From 4eaaf63226666d304f067d3dd2468a54f0ed5c70 Mon Sep 17 00:00:00 2001
From: David Haywood <davidhaywood@users.noreply.github.com>
Date: Wed, 24 May 2017 00:16:14 +0100
Subject: [PATCH] make cybar120 look more reasonable

---
 src/devices/video/ppu2c0x.cpp |  6 ++++++
 src/mame/drivers/nes_vt.cpp   | 40 +++++++++++++++++++++++++++++++++--
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/devices/video/ppu2c0x.cpp b/src/devices/video/ppu2c0x.cpp
index de600b32326..2d35073825a 100644
--- a/src/devices/video/ppu2c0x.cpp
+++ b/src/devices/video/ppu2c0x.cpp
@@ -761,6 +761,11 @@ void ppu2c0x_device::draw_sprite_pixel(int sprite_xpos, int color, int pixel, ui
 	bitmap.pix16(m_scanline, sprite_xpos + pixel) = paldata[pixel_data];
 }
 
+void ppu2c0x_device::read_extra_sprite_bits(int sprite_index)
+{
+	// needed for some clones
+}
+
 void ppu2c0x_device::draw_sprites( uint8_t *line_priority )
 {
 	bitmap_ind16 &bitmap = *m_bitmap;
@@ -811,6 +816,7 @@ void ppu2c0x_device::draw_sprites( uint8_t *line_priority )
 		pri   =  m_spriteram[sprite_index + 2] & 0x20;
 		flipx =  m_spriteram[sprite_index + 2] & 0x40;
 		flipy =  m_spriteram[sprite_index + 2] & 0x80;
+		read_extra_sprite_bits(sprite_index);
 
 		if (size == 16)
 		{
diff --git a/src/mame/drivers/nes_vt.cpp b/src/mame/drivers/nes_vt.cpp
index 0a82b35f943..4b54af99de5 100644
--- a/src/mame/drivers/nes_vt.cpp
+++ b/src/mame/drivers/nes_vt.cpp
@@ -365,6 +365,9 @@ void nes_vt_state::machine_reset()
 
 int nes_vt_state::calculate_real_video_address(int addr, int extended, int readtype)
 {
+	// might be a VT09 only feature (8bpp or 4bpp direct colour mode??)
+	int alt_order = m_ppu->get_201x_reg(0x0) & 0x40;
+
 	if (readtype == 0)
 	{
 		if (m_ppu->get_201x_reg(0x0) & 0x10)
@@ -505,7 +508,16 @@ int nes_vt_state::calculate_real_video_address(int addr, int extended, int readt
 		finaladdr = ((m_410x[0x0] & 0x0F) << 21) | (va20_va18 << 18) | (va17_va10 << 10) | (addr & 0x03ff);
 		
 		if (is4bpp)
-			finaladdr = ((finaladdr &~0xf) << 1) | (va34 << 4) | (finaladdr & 0xf);	
+		{
+			if (!alt_order)
+			{
+				finaladdr = ((finaladdr &~0xf) << 1) | (va34 << 4) | (finaladdr & 0xf);
+			}
+			else
+			{
+				finaladdr = (finaladdr << 1) | (va34 << 4);
+			}
+		}
 	}
 	else
 	{
@@ -544,7 +556,17 @@ int nes_vt_state::calculate_real_video_address(int addr, int extended, int readt
 		finaladdr = ((m_410x[0x0] & 0x0f) << 21) | (va17_va10 << 13) | (eva2_eva0 << 10) | (addr & 0x03ff);
 
 		if (is4bpp)
-			finaladdr = ((finaladdr &~0xf) << 1) | (va34 << 4) | (finaladdr & 0xf);
+		{
+			if (!alt_order)
+			{
+				finaladdr = ((finaladdr &~0xf) << 1) | (va34 << 4) | (finaladdr & 0xf);
+			}
+			else
+			{
+				finaladdr = (finaladdr << 1) | (va34 << 4);
+			}
+
+		}
 	}
 
 	return finaladdr;
@@ -741,8 +763,22 @@ static const gfx_layout helper_layout =
 	4*64
 };
 
+static const gfx_layout helper2_layout =
+{
+	8,8,
+	RGN_FRAC(1,1),
+	4,
+	{ 0*8, 1*8, 2*8, 3*8 },
+	{ 0,1,2,3,4,5,6,7 },
+	{ 0*16, 1*16, 2*16, 3*16,4*16,5*16,5*16,6*16,7*16 },
+	4*64
+};
+
+
+
 static GFXDECODE_START( vt03_helper )
 	GFXDECODE_ENTRY( "mainrom", 0, helper_layout,  0x0, 2  )
+	GFXDECODE_ENTRY( "mainrom", 0, helper2_layout,  0x0, 2  )
 GFXDECODE_END