIKBW_ROM_REGION, 0)
	ROM_LOAD( "viking.bin",   0x000000, 0x002000, CRC(92cf04d1) SHA1(d08349edfc82a0bd5ea848e053e1712092308f74) )
ROM_END

//**************************************************************************
//  GLOBAL VARIABLES
//**************************************************************************

DEFINE_DEVICE_TYPE(NUBUS_VIKBW, nubus_vikbw_device, "nb_vikbw", "Moniterm Viking video card")


//-------------------------------------------------
//  device_add_mconfig - add device configuration
//-------------------------------------------------

MACHINE_CONFIG_START(nubus_vikbw_device::device_add_mconfig)
	MCFG_SCREEN_ADD( VIKBW_SCREEN_NAME, RASTER)
	MCFG_SCREEN_UPDATE_DEVICE(DEVICE_SELF, nubus_vikbw_device, screen_update)
	MCFG_SCREEN_SIZE(1024,768)
	MCFG_SCREEN_VISIBLE_AREA(0, 1024-1, 0, 768-1)
	MCFG_SCREEN_REFRESH_RATE(70)
MACHINE_CONFIG_END

//-------------------------------------------------
//  rom_region - device-specific ROM region
//-------------------------------------------------

const tiny_rom_entry *nubus_vikbw_device::device_rom_region() const
{
	return ROM_NAME( vikbw );
}

//**************************************************************************
//  LIVE DEVICE
//**************************************************************************

//-------------------------------------------------
//  nubus_vikbw_device - constructor
//-------------------------------------------------

nubus_vikbw_device::nubus_vikbw_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
	nubus_vikbw_device(mconfig, NUBUS_VIKBW, tag, owner, clock)
{
}

nubus_vikbw_device::nubus_vikbw_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock) :
	device_t(mconfig, type, tag, owner, clock),
	device_nubus_card_interface(mconfig, *this),
	m_vbl_disable(0)
{
}

//-------------------------------------------------
//  device_start - device-specific startup
//-------------------------------------------------

void nubus_vikbw_device::device_start()
{
	uint32_t slotspace;

	install_declaration_rom(this, VIKBW_ROM_REGION, true);

	slotspace = get_slotspace();

//  printf("[vikbw %p] slotspace = %x\n", this, slotspace);

	m_vram.resize(VRAM_SIZE);
	install_bank(slotspace+0x40000, slotspace+0x40000+VRAM_SIZE-1, "bank_vikbw", &m_vram[0]);
	install_bank(slotspace+0x940000, slotspace+0x940000+VRAM_SIZE-1, "bank_vikbw2", &m_vram[0]);

	nubus().install_device(slotspace, slotspace+3, read32_delegate(FUNC(nubus_vikbw_device::viking_enable_r), this), write32_delegate(FUNC(nubus_vikbw_device::viking_disable_w), this));
	nubus().install_device(slotspace+0x80000, slotspace+0x80000+3, read32_delegate(FUNC(nubus_vikbw_device::viking_ack_r), this), write32_delegate(FUNC(nubus_vikbw_device::viking_ack_w), this));
}

//-------------------------------------------------
//  device_reset - device-specific reset
//-------------------------------------------------

void nubus_vikbw_device::device_reset()
{
	m_vbl_disable = 1;
	memset(&m_vram[0], 0, VRAM_SIZE);

	m_palette[0] = rgb_t(255, 255, 255);
	m_palette[1] = rgb_t(0, 0, 0);
}

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

  Viking 1024x768 B&W card section

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

uint32_t nubus_vikbw_device::screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
{
	uint32_t *scanline;
	int x, y;
	uint8_t pixels;

	if (!m_vbl_disable)
	{
		raise_slot_irq();
	}

	for (y = 0; y < 768; y++)
	{
		scanline = &bitmap.pix32(y);
		for (x = 0; x < 1024/8; x++)
		{
			pixels = m_vram[(y * 128) + (BYTE4_XOR_BE(x))];

			*scanline++ = m_palette[(pixels>>7)&1];
			*scanline++ = m_palette[(pixels>>6)&1];
			*scanline++ = m_palette[(pixels>>5)&1];
			*scanline++ = m_palette[(pixels>>4)&1];
			*scanline++ = m_palette[(pixels>>3)&1];
			*scanline++ = m_palette[(pixels>>2)&1];
			*scanline++ = m_palette[(pixels>>1)&1];
			*scanline++ = m_palette[(pixels&1)];
		}
	}

	return 0;
}

WRITE32_MEMBER( nubus_vikbw_device::viking_ack_w )
{
	lower_slot_irq();
}

READ32_MEMBER( nubus_vikbw_device::viking_ack_r )
{
	return 0;
}

WRITE32_MEMBER( nubus_vikbw_device::viking_disable_w )
{
	m_vbl_disable = 1;
}

READ32_MEMBER( nubus_vikbw_device::viking_enable_r )
{
	m_vbl_disable = 0;
	return 0;
}