Confirmed that video register [1] controls upper color bank (fixes Mazer Blazer CRT test). Upcoming: device-ify custom VCU

.gitattributes

@@ -2476,6 +2476,8 @@ src/emu/video/m50458.c svneol=native#text/plain
 src/emu/video/m50458.h svneol=native#text/plain
 src/emu/video/mb90082.c svneol=native#text/plain
 src/emu/video/mb90082.h svneol=native#text/plain
+src/emu/video/mb_vcu.c svneol=native#text/plain
+src/emu/video/mb_vcu.h svneol=native#text/plain
 src/emu/video/mc6845.c svneol=native#text/plain
 src/emu/video/mc6845.h svneol=native#text/plain
 src/emu/video/mc6847.c svneol=native#text/plain

src/emu/video/mb_vcu.c

@@ -0,0 +1,115 @@
+// license: ?
+// copyright-holders: Angelo Salese
+/***************************************************************************
+
+Device for Mazer Blazer/Great Guns custom Video Controller Unit
+
+***************************************************************************/
+
+#include "emu.h"
+#include "video/mb_vcu.h"
+
+
+
+//**************************************************************************
+//  GLOBAL VARIABLES
+//**************************************************************************
+
+// device type definition
+const device_type MB_VCU = &device_creator<mb_vcu_device>;
+
+
+//**************************************************************************
+//  LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+//  mb_vcu_device - constructor
+//-------------------------------------------------
+
+mb_vcu_device::mb_vcu_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+	: device_t(mconfig, MB_VCU, "Mazer Blazer custom VCU", tag, owner, clock, "mb_vcu", __FILE__),
+	  device_video_interface(mconfig, *this)
+{
+}
+
+//-------------------------------------------------
+//  device_config_complete - perform any
+//  operations now that the configuration is
+//  complete
+//-------------------------------------------------
+
+void mb_vcu_device::device_config_complete()
+{
+	// inherit a copy of the static data
+	const mb_vcu_interface *intf = reinterpret_cast<const mb_vcu_interface *>(static_config());
+	if (intf != NULL)
+	{
+		*static_cast<mb_vcu_interface *>(this) = *intf;
+	}
+
+	// or initialize to defaults if none provided
+	else
+	{
+		m_cpu_tag = NULL;
+	}
+}
+
+//-------------------------------------------------
+//  device_validity_check - perform validity checks
+//  on this device
+//-------------------------------------------------
+
+void mb_vcu_device::device_validity_check(validity_checker &valid) const
+{
+}
+
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void mb_vcu_device::device_start()
+{
+	if(m_cpu_tag)
+	{
+		m_cpu = machine().device(m_cpu_tag);
+	}
+	else
+	{
+		m_cpu = NULL;
+	}
+
+}
+
+
+//-------------------------------------------------
+//  device_reset - device-specific reset
+//-------------------------------------------------
+
+void mb_vcu_device::device_reset()
+{
+}
+
+
+//**************************************************************************
+//  READ/WRITE HANDLERS
+//**************************************************************************
+
+READ8_MEMBER( mb_vcu_device::read )
+{
+	return 0;
+}
+
+WRITE8_MEMBER( mb_vcu_device::write )
+{
+}
+
+//-------------------------------------------------
+//  update_screen -
+//-------------------------------------------------
+
+UINT32 mb_vcu_device::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
+{
+	return 0;
+}

src/emu/video/mb_vcu.h

@@ -0,0 +1,74 @@
+// license: ?
+// copyright-holders: Angelo Salese
+/***************************************************************************
+
+Template for skeleton device
+
+***************************************************************************/
+
+#pragma once
+
+#ifndef __MB_VCUDEV_H__
+#define __MB_VCUDEV_H__
+
+
+
+//**************************************************************************
+//  INTERFACE CONFIGURATION MACROS
+//**************************************************************************
+
+#define MCFG_MB_VCU_ADD(_tag,_freq,_config) \
+	MCFG_DEVICE_ADD(_tag, MB_VCU, _freq) \
+	MCFG_DEVICE_CONFIG(_config)
+
+//**************************************************************************
+//  TYPE DEFINITIONS
+//**************************************************************************
+
+// ======================> mb_vcu_interface
+
+struct mb_vcu_interface
+{
+	const char         *m_cpu_tag;
+};
+
+// ======================> mb_vcu_device
+
+class mb_vcu_device : public device_t,
+					  public device_video_interface,
+					  public mb_vcu_interface
+{
+public:
+	// construction/destruction
+	mb_vcu_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
+
+	// I/O operations
+	DECLARE_WRITE8_MEMBER( write );
+	DECLARE_READ8_MEMBER( read );
+
+	UINT32 screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect);
+
+protected:
+	// device-level overrides
+	virtual void device_config_complete();
+	virtual void device_validity_check(validity_checker &valid) const;
+	virtual void device_start();
+	virtual void device_reset();
+private:
+
+	device_t *m_cpu;
+};
+
+
+// device type definition
+extern const device_type MB_VCU;
+
+
+
+//**************************************************************************
+//  GLOBAL VARIABLES
+//**************************************************************************
+
+
+
+#endif

src/emu/video/video.mak

@@ -268,6 +268,15 @@ ifneq ($(filter MB90082,$(VIDEOS)),)
 VIDEOOBJS+= $(VIDEOOBJ)/mb90082.o
 endif
 
+#-------------------------------------------------
+#
+#@src/emu/video/mb_vcu.h,VIDEOS += MB_VCU
+#-------------------------------------------------
+
+ifneq ($(filter MB_VCU,$(VIDEOS)),)
+VIDEOOBJS+= $(VIDEOOBJ)/mb_vcu.o
+endif
+
 #-------------------------------------------------
 #
 #@src/emu/video/mc6845.h,VIDEOS += MC6845

src/mame/drivers/mazerbla.c

@@ -109,6 +109,9 @@ master z80
 [0x0021]: clears i/o at 0x6a (lamps), clears 0xe563, 0xe004, 0xe000, 0xe001, 0xe007, 0xe002, 0xe003, 0xe005,
           0xc04f, 0xe572, enables IM 2, clears 0xe581 / 0xe583 (word), puts default initials (0x2274->0xe058)
 
+video z80
+[0x535]:
+[0x03c]: start of proper code
 
 ****************************************************************************/
 
@@ -491,7 +494,7 @@ READ8_MEMBER(mazerbla_state::vcu_set_cmd_param_r)
 
 	m_plane = m_mode & 3;
 
-	return 0;
+	return machine().rand();
 }
 
 
@@ -503,11 +506,7 @@ READ8_MEMBER(mazerbla_state::vcu_set_gfx_addr_r)
 	int bits = 0;
 	UINT8 color_base = 0;
 
-	if (m_game_id == MAZERBLA)
-		color_base = 0x80;  /* 0x80 - good for Mazer Blazer: (only in game, CRT test mode is bad) */
-
-	if (m_game_id == GREATGUN)
-		color_base = 0x00;  /* 0x00 - good for Great Guns: (both in game and CRT test mode) */
+	color_base = m_vcu_video_reg[1] << 4;
 
 //    if ((mode <= 0x07) || (mode >= 0x10))
 /*
@@ -660,7 +659,7 @@ READ8_MEMBER(mazerbla_state::vcu_set_gfx_addr_r)
 		break;
 	}
 
-	return 0;
+	return machine().rand();
 }
 
 READ8_MEMBER(mazerbla_state::vcu_set_clr_addr_r)
@@ -853,7 +852,7 @@ READ8_MEMBER(mazerbla_state::vcu_set_clr_addr_r)
 		break;
 	}
 
-	return 0;
+	return machine().rand();
 }
 
 /*************************************

src/mame/mame.mak

@@ -298,6 +298,7 @@ VIDEOS += I8275
 VIDEOS += K053250
 VIDEOS += M50458
 VIDEOS += MB90082
+VIDEOS += MB_VCU
 VIDEOS += MC6845
 #VIDEOS += MC6847
 #VIDEOS += MSM6255