diff --git a/src/emu/cpu/amis2000/amis2000.c b/src/emu/cpu/amis2000/amis2000.c
index 0e8dae3b8b9..1d0f923a59e 100644
--- a/src/emu/cpu/amis2000/amis2000.c
+++ b/src/emu/cpu/amis2000/amis2000.c
@@ -16,7 +16,7 @@
 
 // S2000 is the most basic one, 64 nibbles internal RAM and 1KB internal ROM
 // S2150 increased RAM to 80 nibbles and ROM to 1.5KB
-// high-voltage output versions of these chips (S2000C and S2150C) are identical overall
+// high-voltage output versions of these chips (S2000A and S2150A) are identical overall
 const device_type AMI_S2000 = &device_creator<amis2000_device>;
 const device_type AMI_S2150 = &device_creator<amis2150_device>;
 
@@ -48,7 +48,8 @@ amis2000_device::amis2000_device(const machine_config &mconfig, const char *tag,
 	m_program_config("program", ENDIANNESS_BIG, 8, 13, 0, ADDRESS_MAP_NAME(program_1k)),
 	m_data_config("data", ENDIANNESS_BIG, 8, 6, 0, ADDRESS_MAP_NAME(data_64x4)),
 	m_bu_bits(2),
-	m_stack_bits(10),
+	m_callstack_bits(10),
+	m_callstack_depth(3),
 	m_read_k(*this),
 	m_read_i(*this),
 	m_read_d(*this),
@@ -57,12 +58,13 @@ amis2000_device::amis2000_device(const machine_config &mconfig, const char *tag,
 {
 }
 
-amis2000_device::amis2000_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, UINT8 bu_bits, UINT8 stack_bits, int prgwidth, address_map_constructor program, int datawidth, address_map_constructor data, const char *shortname, const char *source)
+amis2000_device::amis2000_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, UINT8 bu_bits, UINT8 callstack_bits, UINT8 callstack_depth, int prgwidth, address_map_constructor program, int datawidth, address_map_constructor data, const char *shortname, const char *source)
 	: cpu_device(mconfig, type, name, tag, owner, clock, shortname, source),
 	m_program_config("program", ENDIANNESS_BIG, 8, prgwidth, 0, program),
 	m_data_config("data", ENDIANNESS_BIG, 8, datawidth, 0, data),
 	m_bu_bits(bu_bits),
-	m_stack_bits(stack_bits),
+	m_callstack_bits(callstack_bits),
+	m_callstack_depth(callstack_depth),
 	m_read_k(*this),
 	m_read_i(*this),
 	m_read_d(*this),
@@ -72,7 +74,7 @@ amis2000_device::amis2000_device(const machine_config &mconfig, device_type type
 }
 
 amis2150_device::amis2150_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
-	: amis2000_device(mconfig, AMI_S2150, "AMI S2150", tag, owner, clock, 3, 11, 13, ADDRESS_MAP_NAME(program_1_5k), 7, ADDRESS_MAP_NAME(data_80x4), "amis2150", __FILE__)
+	: amis2000_device(mconfig, AMI_S2150, "AMI S2150", tag, owner, clock, 3, 11, 3, 13, ADDRESS_MAP_NAME(program_1_5k), 7, ADDRESS_MAP_NAME(data_80x4), "amis2150", __FILE__)
 {
 }
 
@@ -112,7 +114,7 @@ offs_t amis2000_device::disasm_disassemble(char *buffer, offs_t pc, const UINT8
 enum
 {
 	S2000_PC=1, S2000_BL, S2000_BU,
-	S2000_A, S2000_E
+	S2000_ACC, S2000_E
 };
 
 void amis2000_device::device_start()
@@ -127,34 +129,34 @@ void amis2000_device::device_start()
 	m_write_a.resolve_safe();
 
 	m_bu_mask = (1 << m_bu_bits) - 1;
-	m_stack_mask = (1 << m_stack_bits) - 1;
+	m_callstack_mask = (1 << m_callstack_bits) - 1;
 
 	// zerofill
-	m_stack[0] = m_stack[1] = m_stack[2] = 0;
+	memset(m_callstack, 0, sizeof(m_callstack));
 	m_pc = 0;
 	m_op = 0;
 	m_f = 0;
 	m_bl = 0;
 	m_bu = 0;
-	m_a = 0;
+	m_acc = 0;
 	m_e = 0;
 
 	// register for savestates
-	save_item(NAME(m_stack));
+	save_item(NAME(m_callstack));
 	save_item(NAME(m_pc));
 	save_item(NAME(m_op));
 	save_item(NAME(m_f));
 	save_item(NAME(m_bl));
 	save_item(NAME(m_bu));
-	save_item(NAME(m_a));
+	save_item(NAME(m_acc));
 	save_item(NAME(m_e));
 
 	// register state for debugger
 	state_add(S2000_PC,     "PC",     m_pc    ).formatstr("%04X");
 	state_add(S2000_BL,     "BL",     m_bl    ).formatstr("%01X");
 	state_add(S2000_BU,     "BU",     m_bu    ).formatstr("%01X");
-	state_add(S2000_A,      "A",      m_a     ).formatstr("%01X");
-	state_add(S2000_E,      "E",      m_a     ).formatstr("%01X");
+	state_add(S2000_ACC,    "ACC",    m_acc   ).formatstr("%01X");
+	state_add(S2000_E,      "E",      m_e     ).formatstr("%01X");
 
 	state_add(STATE_GENPC, "curpc", m_pc).formatstr("%04X").noshow();
 	state_add(STATE_GENFLAGS, "GENFLAGS", m_f).formatstr("%6s").noshow();
@@ -183,7 +185,7 @@ void amis2000_device::device_reset()
 
 void amis2000_device::execute_run()
 {
-	do
+	while (m_icount > 0)
 	{
 		m_icount--;
 
@@ -191,10 +193,76 @@ void amis2000_device::execute_run()
 		m_op = m_program->read_byte(m_pc);
 		m_pc = (m_pc + 1) & 0x1fff;
 
-		switch (m_op)
+		switch (m_op & 0xf0)
 		{
-			default: break;
-		}
+			case 0x50: op_adis(); break;
+			case 0x60: op_pp(); break;
+			case 0x70: op_lai(); break;
 
-	} while (m_icount > 0);
+			case 0x80: case 0x90: case 0xa0: case 0xb0: op_jms(); break;
+			case 0xc0: case 0xd0: case 0xe0: case 0xf0: op_jmp(); break;
+
+			default:
+				switch (m_op)
+				{
+			case 0x00: op_nop(); break;
+			case 0x01: op_illegal(); break; // reserved for devkit-use
+			case 0x02: op_rt(); break;
+			case 0x03: op_rts(); break;
+			case 0x04: op_psh(); break;
+			case 0x05: op_psl(); break;
+			case 0x06: op_and(); break;
+			case 0x07: op_sos(); break;
+			case 0x08: op_sbe(); break;
+			case 0x09: op_szc(); break;
+			case 0x0a: op_stc(); break;
+			case 0x0b: op_rsc(); break;
+			case 0x0c: op_lae(); break;
+			case 0x0d: op_xae(); break;
+			case 0x0e: op_inp(); break;
+			case 0x0f: op_eur(); break;
+			case 0x10: op_cma(); break;
+			case 0x11: op_xabu(); break;
+			case 0x12: op_lab(); break;
+			case 0x13: op_xab(); break;
+			case 0x14: op_adcs(); break;
+			case 0x15: op_xor(); break;
+			case 0x16: op_add(); break;
+			case 0x17: op_sam(); break;
+			case 0x18: op_disb(); break;
+			case 0x19: op_mvs(); break;
+			case 0x1a: op_out(); break;
+			case 0x1b: op_disn(); break;
+
+			case 0x28: op_szk(); break;
+			case 0x29: op_szi(); break;
+			case 0x2a: op_rf1(); break;
+			case 0x2b: op_sf1(); break;
+			case 0x2c: op_rf2(); break;
+			case 0x2d: op_sf2(); break;
+			case 0x2e: op_tf1(); break;
+			case 0x2f: op_tf2(); break;
+			
+			default:
+				switch (m_op & 0xfc)
+				{
+			case 0x1c: op_szm(); break;
+			case 0x20: op_stm(); break;
+			case 0x24: op_rsm(); break;
+
+			case 0x30: op_xci(); break;
+			case 0x34: op_xcd(); break;
+			case 0x38: op_xc(); break;
+			case 0x3c: op_lam(); break;
+			case 0x40: op_lbz(); break;
+			case 0x44: op_lbf(); break;
+			case 0x48: op_lbe(); break;
+			case 0x4c: op_lbep(); break;
+				}
+				break;
+
+				}
+				break;
+		} // big switch
+	}
 }
diff --git a/src/emu/cpu/amis2000/amis2000.h b/src/emu/cpu/amis2000/amis2000.h
index 8bcefd65804..5cf7761c27e 100644
--- a/src/emu/cpu/amis2000/amis2000.h
+++ b/src/emu/cpu/amis2000/amis2000.h
@@ -36,7 +36,7 @@ class amis2000_device : public cpu_device
 public:
 	// construction/destruction
 	amis2000_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
-	amis2000_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, UINT8 bu_bits, UINT8 stack_bits, int prgwidth, address_map_constructor program, int datawidth, address_map_constructor data, const char *shortname, const char *source);
+	amis2000_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, UINT8 bu_bits, UINT8 callstack_bits, UINT8 callstack_depth, int prgwidth, address_map_constructor program, int datawidth, address_map_constructor data, const char *shortname, const char *source);
 
 	// static configuration helpers
 	template<class _Object> static devcb_base &set_read_k_callback(device_t &device, _Object object) { return downcast<amis2000_device &>(device).m_read_k.set_callback(object); }
@@ -72,16 +72,17 @@ protected:
 	
 	UINT8 m_bu_bits;
 	UINT16 m_bu_mask;
-	UINT8 m_stack_bits;
-	UINT16 m_stack_mask;
-	UINT16 m_stack[3];
+	UINT8 m_callstack_bits;
+	UINT16 m_callstack_mask;
+	UINT8 m_callstack_depth;    // callstack levels: 3 on 2000/2150, 5 on 2200/2400
+	UINT16 m_callstack[5];      // max 5
 
 	UINT16 m_pc;
 	UINT8 m_op;
-	UINT8 m_f;
-	UINT8 m_bl;
-	UINT8 m_bu;
-	UINT8 m_a;
+	UINT8 m_f;                  // generic flags: 2 on 2000/2150, 6 on 2200/2400
+	UINT8 m_bl;                 // 4-bit ram index x
+	UINT8 m_bu;                 // 2/3-bit ram index y
+	UINT8 m_acc;
 	UINT8 m_e;
 
 	devcb_read8 m_read_k;
@@ -91,6 +92,65 @@ protected:
 	devcb_write16 m_write_a;
 
 	int m_icount;
+	
+	void op_illegal();
+	
+	void op_lai();
+	void op_lab();
+	void op_lae();
+	void op_xab();
+	void op_xabu();
+	void op_xae();
+	void op_lbe();
+	void op_lbep();
+	void op_lbz();
+	void op_lbf();
+
+	void op_lam();
+	void op_xc();
+	void op_xci();
+	void op_xcd();
+	void op_stm();
+	void op_rsm();
+
+	void op_inp();
+	void op_out();
+	void op_disb();
+	void op_disn();
+	void op_mvs();
+	void op_psh();
+	void op_psl();
+	void op_eur();
+
+	void op_pp();
+	void op_jmp();
+	void op_jms();
+	void op_rt();
+	void op_rts();
+	void op_nop();
+
+	void op_szc();
+	void op_szm();
+	void op_szi();
+	void op_szk();
+	void op_sbe();
+	void op_sam();
+	void op_sos();
+	void op_tf1();
+	void op_tf2();
+
+	void op_adcs();
+	void op_adis();
+	void op_add();
+	void op_and();
+	void op_xor();
+	void op_stc();
+	void op_rsc();
+	void op_cma();
+	void op_sf1();
+	void op_rf1();
+	void op_sf2();
+	void op_rf2();
 };
 
 
diff --git a/src/emu/cpu/amis2000/amis2000op.inc b/src/emu/cpu/amis2000/amis2000op.inc
index 0113dcdad8e..a0b219dbd72 100644
--- a/src/emu/cpu/amis2000/amis2000op.inc
+++ b/src/emu/cpu/amis2000/amis2000op.inc
@@ -1 +1,331 @@
 // AMI S2000 opcode handlers
+
+// internal helpers
+
+void amis2000_device::op_illegal()
+{
+	logerror("%s unknown opcode $%02X at $%04X\n", tag(), m_op, m_pc);
+}
+
+
+// Register Instructions
+
+void amis2000_device::op_lai()
+{
+	// LAI X: load ACC with X, select I and K inputs
+	op_illegal();
+}
+
+void amis2000_device::op_lab()
+{
+	// LAB: load ACC with BL
+	op_illegal();
+}
+
+void amis2000_device::op_lae()
+{
+	// LAE: load ACC with E
+	op_illegal();
+}
+
+void amis2000_device::op_xab()
+{
+	// XAB: exchange ACC with BL
+	op_illegal();
+}
+
+void amis2000_device::op_xabu()
+{
+	// XABU: exchange ACC with BU
+	op_illegal();
+}
+
+void amis2000_device::op_xae()
+{
+	// XAE: exchange ACC with E
+	op_illegal();
+}
+
+void amis2000_device::op_lbe()
+{
+	// LBE Y: load BU with Y, load BL with E
+	op_illegal();
+}
+
+void amis2000_device::op_lbep()
+{
+	// LBEP Y: load BU with Y, load BL with E+1
+	op_illegal();
+}
+
+void amis2000_device::op_lbz()
+{
+	// LBZ Y: load BU with Y, load BL with 0
+	op_illegal();
+}
+
+void amis2000_device::op_lbf()
+{
+	// LBF Y: load BU with Y, load BL with 15
+	op_illegal();
+}
+
+
+// RAM Instructions
+
+void amis2000_device::op_lam()
+{
+	// LAM _Y: load ACC with RAM, xor BU with _Y
+	op_illegal();
+}
+
+void amis2000_device::op_xc()
+{
+	// XC _Y: exchange ACC with RAM, xor BU with _Y
+	op_illegal();
+}
+
+void amis2000_device::op_xci()
+{
+	// XCI _Y: exchange ACC with RAM, increment BL(skip next on carry), xor BU with _Y
+	op_illegal();
+}
+
+void amis2000_device::op_xcd()
+{
+	// XCD _Y: exchange ACC with RAM, decrement BL(skip next on carry), xor BU with _Y
+	op_illegal();
+}
+
+void amis2000_device::op_stm()
+{
+	// STM Z: set RAM bit Z
+	op_illegal();
+}
+
+void amis2000_device::op_rsm()
+{
+	// RSM Z: reset RAM bit Z
+	op_illegal();
+}
+
+
+// Input/Output Instructions
+
+void amis2000_device::op_inp()
+{
+	// INP: input D-pins to ACC and RAM
+	op_illegal();
+}
+
+void amis2000_device::op_out()
+{
+	// OUT: pulse output ACC and RAM to D-pins
+	op_illegal();
+}
+
+void amis2000_device::op_disb()
+{
+	// DISB: set D-latch to ACC and RAM directly
+	op_illegal();
+}
+
+void amis2000_device::op_disn()
+{
+	// DISN: set D-latch to ACC+carry via segment decoder
+	op_illegal();
+}
+
+void amis2000_device::op_mvs()
+{
+	// MVS: output master strobe latch to A-pins
+	op_illegal();
+}
+
+void amis2000_device::op_psh()
+{
+	// PSH: preset high(BL) master strobe latch
+	op_illegal();
+}
+
+void amis2000_device::op_psl()
+{
+	// PSL: preset low(BL) master strobe latch
+	op_illegal();
+}
+
+void amis2000_device::op_eur()
+{
+	// EUR: set timer frequency(European) and D-latch polarity
+	op_illegal();
+}
+
+
+// Program Control Instructions
+
+void amis2000_device::op_pp()
+{
+	// PP _X: prepare page/bank with _X
+	op_illegal();
+}
+
+void amis2000_device::op_jmp()
+{
+	// JMP X: jump to X(+PP)
+	op_illegal();
+}
+
+void amis2000_device::op_jms()
+{
+	// JMS X: call to X(+PP)
+	op_illegal();
+}
+
+void amis2000_device::op_rt()
+{
+	// RT: return from subroutine
+	op_illegal();
+}
+
+void amis2000_device::op_rts()
+{
+	// RTS: return from subroutine and skip next
+	op_illegal();
+}
+
+void amis2000_device::op_nop()
+{
+	// NOP: no operation
+}
+
+
+// Skip Instructions
+
+void amis2000_device::op_szc()
+{
+	// SZC: skip next on zero(no) carry
+	op_illegal();
+}
+
+void amis2000_device::op_szm()
+{
+	// SZM Z: skip next on zero RAM bit Z
+	op_illegal();
+}
+
+void amis2000_device::op_szi()
+{
+	// SZI: skip next on zero I pin(s)
+	op_illegal();
+}
+
+void amis2000_device::op_szk()
+{
+	// SZK: skip next on zero K pin(s)
+	op_illegal();
+}
+
+void amis2000_device::op_sbe()
+{
+	// SBE: skip next on BL equ E
+	op_illegal();
+}
+
+void amis2000_device::op_sam()
+{
+	// SAM: skip next on ACC equ RAM
+	op_illegal();
+}
+
+void amis2000_device::op_sos()
+{
+	// SOS: skip next on SF(timer output), clear SF
+	op_illegal();
+}
+
+void amis2000_device::op_tf1()
+{
+	// TF1: skip next on flag 1
+	op_illegal();
+}
+
+void amis2000_device::op_tf2()
+{
+	// TF2: skip next on flag 2
+	op_illegal();
+}
+
+
+// Arithmetic and Logical Instructions
+
+void amis2000_device::op_adcs()
+{
+	// ADCS: add RAM to ACC+carry, skip next on no carry
+	op_illegal();
+}
+
+void amis2000_device::op_adis()
+{
+	// ADIS X: add X to ACC, skip next on no carry
+	op_illegal();
+}
+
+void amis2000_device::op_add()
+{
+	// ADD: add RAM to ACC
+	op_illegal();
+}
+
+void amis2000_device::op_and()
+{
+	// AND: and ACC with RAM
+	op_illegal();
+}
+
+void amis2000_device::op_xor()
+{
+	// XOR: xor ACC with RAM
+	op_illegal();
+}
+
+void amis2000_device::op_stc()
+{
+	// STC: set carry
+	op_illegal();
+}
+
+void amis2000_device::op_rsc()
+{
+	// RSC: reset carry
+	op_illegal();
+}
+
+void amis2000_device::op_cma()
+{
+	// CMA: complement ACC
+	op_illegal();
+}
+
+void amis2000_device::op_sf1()
+{
+	// SF1: set flag 1
+	op_illegal();
+}
+
+void amis2000_device::op_rf1()
+{
+	// RF1: reset flag 1
+	op_illegal();
+}
+
+void amis2000_device::op_sf2()
+{
+	// SF2: set flag 2
+	op_illegal();
+}
+
+void amis2000_device::op_rf2()
+{
+	// RF2: reset flag 2
+	op_illegal();
+}
diff --git a/src/mess/drivers/wildfire.c b/src/mess/drivers/wildfire.c
index b846a89c039..c4dce72cc1a 100644
--- a/src/mess/drivers/wildfire.c
+++ b/src/mess/drivers/wildfire.c
@@ -14,7 +14,8 @@
 
 #include "wildfire.lh"
 
-// master clock is MCU internal, default frequency of 850kHz
+// master clock is a single stage RC oscillator: R=?K, C=?pf,
+// S2150 default frequency is 850kHz
 #define MASTER_CLOCK (850000)