// license:BSD-3-Clause
// copyright-holders:Curt Coder
#include "includes/pc1512.h"
//**************************************************************************
// CONSTANTS
//**************************************************************************
#define LOG 0
static const rgb_t PALETTE[] =
{
RGB_BLACK,
MAKE_RGB(0x00, 0x00, 0xaa),
MAKE_RGB(0x00, 0xaa, 0x00),
MAKE_RGB(0x00, 0xaa, 0xaa),
MAKE_RGB(0xaa, 0x00, 0x00),
MAKE_RGB(0xaa, 0x00, 0xaa),
MAKE_RGB(0xaa, 0x55, 0x00),
MAKE_RGB(0xaa, 0xaa, 0xaa),
MAKE_RGB(0x55, 0x55, 0x55),
MAKE_RGB(0x55, 0x55, 0xff),
MAKE_RGB(0x55, 0xff, 0x55),
MAKE_RGB(0x55, 0xff, 0xff),
MAKE_RGB(0xff, 0x55, 0x55),
MAKE_RGB(0xff, 0x55, 0xff),
MAKE_RGB(0xff, 0xff, 0x55),
RGB_WHITE
};
static const int PALETTE_0[] = { 0, 3, 5, 7 };
static const int PALETTE_1[] = { 0, 2, 4, 6 };
static const int PALETTE_2[] = { 0, 3, 4, 7 };
enum
{
ALPHA_40 = 0,
ALPHA_80,
GRAPHICS_1,
GRAPHICS_2
};
#define MODE_ALPHA_80 0x01
#define MODE_GRAPHICS 0x02
#define MODE_PALETTE_2 0x04
#define MODE_ENABLE_VIDEO 0x08
#define MODE_GRAPHICS_2 0x10
#define MODE_BLINK 0x20
#define COLOR_INTENSITY 0x10
#define COLOR_PALETTE_1 0x20
#define VFP_HIRES 22
#define HFP_HIRES 112
#define VFP_LORES 22
#define HFP_LORES 16
//**************************************************************************
// VIDEO RAM ACCESS
//**************************************************************************
//-------------------------------------------------
// video_ram_r -
//-------------------------------------------------
READ8_MEMBER( pc1512_state::video_ram_r )
{
UINT8 data = 0;
switch (get_display_mode(m_vdu_mode))
{
case ALPHA_40:
case ALPHA_80:
data = m_video_ram[offset];
break;
case GRAPHICS_1:
data = m_video_ram[(offset << 2) | 3];
break;
case GRAPHICS_2:
data = m_video_ram[(offset << 2) | (m_vdu_rdsel ^ 0x03)];
break;
}
return data;
}
//-------------------------------------------------
// video_ram_w -
//-------------------------------------------------
WRITE8_MEMBER( pc1512_state::video_ram_w )
{
switch (get_display_mode(m_vdu_mode))
{
case ALPHA_40:
case ALPHA_80:
m_video_ram[offset] = data;
break;
case GRAPHICS_1:
m_video_ram[(offset << 2) | 3] = data;
m_video_ram[(offset << 2) | 2] = data;
m_video_ram[(offset << 2) | 1] = data;
m_video_ram[(offset << 2) | 0] = data;
break;
case GRAPHICS_2:
if (BIT(m_vdu_plane, 0)) m_video_ram[(offset << 2) | 3] = data;
if (BIT(m_vdu_plane, 1)) m_video_ram[(offset << 2) | 2] = data;
if (BIT(m_vdu_plane, 2)) m_video_ram[(offset << 2) | 1] = data;
if (BIT(m_vdu_plane, 3)) m_video_ram[(offset << 2) | 0] = data;
break;
}
}
//-------------------------------------------------
// vdu_r -
//-------------------------------------------------
READ8_MEMBER( pc1512_state::vdu_r )
{
UINT8 data = 0;
switch (offset)
{
case 1: case 3: case 5: case 7:
data = m_vdu->register_r(space, 0);
break;
case 0xa: // VDU Status
/*
bit description
0 Toggle Bit
1 Light-pen latch select
2 Light-pen switch off
3 Frame Flyback Time
4
5
6
7
*/
// toggle bit
data |= m_toggle;
m_toggle = !m_toggle;
// light pen latch
data |= m_lpen << 1;
// light pen switch
data |= 0x04;
// vertical sync
int flyback = 0;
if (machine().primary_screen->vpos() < VFP_LORES - 16) flyback = 1;
if (machine().primary_screen->vpos() > VFP_LORES + 200) flyback = 1;
data |= flyback << 3;
break;
}
return data;
}
//-------------------------------------------------
// vdu_w -
//-------------------------------------------------
WRITE8_MEMBER( pc1512_state::vdu_w )
{
switch (offset)
{
case 0: case 2: case 4: case 6:
m_vdu->address_w(space, 0, data);
break;
case 1: case 3: case 5: case 7:
m_vdu->register_w(space, 0, data);
break;
case 8: // VDU Mode Control
/*
bit description
0 Select Alpha 80 Char mode (de-select 40 Char mode)
1 Select Graphics modes (de-select Alpha modes)
2 Select Palette 2 (de-select palettes 0,1)
3 Enable Video Display
4 Select Graphics Mode 2 (de-select graphics mode 1)
5 Enable Blinking Chars (disable intensified backgrounds)
6
7
*/
if (LOG) logerror("VDU Mode Control %02x\n", data);
if ((get_display_mode(m_vdu_mode) != GRAPHICS_2) && (get_display_mode(data) == GRAPHICS_2))
{
m_vdu_plane = 0x0f;
m_vdu_border = 0;
}
if (get_display_mode(data) != GRAPHICS_2)
{
m_vdu_rdsel = 0;
}
if (get_display_mode(m_vdu_mode) != get_display_mode(data))
{
switch (get_display_mode(data))
{
case ALPHA_40:
case GRAPHICS_1:
m_vdu->set_hpixels_per_column(8);
m_vdu->set_clock(XTAL_28_63636MHz/32);
break;
case ALPHA_80:
m_vdu->set_hpixels_per_column(8);
m_vdu->set_clock(XTAL_28_63636MHz/16);
break;
case GRAPHICS_2:
m_vdu->set_hpixels_per_column(16);
m_vdu->set_clock(XTAL_28_63636MHz/32);
break;
}
}
m_vdu_mode = data;
break;
case 9: // VDU Colour Select
/*
bit description
0
1
2
3
4
5
6
7
*/
if (LOG) logerror("VDU Colour Select %02x\n", data);
m_vdu_color = data;
break;
case 0xb: // Clear Light Pen Latch
if (LOG) logerror("VDU Clear Light Pen Latch\n");
m_lpen = 0;
break;
case 0xc: // Set Light Pen Latch
if (LOG) logerror("VDU Set Light Pen Latch\n");
if (!m_lpen)
{
m_vdu->assert_light_pen_input();
}
m_lpen = 1;
break;
case 0xd: // VDU Colour Plane Write
/*
bit description
0 Allow CPU write to Blue Plane
1 Allow CPU write to Green Plane
2 Allow CPU write to Red Plane
3 Allow CPU write to Intensity Plane
4
5
6
7
*/
if (LOG) logerror("VDU Colour Plane Write %01x\n", data & 0x0f);
if (get_display_mode(m_vdu_mode) == GRAPHICS_2)
{
m_vdu_plane = data;
}
break;
case 0xe: // VDU Colour Plane Read
/*
bit description
0 Read Select bit 0 (RDSEL0)
1 Read Select bit 1 (RDSEL1)
2
3
4
5
6
7
*/
if (LOG) logerror("VDU Colour Plane Read %u\n", data & 0x03);
if (get_display_mode(m_vdu_mode) == GRAPHICS_2)
{
m_vdu_rdsel = data & 0x03;
}
break;
case 0xf: // VDU Graphics Mode 2 Border
/*
bit description
0 Border Blue
1 Border Green
2 Border Red
3 Border Intensity
4
5
6
7
*/
if (LOG) logerror("VDU Graphics Mode 2 Border %u\n", data & 0x0f);
m_vdu_border = data;
break;
}
}
//-------------------------------------------------
// mc6845_interface crtc_intf
//-------------------------------------------------
int pc1512_state::get_display_mode(UINT8 mode)
{
if (mode & MODE_GRAPHICS)
{
if (mode & MODE_GRAPHICS_2)
{
return GRAPHICS_2;
}
else
{
return GRAPHICS_1;
}
}
else
{
if (mode & MODE_ALPHA_80)
{
return ALPHA_80;
}
else
{
return ALPHA_40;
}
}
}
offs_t pc1512_state::get_char_rom_offset()
{
return ((m_lk->read() >> 5) & 0x03) << 11;
}
void pc1512_state::draw_alpha(bitmap_rgb32 &bitmap, const rectangle &cliprect, UINT16 ma, UINT8 ra, UINT16 y, UINT8 x_count, INT8 cursor_x, void *param)
{
offs_t char_rom_offset = get_char_rom_offset();
UINT32 *p = &bitmap.pix32(y + VFP_HIRES, HFP_HIRES);
if (get_display_mode(m_vdu_mode) == ALPHA_40)
p = &bitmap.pix32(y + VFP_LORES, HFP_LORES);
if (y > 199) return;
for (int column = 0; column < x_count; column++)
{
UINT8 code = m_video_ram[(ma + column) << 1];
UINT8 attr = m_video_ram[((ma + column) << 1) + 1];
int fg = attr & 0x0f;
int bg = attr >> 4;
if (m_vdu_mode & MODE_BLINK)
{
bg &= 0x07;
if (BIT(attr, 7) && !m_blink)
{
fg = bg;
}
}
offs_t addr = char_rom_offset | (code << 3) | (ra & 0x07);
UINT8 data = m_char_rom->base()[addr & 0x1fff];
if ((column == cursor_x) && m_cursor)
{
data = 0xff;
}
for (int bit = 0; bit < 8; bit++)
{
int color = BIT(data, 7) ? fg : bg;
*p = PALETTE[color]; p++;
data <<= 1;
}
}
}
int pc1512_state::get_color(UINT8 data)
{
if (data == 0) return m_vdu_color & 0x0f;
int color = PALETTE_0[data & 0x03];
if (m_vdu_color & COLOR_PALETTE_1)
{
color = PALETTE_1[data & 0x03];
}
else if (m_vdu_mode & MODE_PALETTE_2)
{
color = PALETTE_2[data & 0x03];
}
if (m_vdu_color & COLOR_INTENSITY)
{
color += 8;
}
return color;
};
void pc1512_state::draw_graphics_1(bitmap_rgb32 &bitmap, const rectangle &cliprect, UINT16 ma, UINT8 ra, UINT16 y, UINT8 x_count, INT8 cursor_x, void *param)
{
if (y > 199) return;
UINT32 *p = &bitmap.pix32(y + VFP_LORES, HFP_LORES);
for (int column = 0; column < x_count; column++)
{
offs_t offset = ((ra & 0x01) << 15) | ((ma + column) << 3);
UINT16 b = (m_video_ram[offset | 3] << 8) | m_video_ram[offset | 7];
for (int x = 0; x < 8; x++)
{
*p = PALETTE[get_color((BIT(b, 15) << 1) | BIT(b, 14))]; p++;
b <<= 2;
}
}
}
void pc1512_state::draw_graphics_2(bitmap_rgb32 &bitmap, const rectangle &cliprect, UINT16 ma, UINT8 ra, UINT16 y, UINT8 x_count, INT8 cursor_x, void *param)
{
if (y > 199) return;
UINT32 *p = &bitmap.pix32(y + VFP_HIRES, HFP_HIRES);
for (int column = 0; column < x_count; column++)
{
offs_t offset = ((ra & 0x01) << 15) | ((ma + column) << 3);
UINT16 i = BIT(m_vdu_color, 3) ? ((m_video_ram[offset | 0] << 8) | m_video_ram[offset | 4]) : 0;
UINT16 r = BIT(m_vdu_color, 2) ? ((m_video_ram[offset | 1] << 8) | m_video_ram[offset | 5]) : 0;
UINT16 g = BIT(m_vdu_color, 1) ? ((m_video_ram[offset | 2] << 8) | m_video_ram[offset | 6]) : 0;
UINT16 b = BIT(m_vdu_color, 0) ? ((m_video_ram[offset | 3] << 8) | m_video_ram[offset | 7]) : 0;
for (int x = 0; x < 16; x++)
{
*p = PALETTE[(BIT(i, 15) << 3) | (BIT(r, 15) << 2) | (BIT(g, 15) << 1) | BIT(b, 15)]; p++;
i <<= 1; r <<= 1; g <<= 1; b <<= 1;
}
}
}
static MC6845_UPDATE_ROW( pc1512_update_row )
{
pc1512_state *state = device->machine().driver_data<pc1512_state>();
switch (state->get_display_mode(state->m_vdu_mode))
{
case ALPHA_40:
case ALPHA_80:
state->draw_alpha(bitmap, cliprect, ma, ra, y, x_count, cursor_x, param);
break;
case GRAPHICS_1:
state->draw_graphics_1(bitmap, cliprect, ma, ra, y, x_count, cursor_x, param);
break;
case GRAPHICS_2:
state->draw_graphics_2(bitmap, cliprect, ma, ra, y, x_count, cursor_x, param);
break;
}
}
static MC6845_INTERFACE( crtc_intf )
{
false,
8,
NULL,
pc1512_update_row,
NULL,
DEVCB_NULL,
DEVCB_NULL,
DEVCB_NULL,
DEVCB_NULL,
NULL
};
void pc1512_state::video_start()
{
// allocate memory
m_video_ram.allocate(0x10000);
}
UINT32 pc1512_state::screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
{
if (m_vdu_mode & MODE_ENABLE_VIDEO)
{
m_blink_ctr++;
if (m_blink_ctr == 0x08)
{
m_cursor = !m_cursor;
}
else if (m_blink_ctr == 0x10)
{
m_cursor = !m_cursor;
m_blink = !m_blink;
m_blink_ctr = 0;
}
switch (get_display_mode(m_vdu_mode))
{
case ALPHA_40:
case GRAPHICS_1:
screen.set_visible_area(0, 359, 0, 245);
break;
case ALPHA_80:
case GRAPHICS_2:
screen.set_visible_area(0, 831, 0, 245);
break;
}
switch (get_display_mode(m_vdu_mode))
{
case ALPHA_40:
case ALPHA_80:
case GRAPHICS_1:
bitmap.fill(PALETTE[m_vdu_color & 0x0f], cliprect);
break;
case GRAPHICS_2:
bitmap.fill(PALETTE[m_vdu_border & 0x0f], cliprect);
break;
}
m_vdu->screen_update(screen, bitmap, cliprect);
}
else
{
bitmap.fill(RGB_BLACK, cliprect);
}
return 0;
}
//-------------------------------------------------
// MACHINE_CONFIG( pc1512 )
//-------------------------------------------------
MACHINE_CONFIG_FRAGMENT( pc1512_video )
MCFG_SCREEN_ADD(SCREEN_TAG, RASTER)
MCFG_SCREEN_UPDATE_DRIVER(pc1512_state, screen_update)
MCFG_SCREEN_SIZE(80*8, 24*8)
MCFG_SCREEN_VISIBLE_AREA(0, 80*8-1, 0, 24*8-1)
MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(2500))
MCFG_SCREEN_REFRESH_RATE(50)
MCFG_MC6845_ADD(AMS40041_TAG, AMS40041, SCREEN_TAG, XTAL_28_63636MHz/32, crtc_intf)
MACHINE_CONFIG_END