From e5268aa7216bdb86c4b62c4e3975b48f41c158ad Mon Sep 17 00:00:00 2001
From: arbee <rb6502@users.noreply.github.com>
Date: Wed, 12 Sep 2018 23:50:19 -0400
Subject: [PATCH] cgthree: allow system to program palette (nw)

---
 src/devices/bus/sbus/cgthree.cpp | 26 ++++++++++++++++++++++++--
 src/devices/bus/sbus/cgthree.h   |  1 +
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/devices/bus/sbus/cgthree.cpp b/src/devices/bus/sbus/cgthree.cpp
index 5ce50cbd9a4..2dc0dbe5b6c 100644
--- a/src/devices/bus/sbus/cgthree.cpp
+++ b/src/devices/bus/sbus/cgthree.cpp
@@ -55,6 +55,7 @@ void sbus_cgthree_device::device_start()
 {
 	m_vram = std::make_unique<uint32_t[]>(0x100000/4);
 	m_vram2 = std::make_unique<uint32_t[]>(0x100000/4);
+	entry = r = g = b = step = 0;
 }
 
 void sbus_cgthree_device::install_device()
@@ -98,7 +99,28 @@ READ32_MEMBER(sbus_cgthree_device::unknown_r)
 
 WRITE32_MEMBER(sbus_cgthree_device::unknown_w)
 {
-	logerror("%s: unknown_w: %08x = %08x & %08x\n", machine().describe_context(), offset << 2, data, mem_mask);
+	if (offset == 0x100000)
+	{
+		entry = data >> 24;
+		step = 0;
+	}
+	else if (offset == 0x100001)
+	{
+		switch (step)
+		{
+			case 0: r = data>>24; step++; break;
+			case 1: g = data>>24; step++; break;
+			case 2:
+				b = data>>24;
+				m_palette->set_pen_color(entry, rgb_t(r, g, b));
+				step = 0;
+				break;
+		}
+	}
+	else
+	{
+		logerror("%s: unknown_w: %08x = %08x & %08x\n", machine().describe_context(), offset << 2, data, mem_mask);
+	}
 }
 
 READ8_MEMBER(sbus_cgthree_device::regs_r)
@@ -135,4 +157,4 @@ READ32_MEMBER(sbus_cgthree_device::vram2_r)
 WRITE32_MEMBER(sbus_cgthree_device::vram2_w)
 {
 	COMBINE_DATA(&m_vram2[offset]);
-}
\ No newline at end of file
+}
diff --git a/src/devices/bus/sbus/cgthree.h b/src/devices/bus/sbus/cgthree.h
index 25fb48bb711..32b4eee6e8c 100644
--- a/src/devices/bus/sbus/cgthree.h
+++ b/src/devices/bus/sbus/cgthree.h
@@ -51,6 +51,7 @@ private:
 	std::unique_ptr<uint32_t[]> m_vram2; // ???
 	required_device<screen_device> m_screen;
 	required_device<palette_device> m_palette;
+	int entry, r, g, b, step;
 };
 
 // device type definition