diff --git a/src/emu/cpu/amis2000/amis2000.c b/src/emu/cpu/amis2000/amis2000.c
index 5afe974f681..d6c4967d0dc 100644
--- a/src/emu/cpu/amis2000/amis2000.c
+++ b/src/emu/cpu/amis2000/amis2000.c
@@ -5,6 +5,7 @@
   American Microsystems, Inc.(AMI) S2000-family 4-bit MCU cores, introduced late 1970s
   
   TODO:
+  - bug(s)? - MESS wildfire.c doesn't work yet
   - unemulated opcodes (need more testing material)
   - support external program map
   - add 50/60hz timer
@@ -25,12 +26,12 @@ const device_type AMI_S2150 = &device_creator<amis2150_device>;
 
 // internal memory maps
 static ADDRESS_MAP_START(program_1k, AS_PROGRAM, 8, amis2000_device)
-	AM_RANGE(0x0000, 0x03ff) AM_ROM AM_MIRROR(0x1c00)
+	AM_RANGE(0x0000, 0x03ff) AM_ROM
 ADDRESS_MAP_END
 
 static ADDRESS_MAP_START(program_1_5k, AS_PROGRAM, 8, amis2000_device)
-	AM_RANGE(0x0000, 0x03ff) AM_ROM AM_MIRROR(0x1800)
-	AM_RANGE(0x0400, 0x05ff) AM_ROM AM_MIRROR(0x1a00)
+	AM_RANGE(0x0000, 0x03ff) AM_ROM
+	AM_RANGE(0x0400, 0x05ff) AM_ROM AM_MIRROR(0x200)
 ADDRESS_MAP_END
 
 
@@ -116,7 +117,7 @@ offs_t amis2000_device::disasm_disassemble(char *buffer, offs_t pc, const UINT8
 enum
 {
 	S2000_PC=1, S2000_BL, S2000_BU,
-	S2000_ACC, S2000_E, S2000_CARRY
+	S2000_ACC, S2000_E, S2000_CY
 };
 
 void amis2000_device::device_start()
@@ -138,9 +139,9 @@ void amis2000_device::device_start()
 	m_pc = 0;
 	m_ppr = 0;
 	m_pbr = 0;
-	m_pp_index = 0;
 	m_skip = false;
 	m_op = 0;
+	m_prev_op = 0;
 	m_f = 0;
 	m_carry = 0;
 	m_bl = 0;
@@ -157,9 +158,9 @@ void amis2000_device::device_start()
 	save_item(NAME(m_pc));
 	save_item(NAME(m_ppr));
 	save_item(NAME(m_pbr));
-	save_item(NAME(m_pp_index));
 	save_item(NAME(m_skip));
 	save_item(NAME(m_op));
+	save_item(NAME(m_prev_op));
 	save_item(NAME(m_f));
 	save_item(NAME(m_carry));
 	save_item(NAME(m_bl));
@@ -177,7 +178,7 @@ void amis2000_device::device_start()
 	state_add(S2000_BU,     "BU",     m_bu    ).formatstr("%01X");
 	state_add(S2000_ACC,    "ACC",    m_acc   ).formatstr("%01X");
 	state_add(S2000_E,      "E",      m_e     ).formatstr("%01X");
-	state_add(S2000_CARRY,  "CARRY",  m_carry ).formatstr("%01X");
+	state_add(S2000_CY,     "CY",     m_carry ).formatstr("%01X");
 
 	state_add(STATE_GENPC, "curpc", m_pc).formatstr("%04X").noshow();
 	state_add(STATE_GENFLAGS, "GENFLAGS", m_f).formatstr("%6s").noshow();
@@ -218,14 +219,8 @@ void amis2000_device::execute_run()
 	{
 		m_icount--;
 		
-		// increase PP prefix count
-		if ((m_op & 0xf0) == 0x60)
-		{
-			if (m_pp_index < 2)
-				m_pp_index++;
-		}
-		else
-			m_pp_index = 0;
+		// remember previous opcode
+		m_prev_op = m_op;
 
 		debugger_instruction_hook(this, m_pc);
 		m_op = m_program->read_byte(m_pc);
diff --git a/src/emu/cpu/amis2000/amis2000.h b/src/emu/cpu/amis2000/amis2000.h
index 966a85cd524..d8960bfd062 100644
--- a/src/emu/cpu/amis2000/amis2000.h
+++ b/src/emu/cpu/amis2000/amis2000.h
@@ -80,9 +80,9 @@ protected:
 	UINT16 m_pc;                // 13-bit program counter
 	UINT8 m_ppr;                // prepared page register (PP 1)
 	UINT8 m_pbr;                // prepared bank register (PP 2)
-	UINT8 m_pp_index;           // number of handled PP prefixes
 	bool m_skip;                // skip next opcode, including PP prefixes
 	UINT8 m_op;
+	UINT8 m_prev_op;            // previous opcode, needed for PP, LAI, LB*
 	UINT8 m_f;                  // generic flags: 2 on 2000/2150, 6 on 2200/2400
 	UINT8 m_carry;              // carry flag
 	UINT8 m_bl;                 // 4-bit ram index x
diff --git a/src/emu/cpu/amis2000/amis2000op.inc b/src/emu/cpu/amis2000/amis2000op.inc
index 97fa6b6db82..5a188a3f336 100644
--- a/src/emu/cpu/amis2000/amis2000op.inc
+++ b/src/emu/cpu/amis2000/amis2000op.inc
@@ -4,13 +4,13 @@
 
 UINT8 amis2000_device::ram_r()
 {
-	UINT16 address = m_bu << m_bu_bits | m_bl;
+	UINT16 address = m_bu << 4 | m_bl;
 	return m_data->read_byte(address) & 0xf;
 }
 
 void amis2000_device::ram_w(UINT8 data)
 {
-	UINT16 address = m_bu << m_bu_bits | m_bl;
+	UINT16 address = m_bu << 4 | m_bl;
 	m_data->write_byte(address, data & 0xf);
 }
 
@@ -44,10 +44,14 @@ void amis2000_device::op_illegal()
 void amis2000_device::op_lai()
 {
 	// LAI X: load ACC with X, select I and K inputs
-	UINT8 param = m_op & 0x0f;
-	m_acc = param;
-	m_i = m_read_i(0, 0xff) & param;
-	m_k = m_read_k(0, 0xff) & param;
+	// note: only execute the first one in a sequence of LAI
+	if ((m_prev_op & 0xf0) != (m_op & 0xf0))
+	{
+		UINT8 param = m_op & 0x0f;
+		m_acc = param;
+		m_i = m_read_i(0, 0xff) & param;
+		m_k = m_read_k(0, 0xff) & param;
+	}
 }
 
 void amis2000_device::op_lab()
@@ -89,33 +93,49 @@ void amis2000_device::op_xae()
 void amis2000_device::op_lbe()
 {
 	// LBE Y: load BU with Y, load BL with E
-	UINT8 param = m_op & 0x03;
-	m_bu = param & m_bu_mask;
-	m_bl = m_e;
+	// note: only execute the first one in a sequence of LB*
+	if ((m_prev_op & 0xf0) != (m_op & 0xf0))
+	{
+		UINT8 param = m_op & 0x03;
+		m_bu = param & m_bu_mask;
+		m_bl = m_e;
+	}
 }
 
 void amis2000_device::op_lbep()
 {
 	// LBEP Y: load BU with Y, load BL with E+1
-	UINT8 param = m_op & 0x03;
-	m_bu = param & m_bu_mask;
-	m_bl = m_e + 1;
+	// note: only execute the first one in a sequence of LB*
+	if ((m_prev_op & 0xf0) != (m_op & 0xf0))
+	{
+		UINT8 param = m_op & 0x03;
+		m_bu = param & m_bu_mask;
+		m_bl = m_e + 1;
+	}
 }
 
 void amis2000_device::op_lbz()
 {
 	// LBZ Y: load BU with Y, load BL with 0
-	UINT8 param = m_op & 0x03;
-	m_bu = param & m_bu_mask;
-	m_bl = 0;
+	// note: only execute the first one in a sequence of LB*
+	if ((m_prev_op & 0xf0) != (m_op & 0xf0))
+	{
+		UINT8 param = m_op & 0x03;
+		m_bu = param & m_bu_mask;
+		m_bl = 0;
+	}
 }
 
 void amis2000_device::op_lbf()
 {
 	// LBF Y: load BU with Y, load BL with 15
-	UINT8 param = m_op & 0x03;
-	m_bu = param & m_bu_mask;
-	m_bl = 0xf;
+	// note: only execute the first one in a sequence of LB*
+	if ((m_prev_op & 0xf0) != (m_op & 0xf0))
+	{
+		UINT8 param = m_op & 0x03;
+		m_bu = param & m_bu_mask;
+		m_bl = 0xf;
+	}
 }
 
 
@@ -279,7 +299,7 @@ void amis2000_device::op_pp()
 {
 	// PP _X: prepare page/bank with _X
 	UINT8 param = ~m_op & 0x0f;
-	if (m_pp_index == 0)
+	if ((m_prev_op & 0xf0) != (m_op & 0xf0))
 		m_ppr = param;
 	else
 		m_pbr = param & 7;
@@ -290,15 +310,12 @@ void amis2000_device::op_jmp()
 	// JMP X: jump to X(+PP)
 	UINT16 mask = 0x3f;
 	UINT16 param = m_op & mask;
-	if (m_pp_index > 0)
+	
+	// if previous opcode was PP, change PC high bits too
+	if ((m_prev_op & 0xf0) == 0x60)
 	{
-		param |= m_ppr << 6;
-		mask |= 0x3c0;
-	}
-	if (m_pp_index > 1)
-	{
-		param |= m_pbr << 10;
-		mask |= 0x1c00;
+		param |= (m_ppr << 6) | (m_pbr << 10);
+		mask = 0x1fff;
 	}
 	m_pc = (m_pc & ~mask) | param;
 }
@@ -308,13 +325,11 @@ void amis2000_device::op_jms()
 	// JMS X: call to X(+PP)
 	m_icount--;
 	push_callstack();
-	if (m_pp_index == 0)
-	{
-		// subroutines default location is page 15
-		m_ppr = 0xf;
-		m_pp_index++;
-	}
 	op_jmp();
+
+	// subroutines default location is page 15
+	if ((m_prev_op & 0xf0) != 0x60)
+		m_pc |= 0x3c0;
 }
 
 void amis2000_device::op_rt()
@@ -384,13 +399,13 @@ void amis2000_device::op_sos()
 void amis2000_device::op_tf1()
 {
 	// TF1: skip next on flag 1
-	m_skip = (m_f & 0x01);
+	m_skip = (m_f & 0x01) ? true : false;
 }
 
 void amis2000_device::op_tf2()
 {
 	// TF2: skip next on flag 2
-	m_skip = (m_f & 0x02);
+	m_skip = (m_f & 0x02) ? true : false;
 }
 
 
diff --git a/src/mess/drivers/wildfire.c b/src/mess/drivers/wildfire.c
index c4dce72cc1a..39db9be728f 100644
--- a/src/mess/drivers/wildfire.c
+++ b/src/mess/drivers/wildfire.c
@@ -31,6 +31,9 @@ public:
 	required_device<cpu_device> m_maincpu;
 	required_device<speaker_sound_device> m_speaker;
 
+	DECLARE_WRITE8_MEMBER(write_d);
+	DECLARE_WRITE16_MEMBER(write_a);
+
 	virtual void machine_start();
 };
 
@@ -41,7 +44,13 @@ public:
 
 ***************************************************************************/
 
-//..
+WRITE8_MEMBER(wildfire_state::write_d)
+{
+}
+
+WRITE16_MEMBER(wildfire_state::write_a)
+{
+}
 
 
 
@@ -52,6 +61,11 @@ public:
 ***************************************************************************/
 
 static INPUT_PORTS_START( wildfire )
+	PORT_START("IN1") // I
+	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON3 ) PORT_NAME("Shooter Button")
+	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_BUTTON1 ) PORT_NAME("Left Flipper")
+	PORT_BIT( 0x04, IP_ACTIVE_HIGH, IPT_BUTTON2 ) PORT_NAME("Right Flipper")
+	PORT_BIT( 0x08, IP_ACTIVE_HIGH, IPT_UNUSED )
 INPUT_PORTS_END
 
 
@@ -71,6 +85,9 @@ static MACHINE_CONFIG_START( wildfire, wildfire_state )
 
 	/* basic machine hardware */
 	MCFG_CPU_ADD("maincpu", AMI_S2150, MASTER_CLOCK)
+	MCFG_AMI_S2000_READ_I_CB(IOPORT("IN1"))
+	MCFG_AMI_S2000_WRITE_D_CB(WRITE8(wildfire_state, write_d))
+	MCFG_AMI_S2000_WRITE_A_CB(WRITE16(wildfire_state, write_a))
 
 	MCFG_DEFAULT_LAYOUT(layout_wildfire)