wd1010: expand head selection

src/devices/bus/apricot/expansion/winchester.cpp

@@ -170,6 +170,7 @@ WRITE_LINE_MEMBER( apricot_winchester_device::head_w )
 {
 	m_head = (m_head & ~(1 << N)) | (state << N);
 	LOGREGS("Select head: %d\n", m_head);
+	m_hdc->head_w(m_head);
 }
 
 template<int N>

src/devices/machine/wd1010.cpp

@@ -112,6 +112,7 @@ void wd1010_device::device_start()
 	save_item(NAME(m_cylinder));
 	save_item(NAME(m_sdh));
 	save_item(NAME(m_status));
+	save_item(NAME(m_head));
 }
 
 //-------------------------------------------------
@@ -332,6 +333,14 @@ void wd1010_device::brdy_w(int state)
 	m_brdy = state;
 }
 
+void wd1010_device::sc_w(int state)
+{
+	if (state)
+		m_status |= STATUS_SC;
+	else
+		m_status &= ~STATUS_SC;
+}
+
 int wd1010_device::sc_r()
 {
 	return m_status & STATUS_SC ? 1 : 0;

src/devices/machine/wd1010.h

@@ -40,11 +40,16 @@ public:
 
 	void drdy_w(int state);
 	void brdy_w(int state);
+	void sc_w(int state);
 
 	// actually inputs to the controller from the drive
 	int sc_r();
 	int tk000_r();
 
+	// HACK: head selection is not actually controlled by the wd1010, but this emulation currently
+	// works as if it does; this function allows heads beyond the 3-bit range of the sdh register.
+	void head_w(uint8_t head) { m_head = head; }
+
 protected:
 	// device-level overrides
 	virtual void device_start() override;
@@ -102,7 +107,7 @@ private:
 	int get_lbasector();
 
 	// extract values from sdh
-	int head() { return (m_sdh >> 0) & 0x07; }
+	int head() { return m_head; }
 	int drive() { return (m_sdh >> 3) & 0x03; }
 	int sector_size()
 	{
@@ -151,6 +156,7 @@ private:
 	uint16_t m_cylinder;
 	uint8_t m_sdh;
 	uint8_t m_status;
+	uint8_t m_head;
 };
 
 // device type definition

src/mame/drivers/unixpc.cpp

@@ -260,7 +260,8 @@ void unixpc_state::disk_control_w(uint8_t data)
 {
 	logerror("disk_control_w: %02x\n", data);
 
-	// TODO: bits 0-2 = head select
+	// bits 0-2 = head select
+	m_hdc->head_w(BIT(data, 0, 2));
 
 	m_hdc->drdy_w(BIT(data, 3) && m_hdr0->exists());