i8089.c: go thru initialization

src/emu/machine/i8089.c

@@ -14,6 +14,50 @@
 #define VERBOSE 1
 
 
+//**************************************************************************
+//  I/O CHANNEL
+//**************************************************************************
+
+const device_type I8089_CHANNEL = &device_creator<i8089_channel>;
+
+class i8089_channel : public device_t,
+                      public device_execute_interface
+{
+public:
+	// construction/destruction
+	i8089_channel(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
+
+protected:
+	// device-level overrides
+	virtual void device_start();
+	virtual void execute_run();
+
+	int m_icount;
+};
+
+i8089_channel::i8089_channel(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
+	device_t(mconfig, I8089_CHANNEL, "Intel 8089 I/O Channel", tag, owner, clock, "i8089_channel", __FILE__),
+	device_execute_interface(mconfig, *this),
+	m_icount(0)
+{
+}
+
+void i8089_channel::device_start()
+{
+	// set our instruction counter
+	m_icountptr = &m_icount;
+}
+
+void i8089_channel::execute_run()
+{
+	do
+	{
+		m_icount--;
+	}
+	while (m_icount > 0);
+}
+
+
 //**************************************************************************
 //  DEVICE DEFINITIONS
 //**************************************************************************
@@ -31,8 +75,17 @@ const device_type I8089 = &device_creator<i8089_device>;
 
 i8089_device::i8089_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
 	device_t(mconfig, I8089, "Intel 8089", tag, owner, clock, "i8089", __FILE__),
+	m_ch1(*this, "1"),
+	m_ch2(*this, "2"),
 	m_write_sintr1(*this),
-	m_write_sintr2(*this)
+	m_write_sintr2(*this),
+	m_16bit_system(false),
+	m_16bit_remote(false),
+	m_master(false),
+	m_request_grant(false),
+	m_control_block(0),
+	m_ca(0),
+	m_sel(0)
 {
 }
 
@@ -48,9 +101,22 @@ void i8089_device::static_set_cputag(device_t &device, const char *tag)
 
 void i8089_device::device_start()
 {
+	// make sure our channels have been setup first
+	if (!m_ch1->started() || !m_ch2->started())
+		throw device_missing_dependencies();
+
 	// resolve callbacks
 	m_write_sintr1.resolve_safe();
 	m_write_sintr2.resolve_safe();
+
+	// get pointers to memory
+	device_t *cpu = machine().device(m_cputag);
+	m_mem = &cpu->memory().space(AS_PROGRAM);
+	m_io = &cpu->memory().space(AS_IO);
+
+	// initialize channel clock
+	m_ch1->set_unscaled_clock(clock());
+	m_ch2->set_unscaled_clock(clock());
 }
 
 //-------------------------------------------------
@@ -59,6 +125,85 @@ void i8089_device::device_start()
 
 void i8089_device::device_reset()
 {
+	m_initialized = false;
+}
+
+//-------------------------------------------------
+//  machine_config_additions - device-specific
+//  machine configurations
+//-------------------------------------------------
+
+static MACHINE_CONFIG_FRAGMENT( i8089 )
+	MCFG_DEVICE_ADD("1", I8089_CHANNEL, 0)
+	MCFG_DEVICE_ADD("2", I8089_CHANNEL, 0)
+MACHINE_CONFIG_END
+
+machine_config_constructor i8089_device::device_mconfig_additions() const
+{
+	return MACHINE_CONFIG_NAME( i8089 );
+}
+
+
+//**************************************************************************
+//  IMPLEMENTATION
+//**************************************************************************
+
+void i8089_device::initialize()
+{
+	assert(!m_initialized);
+
+	// get system bus width
+	UINT8 sys_bus = m_mem->read_byte(0xffff6);
+	m_16bit_system = BIT(sys_bus, 0);
+
+	// get system configuration block address
+	UINT16 scb_offset = read_word(0xffff8);
+	UINT16 scb_segment = read_word(0xffffa);
+	offs_t scb_address = (scb_segment << 4) + scb_offset;
+
+	// get system operation command
+	UINT16 soc = read_word(scb_address);
+	m_16bit_remote = BIT(soc, 0);
+	m_request_grant = BIT(soc, 1);
+	m_master = !m_sel;
+
+	UINT16 cb_offset = read_word(scb_address + 2);
+	UINT16 cb_segment = read_word(scb_address + 4);
+	m_control_block = (cb_segment << 4) + cb_offset;
+
+	// todo: set/clear busy
+	m_initialized = true;
+
+	// output some debug info
+	if (VERBOSE)
+	{
+		logerror("%s('%s'): initializing\n", shortname(), basetag());
+		logerror("%s('%s'): %s system bus\n", shortname(), basetag(), m_16bit_system ? "16-bit" : "8-bit");
+		logerror("%s('%s'): system configuration block location: %06x\n", shortname(), basetag(), scb_address);
+		logerror("%s('%s'): %s remote bus\n", shortname(), basetag(), m_16bit_remote ? "16-bit" : "8-bit");
+		logerror("%s('%s'): request/grant: %d\n", shortname(), basetag(), m_request_grant);
+		logerror("%s('%s'): is %s\n", shortname(), basetag(), m_master ? "master" : "slave");
+		logerror("%s('%s'): channel control block location: %06x\n", shortname(), basetag(), m_control_block);
+	}
+}
+
+UINT16 i8089_device::read_word(offs_t address)
+{
+	assert(m_initialized);
+
+	UINT16 data = 0xffff;
+
+	if (m_16bit_system)
+	{
+		data = m_mem->read_word(address);
+	}
+	else
+	{
+		data  = m_mem->read_byte(address);
+		data |= m_mem->read_byte(address + 1) << 8;
+	}
+
+	return data;
 }
 
 
@@ -70,12 +215,22 @@ WRITE_LINE_MEMBER( i8089_device::ca_w )
 {
 	if (VERBOSE)
 		logerror("%s('%s'): ca_w: %u\n", shortname(), basetag(), state);
+
+	if (m_ca == 1 && state == 0)
+	{
+		if (!m_initialized)
+			initialize();
+	}
+
+	m_ca = state;
 }
 
 WRITE_LINE_MEMBER( i8089_device::sel_w )
 {
 	if (VERBOSE)
 		logerror("%s('%s'): sel_w: %u\n", shortname(), basetag(), state);
+
+	m_sel = state;
 }
 
 WRITE_LINE_MEMBER( i8089_device::drq1_w )

src/emu/machine/i8089.h

@@ -18,7 +18,7 @@
 
 #define MCFG_I8089_ADD(_tag, _clock, _cputag) \
 	MCFG_DEVICE_ADD(_tag, I8089, _clock) \
-	i8089_device::static_set_cputag(*device, _cputag); \
+	i8089_device::static_set_cputag(*device, _cputag);
 
 #define MCFG_I8089_SINTR1(_sintr1) \
 	downcast<i8089_device *>(device)->set_sintr1_callback(DEVCB2_##_sintr1);
@@ -31,6 +31,9 @@
 //  TYPE DEFINITIONS
 //**************************************************************************
 
+// forward declaration
+class i8089_channel;
+
 // ======================> i8089_device
 
 class i8089_device : public device_t
@@ -59,12 +62,38 @@ protected:
 	virtual void device_start();
 	virtual void device_reset();
 
+	// optional information overrides
+	virtual machine_config_constructor device_mconfig_additions() const;
+
 private:
+	required_device<i8089_channel> m_ch1;
+	required_device<i8089_channel> m_ch2;
+
 	devcb2_write_line m_write_sintr1;
 	devcb2_write_line m_write_sintr2;
 
+	void initialize();
+	UINT16 read_word(offs_t address);
+
 	// internal state
 	const char *m_cputag;
+
+	address_space *m_mem;
+	address_space *m_io;
+
+	// system configuration
+	bool m_initialized;
+	bool m_16bit_system;
+	bool m_16bit_remote;
+	bool m_master;
+	bool m_request_grant;
+
+	// control block location
+	offs_t m_control_block;
+
+	// state of input pins
+	int m_ca;
+	int m_sel;
 };