diff --git a/scripts/target/mame/mess.lua b/scripts/target/mame/mess.lua
index 925a4fe9272..93b845d4329 100644
--- a/scripts/target/mame/mess.lua
+++ b/scripts/target/mame/mess.lua
@@ -2113,6 +2113,7 @@ files {
 
 createMESSProjects(_target, _subtarget, "sharp")
 files {             
+	MAME_DIR .. "src/mess/drivers/hh_sm510.c",
 	MAME_DIR .. "src/mess/video/mz700.c",       
 	MAME_DIR .. "src/mess/drivers/mz700.c",     
 	MAME_DIR .. "src/mess/drivers/pc1500.c",    
diff --git a/src/emu/cpu/sm510/sm510.c b/src/emu/cpu/sm510/sm510.c
index af0f5423101..5a5c364376d 100644
--- a/src/emu/cpu/sm510/sm510.c
+++ b/src/emu/cpu/sm510/sm510.c
@@ -21,7 +21,10 @@ const device_type SM510 = &device_creator<sm510_device>;
 
 // internal memory maps
 static ADDRESS_MAP_START(program_2_7k, AS_PROGRAM, 8, sm510_base_device)
-	AM_RANGE(0x0000, 0x0aff) AM_ROM
+	AM_RANGE(0x0000, 0x02af) AM_ROM
+	AM_RANGE(0x0400, 0x06af) AM_ROM
+	AM_RANGE(0x0800, 0x0aaf) AM_ROM
+	AM_RANGE(0x0c00, 0x0eaf) AM_ROM
 ADDRESS_MAP_END
 
 
@@ -87,20 +90,22 @@ void sm510_base_device::device_start()
 
 	// zerofill
 	memset(m_stack, 0, sizeof(m_stack));
-	m_op = 0;
-	m_prev_op = 0;
 	m_pc = 0;
 	m_prev_pc = 0;
+	m_op = 0;
+	m_prev_op = 0;
+	m_param = 0;
 	m_acc = 0;
 	m_bl = 0;
 	m_bm = 0;
 
 	// register for savestates
 	save_item(NAME(m_stack));
-	save_item(NAME(m_op));
-	save_item(NAME(m_prev_op));
 	save_item(NAME(m_pc));
 	save_item(NAME(m_prev_pc));
+	save_item(NAME(m_op));
+	save_item(NAME(m_prev_op));
+	save_item(NAME(m_param));
 	save_item(NAME(m_acc));
 	save_item(NAME(m_bl));
 	save_item(NAME(m_bm));
diff --git a/src/emu/cpu/sm510/sm510.h b/src/emu/cpu/sm510/sm510.h
index ec20ee4272c..34042b093c4 100644
--- a/src/emu/cpu/sm510/sm510.h
+++ b/src/emu/cpu/sm510/sm510.h
@@ -67,10 +67,10 @@ protected:
 	int m_prgmask;
 	int m_datamask;
 
-	UINT16 m_prev_pc;
 	UINT16 m_pc;
-	UINT8 m_prev_op;
+	UINT16 m_prev_pc;
 	UINT8 m_op;
+	UINT8 m_prev_op;
 	UINT8 m_param;
 	int m_stack_levels;
 	UINT16 m_stack[2];
diff --git a/src/mame/mess.lst b/src/mame/mess.lst
index f8f15b810da..dba48281b60 100644
--- a/src/mame/mess.lst
+++ b/src/mame/mess.lst
@@ -2187,6 +2187,9 @@ cfrogger    // Coleco
 // hh_pic16
 maniac      // Ideal
 
+// hh_sm510
+ktopgun     // Konami
+
 // hh_tms1k
 mathmagi    // APF
 amaztron    // Coleco
diff --git a/src/mess/drivers/hh_sm510.c b/src/mess/drivers/hh_sm510.c
new file mode 100644
index 00000000000..7b84f673336
--- /dev/null
+++ b/src/mess/drivers/hh_sm510.c
@@ -0,0 +1,147 @@
+// license:BSD-3-Clause
+// copyright-holders:hap, Sean Riddle
+/***************************************************************************
+
+  Sharp SM510 MCU x..
+
+  TODO:
+  - barnacles
+
+***************************************************************************/
+
+#include "emu.h"
+#include "cpu/sm510/sm510.h"
+#include "sound/speaker.h"
+
+// internal artwork
+//..
+
+
+class hh_sm510_state : public driver_device
+{
+public:
+	hh_sm510_state(const machine_config &mconfig, device_type type, const char *tag)
+		: driver_device(mconfig, type, tag),
+		m_maincpu(*this, "maincpu"),
+		m_inp_matrix(*this, "IN"),
+		m_speaker(*this, "speaker")
+	{ }
+
+	// devices
+	required_device<cpu_device> m_maincpu;
+	optional_ioport_array<5> m_inp_matrix; // max 5
+	optional_device<speaker_sound_device> m_speaker;
+
+	// misc common
+	UINT16 m_inp_mux;                   // multiplexed inputs mask
+
+	UINT8 read_inputs(int columns);
+
+	// display common
+	//..
+
+protected:
+	virtual void machine_start();
+	virtual void machine_reset();
+};
+
+
+// machine start/reset
+
+void hh_sm510_state::machine_start()
+{
+	// zerofill
+	m_inp_mux = 0;
+
+	// register for savestates
+	save_item(NAME(m_inp_mux));
+}
+
+void hh_sm510_state::machine_reset()
+{
+}
+
+
+
+/***************************************************************************
+
+  Helper Functions
+
+***************************************************************************/
+
+UINT8 hh_sm510_state::read_inputs(int columns)
+{
+	return 0;
+}
+
+
+
+/***************************************************************************
+
+  Minidrivers (subclass, I/O, Inputs, Machine Config)
+
+***************************************************************************/
+
+/***************************************************************************
+
+  Konami Top Gun
+  * x
+
+***************************************************************************/
+
+class ktopgun_state : public hh_sm510_state
+{
+public:
+	ktopgun_state(const machine_config &mconfig, device_type type, const char *tag)
+		: hh_sm510_state(mconfig, type, tag)
+	{ }
+};
+
+// handlers
+
+//..
+
+
+// config
+
+static INPUT_PORTS_START( ktopgun )
+INPUT_PORTS_END
+
+static MACHINE_CONFIG_START( ktopgun, ktopgun_state )
+
+	/* basic machine hardware */
+	MCFG_CPU_ADD("maincpu", SM510, 10000)
+
+	/* no video! */
+
+	/* sound hardware */
+	MCFG_SPEAKER_STANDARD_MONO("mono")
+	MCFG_SOUND_ADD("speaker", SPEAKER_SOUND, 0)
+	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 0.25)
+MACHINE_CONFIG_END
+
+
+
+
+
+
+
+
+/***************************************************************************
+
+  Game driver(s)
+
+***************************************************************************/
+
+ROM_START( ktopgun )
+	ROM_REGION( 0x1000, "maincpu", 0 )
+	ROM_LOAD( "topgun_die.bin", 0x0000, 0x1000, CRC(50870b35) SHA1(cda1260c2e1c180995eced04b7d7ff51616dcef5) )
+ROM_END
+
+
+
+
+
+
+/*    YEAR  NAME       PARENT COMPAT MACHINE   INPUT      INIT              COMPANY, FULLNAME, FLAGS */
+CONS( 1990, ktopgun,   0,        0, ktopgun,   ktopgun,   driver_device, 0, "Konami", "Top Gun (Konami)", GAME_SUPPORTS_SAVE | GAME_NOT_WORKING )