floppy: Filter out the writes when write protected, useful when when the apple2gs does a packet send (e.g a write) over DCD with write protect forced on (to avoid damaging a possibly present disk).

src/devices/imagedev/floppy.cpp

@@ -954,10 +954,21 @@ attotime floppy_image_device::get_next_transition(const attotime &from_when)
 	}
 }
 
+bool floppy_image_device::writing_disabled() const
+{
+	// Disable writing when write protect is on or when, in the diskii
+	// case, phase 1 is 1
+	return wpt || (phases & 2);
+}
+
 void floppy_image_device::write_flux(const attotime &start, const attotime &end, int transition_count, const attotime *transitions)
 {
 	if(!image || mon)
 		return;
+
+	if(writing_disabled())
+		return;
+
 	image_dirty = true;
 	cache_clear();
 
@@ -2418,6 +2429,11 @@ void mac_floppy_device::device_reset()
 //    1110 - HD-20 drive
 //    1111 - No drive (pull-up on the sense line)
 
+bool mac_floppy_device::writing_disabled() const
+{
+	return wpt;
+}
+
 bool mac_floppy_device::wpt_r()
 {
 	static const char *const regnames[16] = {

src/devices/imagedev/floppy.h

@@ -96,7 +96,8 @@ public:
 	void setup_led_cb(led_cb cb);
 
 	std::vector<uint32_t> &get_buffer() { return image->get_buffer(cyl, ss, subcyl); }
-	int get_cyl() { return cyl; }
+	int get_cyl() const { return cyl; }
+	bool on_track() const { return !subcyl; }
 
 	virtual void mon_w(int state);
 	bool ready_r();
@@ -111,6 +112,8 @@ public:
 	bool ss_r() { return ss; }
 	bool twosid_r();
 
+	virtual bool writing_disabled() const;
+
 	virtual void seek_phase_w(int phases);
 	void stp_w(int state);
 	void dir_w(int state) { dir = state; }
@@ -285,6 +288,7 @@ public:
 	virtual void mon_w(int) override;
 	virtual void seek_phase_w(int phases) override;
 	virtual const char *image_interface() const noexcept override { return "floppy_3_5"; }
+	virtual bool writing_disabled() const override;
 
 protected:
 	u8 m_reg;

src/devices/machine/iwm.cpp

@@ -100,9 +100,6 @@ void iwm_device::set_floppy(floppy_image_device *floppy)
 
 	sync();
 
-	if(floppy && std::string(floppy->tag()) == ":fdc:0:525")
-		machine().debug_break();
-
 	logerror("floppy %s\n", floppy ? floppy->tag() : "-");
 
 	if(m_floppy && (m_control & 0x10))