sm500: added device start/reset (nw)

src/devices/cpu/sm510/sm500.h

@@ -78,6 +78,8 @@ public:
 protected:
 	sm500_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, int stack_levels, int o_mask, int prgwidth, address_map_constructor program, int datawidth, address_map_constructor data);
 
+	virtual void device_start() override;
+	virtual void device_reset() override;
 	virtual offs_t disasm_disassemble(std::ostream &stream, offs_t pc, const u8 *oprom, const u8 *opram, u32 options) override;
 	virtual void execute_one() override;
 	virtual void get_opcode_param() override;
@@ -124,6 +126,8 @@ protected:
 	virtual void op_exksa();
 	virtual void op_exkfa();
 
+	virtual void op_idiv() override;
+
 	virtual void op_rmf();
 	virtual void op_smf();
 	virtual void op_comcn();

src/devices/cpu/sm510/sm500core.cpp

@@ -44,6 +44,53 @@ sm500_device::sm500_device(const machine_config &mconfig, device_type type, cons
 }
 
 
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void sm500_device::device_start()
+{
+	// common init (not everything is used though)
+	sm510_base_device::device_start();
+	
+	// init/zerofill
+	memset(m_ox, 0, sizeof(m_ox));
+	memset(m_o, 0, sizeof(m_o));
+	m_cn = 0;
+	m_mx = 0;
+	m_cb = 0;
+	m_s = 0;
+	m_rsub = false;
+
+	// register for savestates
+	save_item(NAME(m_ox));
+	save_item(NAME(m_o));
+	save_item(NAME(m_cn));
+	save_item(NAME(m_mx));
+	save_item(NAME(m_cb));
+	save_item(NAME(m_s));
+	save_item(NAME(m_rsub));
+}
+
+
+
+//-------------------------------------------------
+//  device_reset - device-specific reset
+//-------------------------------------------------
+
+void sm500_device::device_reset()
+{
+	// common reset
+	sm510_base_device::device_reset();
+	
+	// SM500 specific
+	op_idiv();
+	m_cb = 0;
+	m_rsub = false;
+}
+
+
+
 // disasm
 offs_t sm500_device::disasm_disassemble(std::ostream &stream, offs_t pc, const u8 *oprom, const u8 *opram, u32 options)
 {

src/devices/cpu/sm510/sm500op.cpp

@@ -183,6 +183,12 @@ void sm500_device::op_exkfa()
 
 // Divider manipulation instructions
 
+void sm500_device::op_idiv()
+{
+	// IDIV: reset divider low 9 bits
+	m_div &= 0x3f;
+}
+
 
 // Bit manipulation instructions
 

src/devices/cpu/sm510/sm510op.cpp

@@ -250,6 +250,7 @@ void sm510_base_device::op_atr()
 {
 	// ATR: output ACC to R
 	m_r = m_acc;
+	clock_melody();
 }