diff --git a/src/emu/cpu/sm510/sm510.c b/src/emu/cpu/sm510/sm510.c
index ce84fba789c..c91f152fa77 100644
--- a/src/emu/cpu/sm510/sm510.c
+++ b/src/emu/cpu/sm510/sm510.c
@@ -47,23 +47,6 @@ sm510_device::sm510_device(const machine_config &mconfig, const char *tag, devic
 
 
 // disasm
-void sm510_base_device::state_string_export(const device_state_entry &entry, std::string &str)
-{
-	#if 0
-	switch (entry.index())
-	{
-		case STATE_GENFLAGS:
-			strprintf(str, "%c%c",
-				m_c ? 'C':'c',
-				m_s ? 'S':'s'
-			);
-			break;
-
-		default: break;
-	}
-	#endif
-}
-
 offs_t sm510_base_device::disasm_disassemble(char *buffer, offs_t pc, const UINT8 *oprom, const UINT8 *opram, UINT32 options)
 {
 	extern CPU_DISASSEMBLE(sm510);
@@ -124,7 +107,7 @@ void sm510_base_device::device_start()
 	state_add(SM510_BM,  "BM",  m_bm).formatstr("%01X");
 
 	state_add(STATE_GENPC, "curpc", m_pc).formatstr("%04X").noshow();
-	state_add(STATE_GENFLAGS, "GENFLAGS", m_pc).formatstr("%2s").noshow();
+	state_add(STATE_GENFLAGS, "GENFLAGS", m_c).formatstr("%1s").noshow();
 
 	m_icountptr = &m_icount;
 }
@@ -137,7 +120,10 @@ void sm510_base_device::device_start()
 
 void sm510_base_device::device_reset()
 {
-	m_pc = 0x37 << 6;
+	m_skip = false;
+	m_op = m_prev_op = 0;
+	do_branch(3, 7, 0);
+	m_prev_pc = m_pc;
 }
 
 
@@ -156,10 +142,10 @@ inline void sm510_base_device::increment_pc()
 
 void sm510_base_device::get_opcode_param()
 {
-	// LBL, TL, TML, TM opcodes are 2 bytes
-	if (m_op == 0x5f || (m_op & 0xf0) == 0x70 || m_op >= 0xc0)
+	// LBL, TL, TML opcodes are 2 bytes
+	if (m_op == 0x5f || (m_op & 0xf0) == 0x70)
 	{
-		m_icount -= 2; // guessed
+		m_icount--;
 		m_param = m_program->read_byte(m_pc);
 		increment_pc();
 	}
@@ -175,12 +161,19 @@ void sm510_base_device::execute_run()
 
 		// fetch next opcode
 		debugger_instruction_hook(this, m_pc);
-		m_icount -= 2; // 61us typical
+		m_icount--;
 		m_op = m_program->read_byte(m_pc);
 		increment_pc();
 		get_opcode_param();
 
-		// handle opcode
+		// handle opcode if it's not skipped
+		if (m_skip)
+		{
+			m_skip = false;
+			m_op = 0; // fake nop
+		}
+		else //execute_one();
+
 		switch (m_op & 0xf0)
 		{
 			case 0x20: op_lax(); break;
diff --git a/src/emu/cpu/sm510/sm510.h b/src/emu/cpu/sm510/sm510.h
index ffb7e3561a1..379bc13c314 100644
--- a/src/emu/cpu/sm510/sm510.h
+++ b/src/emu/cpu/sm510/sm510.h
@@ -42,6 +42,8 @@ protected:
 	virtual void device_reset();
 
 	// device_execute_interface overrides
+	virtual UINT64 execute_clocks_to_cycles(UINT64 clocks) const { return (clocks + 2 - 1) / 2; } // default 2 cycles per machine cycle
+	virtual UINT64 execute_cycles_to_clocks(UINT64 cycles) const { return (cycles * 2); } // "
 	virtual UINT32 execute_min_cycles() const { return 1; }
 	virtual UINT32 execute_max_cycles() const { return 2; }
 	virtual UINT32 execute_input_lines() const { return 1; }
@@ -55,7 +57,6 @@ protected:
 	virtual UINT32 disasm_min_opcode_bytes() const { return 1; }
 	virtual UINT32 disasm_max_opcode_bytes() const { return 2; }
 	virtual offs_t disasm_disassemble(char *buffer, offs_t pc, const UINT8 *oprom, const UINT8 *opram, UINT32 options);
-	void state_string_export(const device_state_entry &entry, std::string &str);
 
 	address_space_config m_program_config;
 	address_space_config m_data_config;
@@ -93,6 +94,8 @@ protected:
 	void ram_w(UINT8 data);
 	void pop_stack();
 	void push_stack();
+	void do_branch(UINT8 pu, UINT8 pm, UINT8 pl);
+	UINT8 bitmask(UINT8 param);
 
 	// opcode handlers
 	void op_lb();
diff --git a/src/emu/cpu/sm510/sm510d.c b/src/emu/cpu/sm510/sm510d.c
index 71d32fa332d..dffd5e1530c 100644
--- a/src/emu/cpu/sm510/sm510d.c
+++ b/src/emu/cpu/sm510/sm510d.c
@@ -40,7 +40,7 @@ static const UINT8 s_bits[] =
 {
 	0,
 	4, 8, 0, 0, 0, 0,
-	0, 0, 0, 4+8, 2+8, 6+8, 6,
+	0, 0, 0, 4+8, 2+8, 6, 6,
 	2, 0, 2, 2, 2, 4, 0, 0,
 	0, 0, 0, 0, 0,
 	0, 0, 4, 0, 0, 0, 0,
@@ -133,15 +133,11 @@ CPU_DISASSEMBLE(sm510)
 		{
 			dst += sprintf(dst, "$%02X", param);
 		}
-		else if (instr == mTL || instr == mTML)
+		else
 		{
-			UINT16 address = (param << 4 & 0xc00) | (mask << 6 & 0x3c0) | (param & 0x3f);
+			UINT16 address = (param << 4 & 0xc00) | (mask << 6 & 0x3c0) | (param & 0x03f);
 			dst += sprintf(dst, "$%03X", address);
 		}
-		else if (instr == mTM)
-		{
-			//todo
-		}
 	}
 	
 	return len | s_flags[instr] | DASMFLAG_SUPPORTED;
diff --git a/src/emu/cpu/sm510/sm510op.inc b/src/emu/cpu/sm510/sm510op.inc
index d8e4368c4c2..b9583694849 100644
--- a/src/emu/cpu/sm510/sm510op.inc
+++ b/src/emu/cpu/sm510/sm510op.inc
@@ -7,13 +7,15 @@
 
 inline UINT8 sm510_base_device::ram_r()
 {
-	UINT8 address = (m_bm << 4 | m_bl) & m_datamask;
+	int bmh = (m_prev_op == 0x02) ? (1 << (m_datawidth-1)) : 0; // from SBM
+	UINT8 address = (bmh | m_bm << 4 | m_bl) & m_datamask;
 	return m_data->read_byte(address) & 0xf;
 }
 
 inline void sm510_base_device::ram_w(UINT8 data)
 {
-	UINT8 address = (m_bm << 4 | m_bl) & m_datamask;
+	int bmh = (m_prev_op == 0x02) ? (1 << (m_datawidth-1)) : 0; // from SBM
+	UINT8 address = (bmh | m_bm << 4 | m_bl) & m_datamask;
 	m_data->write_byte(address, data & 0xf);
 }
 
@@ -31,6 +33,18 @@ void sm510_base_device::push_stack()
 	m_stack[0] = m_pc;
 }
 
+inline void sm510_base_device::do_branch(UINT8 pu, UINT8 pm, UINT8 pl)
+{
+	// set new PC(Pu/Pm/Pl)
+	m_pc = ((pu << 10 & 0xc00) | (pm << 6 & 0x3c0) | (pl & 0x03f)) & m_prgmask;
+}
+
+inline UINT8 sm510_base_device::bitmask(UINT8 param)
+{
+	// bitmask from immediate opcode param
+	return 1 << (param & 3);
+}
+
 
 
 // instruction set
@@ -46,13 +60,14 @@ void sm510_base_device::op_lb()
 void sm510_base_device::op_lbl()
 {
 	// LBL xy: load BM/BL with 8-bit immediate value
-	op_illegal();
+	m_bl = m_param & 0xf;
+	m_bm = (m_param & m_datamask) >> 4;
 }
 
 void sm510_base_device::op_sbm()
 {
-	// SBM: set BM high bit for next opcode
-	op_illegal();
+	// SBM: set BM high bit for next opcode - handled in ram_r/w
+	assert(m_op == 0x02);
 }
 
 void sm510_base_device::op_exbla()
@@ -82,7 +97,7 @@ void sm510_base_device::op_decb()
 
 void sm510_base_device::op_atpl()
 {
-	// ATPL: load PC low bits with ACC
+	// ATPL: load Pl(PC low bits) with ACC
 	m_pc = (m_pc & ~0xf) | m_acc;
 }
 
@@ -99,29 +114,34 @@ void sm510_base_device::op_rtn1()
 	m_skip = true;
 }
 
+void sm510_base_device::op_t()
+{
+	// T xy: jump(transfer) within current page
+	m_pc = (m_pc & ~0x3f) | (m_op & 0x3f);
+}
+
 void sm510_base_device::op_tl()
 {
-	// TL xyz: longjump
-	op_illegal();
+	// TL xyz: long jump
+	do_branch(m_param >> 6 & 3, m_op & 0xf, m_param & 0x3f);
 }
 
 void sm510_base_device::op_tml()
 {
-	// TML xyz: x
-	op_illegal();
+	// TML xyz: long call
+	push_stack();
+	do_branch(m_param >> 6 & 3, m_op & 3, m_param & 0x3f);
 }
 
 void sm510_base_device::op_tm()
 {
-	// TM xyz: x
-	op_illegal();
+	// TM x: indirect subroutine call, pointers(IDX) are in page 0
+	m_icount--;
+	push_stack();
+	UINT8 idx = m_program->read_byte(m_op & 0x3f);
+	do_branch(idx >> 6 & 3, 4, idx & 0x3f);
 }
 
-void sm510_base_device::op_t()
-{
-	// T xy: jump within current page
-	m_pc = (m_pc & ~0x3f) | (m_op & 0x3f);
-}
 
 
 // Data transfer instructions
@@ -236,7 +256,7 @@ void sm510_base_device::op_adx()
 {
 	// ADX x: add immediate value to ACC, skip next on carry
 	m_acc += (m_op & 0xf);
-	m_skip = (m_acc & 0x10) ? true : false;
+	m_skip = ((m_acc & 0x10) != 0);
 	m_acc &= 0xf;
 }
 
@@ -248,10 +268,10 @@ void sm510_base_device::op_coma()
 
 void sm510_base_device::op_rot()
 {
-	// ROT: rotate ACC left through carry
-	m_acc = m_acc << 1 | m_c;
-	m_c = m_acc >> 4 & 1;
-	m_acc &= 0xf;
+	// ROT: rotate ACC right through carry
+	UINT8 c = m_acc & 1;
+	m_acc = m_acc >> 1 | m_c << 3;
+	m_c = c;
 }
 
 void sm510_base_device::op_rc()
@@ -290,7 +310,7 @@ void sm510_base_device::op_tam()
 void sm510_base_device::op_tmi()
 {
 	// TMI x: skip next if RAM bit is set
-	m_skip = (ram_r() & 1 << (m_op & 3)) ? true : false;
+	m_skip = ((ram_r() & bitmask(m_op)) != 0);
 }
 
 void sm510_base_device::op_ta0()
@@ -335,13 +355,13 @@ void sm510_base_device::op_tf4()
 void sm510_base_device::op_rm()
 {
 	// RM x: reset RAM bit
-	ram_w(ram_r() & ~(1 << (m_op & 3)));
+	ram_w(ram_r() & ~bitmask(m_op));
 }
 
 void sm510_base_device::op_sm()
 {
 	// SM x: set RAM bit
-	ram_w(ram_r() | (1 << (m_op & 3)));
+	ram_w(ram_r() | bitmask(m_op));
 }