i86.c: 0x60 shadow omitted in previous patch. Needed for DOS 2. [Bavarese]

[MESS] vtvideo.c): finally fix smooth scrolling (ED084 = 1). See DIAG DISK -> VIDEO TEST -> screen 3 (Rainbow driver - SKIP 0).  [Bavarese]

[MESS] atari400.c - Slightly revised Atari XL cartridge loading so that it doesn't crash when loading 8K carts. Confirmed to fix MT#05108.  [alegend45]

Description fix from MASH for chihiro.c.  (nw)

src/emu/cpu/i86/i86.c

@@ -1143,7 +1143,7 @@ bool i8086_common_cpu_device::common_op(UINT8 op)
 //
 // 		Instructions are used in the boot sector for some versions of 
 //		MS-DOS  (e.g. the DEC Rainbow-100 version of DOS 2.x)
-//		case 0x60:
+		case 0x60:
 		case 0x70: // i_jo
 			JMP( OF);
 			break;

src/mame/drivers/chihiro.c

@@ -27,9 +27,9 @@ Games on this system include....
 | | 2004 | Wangan Midnight Maximum Tune (Japan)               | Namco                    | GDROM  | GDX-0008   | 317-5101-JPN |
 | | 2004 | Wangan Midnight Maximum Tune (Japan) (Rev A)       | Namco                    | GDROM  | GDX-0008A  | 317-5101-JPN |
 |*| 2004 | Wangan Midnight Maximum Tune (Japan) (Rev B)       | Namco                    | GDROM  | GDX-0008B  | 317-5101-JPN |
-| | 2004 | Wangan Midnight Maximum Tune (export)              | Namco                    | GDROM  | GDX-0009   | 317-5101-COM |
+| | 2004 | Wangan Midnight Maximum Tune (Export)              | Namco                    | GDROM  | GDX-0009   | 317-5101-COM |
-| | 2004 | Wangan Midnight Maximum Tune (export) (Rev A)      | Namco                    | GDROM  | GDX-0009A  | 317-5101-COM |
+| | 2004 | Wangan Midnight Maximum Tune (Export) (Rev A)      | Namco                    | GDROM  | GDX-0009A  | 317-5101-COM |
-|*| 2004 | Wangan Midnight Maximum Tune (export) (Rev B)      | Namco                    | GDROM  | GDX-0009B  | 317-5101-COM |
+|*| 2004 | Wangan Midnight Maximum Tune (Export) (Rev B)      | Namco                    | GDROM  | GDX-0009B  | 317-5101-COM |
 | | 2004 | Outrun 2 SP (Japan)                                | Sega                     | GDROM  | GDX-0011   |              |
 | | 2004 | Ghost Squad                                        | Sega                     | GDROM  | GDX-0012   | 317-0398-COM |
 |*| 2004 | Ghost Squad (Rev A)                                | Sega                     | GDROM  | GDX-0012A  | 317-0398-COM |
@@ -38,7 +38,7 @@ Games on this system include....
 |*| 2004 | Outrun 2 Special Tours (Rev A)                     | Sega                     | GDROM  | GDX-0014A  | 317-0xxx-COM |
 |*| 2005 | Wangan Midnight Maximum Tune 2 (Japan)             | Namco                    | GDROM  | GDX-0015   | 317-5106-JPN |
 |*| 2005 | Wangan Midnight Maximum Tune 2 (Japan) (Rev A)     | Namco                    | GDROM  | GDX-0015A  | 317-5106-JPN |
-|*| 2005 | Wangan Midnight Maximum Tune 2 (export)            | Namco                    | GDROM  | GDX-0016   | 317-5106-COM |
+|*| 2005 | Wangan Midnight Maximum Tune 2 (Export)            | Namco                    | GDROM  | GDX-0016   | 317-5106-COM |
 | | 2005 | Sega Network Taisen Mahjong MJ 3                   | Sega                     | GDROM  | GDX-0017   | 317-0414-JPN |
 | | 2005 | Sega Network Taisen Mahjong MJ 3 (Rev A)           | Sega                     | GDROM  | GDX-0017A  | 317-0414-JPN |
 | | 2005 | Sega Network Taisen Mahjong MJ 3 (Rev B)           | Sega                     | GDROM  | GDX-0017B  | 317-0414-JPN |
@@ -4883,9 +4883,9 @@ ROM_END
 // 0008     GAME( 2004, wangmdjo, wangmidj, chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (Japan) (GDX-0008)", GAME_NO_SOUND|GAME_NOT_WORKING )
 // 0008A    GAME( 2004, wangmdja, wangmidj, chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (Japan) (Rev A) (GDX-0008A)", GAME_NO_SOUND|GAME_NOT_WORKING )
 // 0008B    GAME( 2004, wangmidj, wangmidj, chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (Japan) (Rev B) (GDX-0008B)", GAME_NO_SOUND|GAME_NOT_WORKING )
-// 0009     GAME( 2004, wangmido, wangmid,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (export) (GDX-0009)", GAME_NO_SOUND|GAME_NOT_WORKING )
+// 0009     GAME( 2004, wangmido, wangmid,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (Export) (GDX-0009)", GAME_NO_SOUND|GAME_NOT_WORKING )
-// 0009A    GAME( 2004, wangmida, wangmid,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (export) (Rev A) (GDX-0009A)", GAME_NO_SOUND|GAME_NOT_WORKING )
+// 0009A    GAME( 2004, wangmida, wangmid,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (Export) (Rev A) (GDX-0009A)", GAME_NO_SOUND|GAME_NOT_WORKING )
-/* 0009B */ GAME( 2004, wangmid,  chihiro,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (export) (Rev B) (GDX-0009B)", GAME_NO_SOUND|GAME_NOT_WORKING )
+/* 0009B */ GAME( 2004, wangmid,  chihiro,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune (Export) (Rev B) (GDX-0009B)", GAME_NO_SOUND|GAME_NOT_WORKING )
 // 0011     GAME( 2004, outr2sp,  chihiro,  chihirogd,    chihiro, driver_device, 0, ROT0, "Sega",                     "Out Run 2 SP (Japan) (GDX-0011)", GAME_NO_SOUND|GAME_NOT_WORKING|GAME_SUPPORTS_SAVE )
 // 0012     GAME( 2004, ghostsqo, ghostsqu, chihirogd,    chihiro, driver_device, 0, ROT0, "Sega",                     "Ghost Squad (GDX-0012)", GAME_NO_SOUND|GAME_NOT_WORKING )
 /* 0012A */ GAME( 2004, ghostsqu, chihiro,  chihirogd,    chihiro, driver_device, 0, ROT0, "Sega",                     "Ghost Squad (Rev A) (GDX-0012A)", GAME_NO_SOUND|GAME_NOT_WORKING )
@@ -4894,7 +4894,7 @@ ROM_END
 /* 0014A */ GAME( 2004, outr2st,  chihiro,  chihirogd,    chihiro, driver_device, 0, ROT0, "Sega",                     "Out Run 2 Special Tours (Rev A) (GDX-0014A)", GAME_NO_SOUND|GAME_NOT_WORKING )
 // 0015     GAME( 2005, wanmd2bo, wangmd2b, chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune 2 (Japan) (GDX-0015)", GAME_NO_SOUND|GAME_NOT_WORKING )
 /* 0015A */ GAME( 2005, wangmd2b, chihiro,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune 2 (Japan) (Rev A) (GDX-0015A)", GAME_NO_SOUND|GAME_NOT_WORKING )
-/* 0016  */ GAME( 2005, wangmid2, chihiro,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune 2 (export) (GDX-0016)", GAME_NO_SOUND|GAME_NOT_WORKING )
+/* 0016  */ GAME( 2005, wangmid2, chihiro,  chihirogd,    chihiro, driver_device, 0, ROT0, "Namco",                    "Wangan Midnight Maximum Tune 2 (Export) (GDX-0016)", GAME_NO_SOUND|GAME_NOT_WORKING )
 // 0017     GAME( 2005, mj3o,     mj3,      chihirogd,    chihiro, driver_device, 0, ROT0, "Sega",                     "Sega Network Taisen Mahjong MJ 3 (GDX-0017)", GAME_NO_SOUND|GAME_NOT_WORKING )
 // 0017A    GAME( 2005, mj3a,     mj3,      chihirogd,    chihiro, driver_device, 0, ROT0, "Sega",                     "Sega Network Taisen Mahjong MJ 3 (Rev A) (GDX-0017A)", GAME_NO_SOUND|GAME_NOT_WORKING )
 // 0017B    GAME( 2005, mj3b,     mj3,      chihirogd,    chihiro, driver_device, 0, ROT0, "Sega",                     "Sega Network Taisen Mahjong MJ 3 (Rev B) (GDX-0017B)", GAME_NO_SOUND|GAME_NOT_WORKING )

src/mess/drivers/atari400.c

@@ -1745,10 +1745,10 @@ void a400_state::a800_setbank(int cart_mounted)
 				m_8000->set_base(m_region_lslot->base());
 				m_maincpu->space(AS_PROGRAM).unmap_write(0x8000, 0x9fff);
 
-				memcpy(m_region_maincpu->base() + 0x10000, m_region_lslot->base() + 0x2000, 0x2000);
+				memcpy(m_region_maincpu->base() + 0xa000, m_region_lslot->base() + 0x2000, 0x2000);
 			}
 			else if (m_a800_cart_type == A800_8K)
-				memcpy(m_region_maincpu->base() + 0x10000, m_region_lslot->base(), 0x2000);
+				memcpy(m_region_maincpu->base() + 0xa000, m_region_lslot->base(), 0x2000);
 			else
 				fatalerror("This type of cart is not supported yet in this driver. Please use a400 or a800.\n");
 		}

src/mess/drivers/rainbow.c

@@ -8,13 +8,17 @@
     ---------------------
     Driver is based entirely on the DEC-100 'B' variant (DEC-190 and DEC-100 A models are treated as clones).
     While this is OK for the compatible -190, it doesn't do justice to ancient '100 A' hardware.
+RBCONVERT.ZIP has details on how model 'A' differs from version B.
 
-    Currently, there are several issues here:
+Issues with this driver:
     (1) Keyboard emulation incomplete (inhibits the system from booting with ERROR 50).
-    (2) after fixing (1), IRQ logic for 100-B should be verified (text in RBCONVERT.ZIP has details concerning -A versus -B.
+
+(2) IRQ / DMA / arbitration logic should be verified 
 	DMA (needed for 'Extended communication option') or Z80-8088 arbitration is non-existent (E11/E13 dumps anyone?).
-	(3) Read errors when booting CP/M 2.x or DOS 2.x (secondary boot; read errors beyond T >= 2).
+
-	Seek (+ verify) and a number of signals (TRACK > 43 TG43, INDEX etc.) do not work (diag.disk aborts drive test). 
+(3) Read errors when booting CPM 2 / DOS 2.x / DOS 3 (secondary boot loader finds errors on tracks >= 2). 
+Seek (+ verify) and a number of signals (TRACK > 43 TG43, INDEX etc.) appear to be incorrect (-> diag.disk aborts drive test).
+UCSD systems (fort_sys, pas_sys) and diag disks boot!
 
     - NOT WORKING: serial (ERROR 60).
     - NOT WORKING: printer interface (ERROR 40). Like error 60 not mission-critical.
@@ -378,7 +382,7 @@ FLOPPY_FORMATS_MEMBER( rainbow_state::floppy_formats )
 FLOPPY_FORMATS_END
 
 static SLOT_INTERFACE_START( rainbow_floppies ) 
-	SLOT_INTERFACE( "525qd", FLOPPY_525_SSQD )   // "525ssdd"
+	SLOT_INTERFACE("525qd", FLOPPY_525_SSQD)  
 SLOT_INTERFACE_END
 
 
@@ -414,7 +418,8 @@ void rainbow_state::machine_start()
 	rom[0xf4000 + 0x363b]= 0xeb;  // COND => JMPS
 
     if (rom[0xf4174] == 0x75)
-    {   rom[0xf4174] = 0xeb; // jmps  RAINBOW100_LOGO__loc_33D
+	{
+		rom[0xf4174] = 0xeb; // jmps  RAINBOW100_LOGO__loc_33D
         rom[0xf4175] = 0x08;
     }
 
@@ -559,7 +564,7 @@ static INPUT_PORTS_START( rainbow100b_in )
 #endif
 		PORT_START("MONITOR TYPE")
 		PORT_DIPNAME( 0x03, 0x03, "MONOCHROME MONITOR")
-		PORT_DIPSETTING(    0x01, "PAPER WHITE" )
+PORT_DIPSETTING(0x01, "WHITE")
 		PORT_DIPSETTING(    0x02, "GREEN" )
 		PORT_DIPSETTING(    0x03, "AMBER" )
 
@@ -640,7 +645,8 @@ void rainbow_state::machine_reset()
 	/* configure RAM */
 	address_space &program = m_maincpu->space(AS_PROGRAM);
     if (m_inp8->read() < END_OF_RAM)
-	{	program.unmap_readwrite(m_inp8->read(), END_OF_RAM);
+	{
+		program.unmap_readwrite(m_inp8->read(), END_OF_RAM);
 	}
 
 	// BIOS can't handle soft resets (=> triggers ERROR 16).
@@ -695,9 +701,6 @@ void rainbow_state::machine_reset()
 
 UINT32 rainbow_state::screen_update_rainbow(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
 {
-	if (MOTOR_DISABLE_counter)
-		return 0;
-
 	m_crtc->palette_select( m_inp9->read() );
 
 	if ( m_SCREEN_BLANK )
@@ -1046,7 +1049,8 @@ WRITE8_MEMBER(rainbow_state::z80_diskcontrol_w)
 
 	floppy_connector *con = machine().device<floppy_connector>(names[drive]);
 	if (con)
-	{   m_floppy = con->get_device(); 
+	{
+		m_floppy = con->get_device();
 			if (m_floppy)
 			{  
 				selected_drive = drive; 
@@ -1073,7 +1077,8 @@ WRITE8_MEMBER(rainbow_state::z80_diskcontrol_w)
 				MOTOR_DISABLE_counter = 4800; // 2400 = 500 ms 
 
 //			m_fdc->set_force_ready(force_ready); 
-	} 	else
+	}
+	else
 	{
 //		    m_fdc->set_force_ready(false); 
 	} 
@@ -1090,8 +1095,10 @@ WRITE8_MEMBER(rainbow_state::z80_diskcontrol_w)
 		data = data & (255 -3);  
 		data = data | 8;  // MOTOR 0 OFF
 		data = data | 16; // MOTOR 1 OFF
-	}else
+	}
-	{	data = ( data & (255 -3) ) | m_unit;
+	else
+	{
+		data = (data & (255 - 3)) | m_unit;
 
  		if(m_unit < 2)
 			data = data & (255 - 8); // MOTOR 0 (for A or B)
@@ -1110,15 +1117,15 @@ READ8_MEMBER( rainbow_state::read_video_ram_r )
 INTERRUPT_GEN_MEMBER(rainbow_state::vblank_irq)
 {
 	raise_8088_irq(IRQ_8088_VBL);
+	m_crtc->notify_vblank(true);
 }
 
 WRITE_LINE_MEMBER( rainbow_state::clear_video_interrupt )
 {
 	lower_8088_irq(IRQ_8088_VBL);
+	m_crtc->notify_vblank(false);
 }
 
-
-
 READ8_MEMBER( rainbow_state::diagnostic_r ) // 8088 (port 0A READ). Fig.4-29 + table 4-15
 {
 //    printf("%02x DIP value ORed to diagnostic\n", ( m_inp1->read() | m_inp2->read() | m_inp3->read()   )  );
@@ -1346,7 +1353,7 @@ ROM_START( rainbow100a )
 	ROM_LOAD( "chargen.bin", 0x0000, 0x1000, CRC(1685e452) SHA1(bc299ff1cb74afcededf1a7beb9001188fdcf02f))
 ROM_END
 
-// ROM definition for 100-B (system module 70-1994-02, PSU H7842-D)
+// ROM definition for 100-B (system module 70-19974-02, PSU H7842-D)
 // Built until ~ May 1986 (see MP-01491-00)
 // - 32 K ROM (version 5.03)
 // - 128 K base and 896 K max. mem.

src/mess/video/vtvideo.c

@@ -10,18 +10,20 @@
     ----------------------------------
     - TESTS REQUIRED : do line and character attributes (plus combinations) match real hardware?
 
-    - JUMPY SOFT SCROLL : Soft scroll *should* be synced with beam or DMA (line linking/unlinking is done during VBI, in less than 550ms).
+- SCROLLING REGIONS / SPLIT SCREEN SCROLLING UNTESTED (if you open > 1 file with the VAX editor EDT)
-                          See 4.7.4 and up in VT manual.
+  See VT100 Technical Manual: 4.7.4 Address Shuffling to 4.7.9 Split Screen Smooth Scrolling.
+  More on scrolling regions: Rainbow 100 B technical documentation (QV069-GZ) April 1985 page 22
 
-    - UNDOCUMENTED FEATURES of DC011 / DC012 (CLUES WANTED)
+- INTERLACED MODE UNEMULATED:
-       A. (VT 100): DEC VT terminals are said to have a feature that doubles the number of lines
+  There is no RAM (on a Rainbow-100) to hold twice as many vertical lines, so the video chip 
-                    (50 real lines or just interlaced mode with 500 instead of 250 scanlines?)
+  doubles existing ones.           Flickers on CRTs and is of dubious value on modern hosts.
 
-       B. (DEC-100-B) fun PD program SQUEEZE.COM _compresses_ display to X/2 and Y/2
+- FUN WITH DC011 / DC012 REGISTERS (clues wanted):
-          - so picture takes a quarter of the original screen. How does it accomplish this?
+  Public domain program SQUEEZE.COM (for DEC-100-B) _compresses_ display to X/2 and Y/2
+  so picture takes a quarter of the original screen. How does it accomplish this?
 
     - IMPROVEMENTS:
-        - exact colors for different VR201 monitors ('paper white', green and amber)
+  exact colors for different VR201 monitors ('paper white', green and amber)
 
     Copyright MESS Team.
     Visit http://mamedev.org for licensing and usage restrictions.
@@ -116,7 +118,8 @@ void vt100_video_device::device_reset()
 	m_lba7 = 0;
 
 	m_scroll_latch = 0;
-	m_scroll_latch_valid = 0;
+	m_scroll_latch_valid = false;
+	m_last_scroll = 0;
 
 	m_blink_flip_flop = 0;
 	m_reverse_field = 0;
@@ -144,7 +147,8 @@ void rainbow_video_device::device_reset()
 	m_lba7 = 0;
 
 	m_scroll_latch = 0;
-	m_scroll_latch_valid = 0;
+	m_scroll_latch_valid = false;
+	m_last_scroll = 0;
 
 	m_blink_flip_flop = 0;
 	m_reverse_field = 0;
@@ -171,7 +175,8 @@ void vt100_video_device::recompute_parameters()
 
 	if (m_columns == 132) {
 		horiz_pix_total = m_columns * 9; // display 1 less filler pixel in 132 char. mode (DEC-100)
-	} else {
+	}
+	else {
 		horiz_pix_total = m_columns * 10; // normal 80 character mode.
 	}
 
@@ -210,24 +215,9 @@ WRITE8_MEMBER( vt100_video_device::dc012_w )
 
 	if (!(data & 0x08))
 	{
-		// The scroll offset put in 'm_scroll_latch' is a decimal offset controlling 10 scan lines.
-		// The BIOS first writes the least significant bits, then the 2 most significant bits.
-
-		// If scrolling up (incrementing the scroll latch), the additional line is linked in at the bottom.
-		// When the scroll latch is incremented back to 0, the top line of the scrolling region must be unlinked.
-
-		// When scrolling down (decrementing the scroll latch), new lines must be linked in at the top of the scroll region
-		// and unlinked down at the bottom.
-
-		// Note that the scroll latch value will be used during the next frame rather than the current frame.
-		// All line linking/unlinking is done during the vertical blanking interval (< 550ms).
-
-		// More on scrolling regions: Rainbow 100 B technical documentation (QV069-GZ) April 1985 page 22
-		// Also see VT100 Technical Manual: 4.7.4 Address Shuffling to 4.7.9 Split Screen Smooth Scrolling.
 		if (!(data & 0x04))
 		{
-			m_scroll_latch_valid = 0; // LSB is written first.
+			m_scroll_latch_valid = false; // LSB is written first.
-
 			// set lower part scroll
 			m_scroll_latch = data & 0x03;
 		}
@@ -235,8 +225,7 @@ WRITE8_MEMBER( vt100_video_device::dc012_w )
 		{
 			// set higher part scroll
 			m_scroll_latch = (m_scroll_latch & 0x03) | ((data & 0x03) << 2);
-
+			m_scroll_latch_valid = true;
-			m_scroll_latch_valid = 1; // MSB is written last.
 		}
 	}
 	else
@@ -492,9 +481,11 @@ void rainbow_video_device::display_char(bitmap_ind16 &bitmap, UINT8 code, int x,
 	UINT16 y_preset;
 	UINT16 x_preset, d_x_preset;
 	if (m_columns == 132)
-	{     x_preset   = x * 9;
+	{
+		x_preset = x * 9;
 			d_x_preset = x * 18;
-	} else
+	}
+	else
 	{
 			x_preset   = x * 10;
 			d_x_preset = x * 20;
@@ -513,8 +504,6 @@ void rainbow_video_device::display_char(bitmap_ind16 &bitmap, UINT8 code, int x,
 
 	display_type = display_type & 3;
 
-	static int old_scroll_region;
-
 	// * SCREEN ATTRIBUTES (see VT-180 manual 6-30) *
 	// 'reverse field' = reverse video over entire screen
 
@@ -546,42 +535,25 @@ void rainbow_video_device::display_char(bitmap_ind16 &bitmap, UINT8 code, int x,
 	bool double_width  = (display_type != 3) ? true  : false; // all except normal: double width
 	bool double_height = (display_type &  1) ? false : true;  // 0,2 = double height
 
+	int smooth_offset = 0;
+	if (scroll_region != 0)
+		smooth_offset = m_last_scroll; // valid after VBI
+
+	int extra_scan_line = 0;
 	for (int scan_line = 0; scan_line < 10; scan_line++)
 	{
 		y_preset = y * 10 + scan_line;
 
-		// Offset to bitmap in char-rom (used later below)
+		int i = scan_line + smooth_offset; // offset to bitmap in char-rom (+ scroll)
-		int i = scan_line;
+		if (i > 9) // SMOOTH SCROLL - fill previous scan line:
+		{
+			extra_scan_line += 1;
+			i = smooth_offset - extra_scan_line; // correct bitmap
 
-		// Affects 'i'  / 'y_preset' / 'scan_line' (= LOOP VARIABLE)
+			y_preset -= scan_line; 
-		if ( m_scroll_latch_valid == 1)
+			if (y > 0)
-		{
+				y_preset -= extra_scan_line;  // Y * 10  - extra_scan_line
-			// **** START IF SCROLL REGION:
-			if ( (old_scroll_region == 0) && (scroll_region == 1) )
-			{
-			if (scan_line == 0)  // * EXECUTED ONCE *
-			{
-				scan_line = m_scroll_latch; // write less lines  ! SIDE EFFECT ON LOOP !
-				i = m_scroll_latch;         // set hard offset to char-rom
 			}
-			}
-
-			// **** MIDDLE OF REGION:
-			if ( (old_scroll_region == 1) && (scroll_region == 1) )
-			{
-			if (    ( y * 10 + scan_line - m_scroll_latch ) >=   0 )
-						y_preset = y * 10 + scan_line - m_scroll_latch;
-			}
-
-			// **** END OF SCROLL REGION:
-			if ( (old_scroll_region == 1) && (scroll_region == 0) )
-			{
-			if (i > (9 - m_scroll_latch) )
-			{   old_scroll_region = m_scroll_latch_valid; // keep track
-				return;                         // WHAT HAPPENS WITH THE REST OF THE LINE (BLANK ?)
-			}
-			}
-		} // (IF) scroll latch valid
 
 		switch (display_type)
 		{
@@ -613,7 +585,8 @@ void rainbow_video_device::display_char(bitmap_ind16 &bitmap, UINT8 code, int x,
 					if (invert == 0)
 						line = 0xff; // CASE 5 A)
 					else
-					{    line = 0x00; // CASE 5 B)
+				{
+					line = 0x00; // CASE 5 B)
 						back_intensity = 0; // OVERRIDE: BLACK BACKGROUND
 					}
 			}
@@ -622,7 +595,8 @@ void rainbow_video_device::display_char(bitmap_ind16 &bitmap, UINT8 code, int x,
 		for (int b = 0; b < 8; b++) // 0..7
 		{
 			if (blank)
-			{       bit = m_reverse_field ^ m_basic_attribute;
+			{
+				bit = m_reverse_field ^ m_basic_attribute;
 			}
 			else
 			{
@@ -652,7 +626,6 @@ void rainbow_video_device::display_char(bitmap_ind16 &bitmap, UINT8 code, int x,
 			}
 		} // for (8 bit)
 
-
 		// char interleave (X) is filled with last bit
 		if (double_width)
 		{
@@ -661,7 +634,8 @@ void rainbow_video_device::display_char(bitmap_ind16 &bitmap, UINT8 code, int x,
 			bitmap.pix16(y_preset, d_x_preset + 17) = bit;
 
 			if (m_columns == 80)
-			{   bitmap.pix16(y_preset, d_x_preset + 18) = bit;
+			{
+				bitmap.pix16(y_preset, d_x_preset + 18) = bit;
 				bitmap.pix16(y_preset, d_x_preset + 19) = bit;
 			}
 		}
@@ -672,7 +646,6 @@ void rainbow_video_device::display_char(bitmap_ind16 &bitmap, UINT8 code, int x,
 			if (m_columns == 80)
 				bitmap.pix16(y_preset, x_preset + 9) = bit;
 		}
-
 	} // for (scan_line)
 
 }
@@ -765,6 +738,20 @@ void rainbow_video_device::video_update(bitmap_ind16 &bitmap, const rectangle &c
 
 }
 
+void rainbow_video_device::notify_vblank(bool v)
+{
+	static bool v_last;
+	m_notify_vblank = v;
+
+	if (m_scroll_latch_valid)
+	{
+		// Line linking / unlinking is done during VBI (see 4.7.4 and up in VT manual).
+		if ((v == false) && (v_last == true))
+			m_last_scroll = m_scroll_latch;
+	}
+
+	v_last = v;
+}
 
 void rainbow_video_device::palette_select ( int choice )
 {
@@ -778,9 +765,9 @@ void rainbow_video_device::palette_select ( int choice )
 						break;
 
 			case 0x02:
-						m_palette->set_pen_color(1, 0 , 205 -50, 70 - 50);        // GREEN (dim)
+		m_palette->set_pen_color(1, 35, 200 - 55, 75);        // GREEN (dim)
-						m_palette->set_pen_color(2, 0 , 205,     70     );        // GREEN (NORMAL)
+		m_palette->set_pen_color(2, 35 + 55, 200, 75 + 55);        // GREEN (NORMAL)
-						m_palette->set_pen_color(3, 0,  205 +50, 70 + 50);        // GREEN (brighter)
+		m_palette->set_pen_color(3, 35 + 110, 200 + 55, 75 + 110);         // GREEN (brighter)
 						break;
 
 			case 0x03:

src/mess/video/vtvideo.h

@@ -57,7 +57,7 @@ protected:
 
 	// dc012 attributes
 	UINT8 m_scroll_latch;
-	UINT8 m_scroll_latch_valid;
+	bool m_scroll_latch_valid;
 	UINT8 m_blink_flip_flop;
 	UINT8 m_reverse_field;
 	UINT8 m_basic_attribute;
@@ -71,6 +71,9 @@ protected:
 
 	const char *m_char_rom_tag; /* character rom region */
 	required_device<palette_device> m_palette;
+	
+	bool m_notify_vblank;
+	int m_last_scroll;
 };
 
 
@@ -84,6 +87,7 @@ public:
 
 	int MHFU(int);
 	void palette_select(int choice);
+	void notify_vblank(bool choice);
 protected:
 	virtual void display_char(bitmap_ind16 &bitmap, UINT8 code, int x, int y, UINT8 scroll_region, UINT8 display_type);
 	virtual void device_reset();