More topcat fixes (#3933)

* topcat: add has_changed() function (nw)

* topcat: don't write to plane if not enabled (nw)

* topcat: fix initialization order (nw)

src/devices/bus/hp_dio/hp98543.cpp

@@ -158,11 +158,20 @@ WRITE_LINE_MEMBER(dio16_98543_device::vblank_w)
 	for (auto &tc: m_topcat)
 		tc->vblank_w(state);
 }
+
 uint32_t dio16_98543_device::screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
 {
 	int startx[TOPCAT_COUNT], starty[TOPCAT_COUNT];
 	int endx[TOPCAT_COUNT], endy[TOPCAT_COUNT];
 
+	bool changed = false;
+
+	for (auto& tc: m_topcat)
+		changed |= tc->has_changed();
+
+	if (!changed)
+		return UPDATE_HAS_NOT_CHANGED;
+
 	for (int i = 0; i < TOPCAT_COUNT; i++)
 		m_topcat[i]->get_cursor_pos(startx[i], starty[i], endx[i], endy[i]);
 

src/devices/bus/hp_dio/hp98544.cpp

@@ -134,17 +134,26 @@ WRITE_LINE_MEMBER(dio16_98544_device::vblank_w)
 uint32_t dio16_98544_device::screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
 {
 	int startx, starty, endx, endy;
-	m_topcat->get_cursor_pos(startx, starty, endx, endy);
+
+
+	if (!m_topcat->has_changed())
+		return UPDATE_HAS_NOT_CHANGED;
 
 	for (int y = 0; y < m_v_pix; y++) {
 		uint32_t *scanline = &bitmap.pix32(y);
-		for (int x = 0; x < 1024; x++) {
+		for (int x = 0; x < m_h_pix; x++) {
 			uint8_t tmp = m_vram[y * m_h_pix + x];
-			if (y >= starty && y <= endy && x >= startx && x <= endx)
-				tmp |= 0xff;
 			*scanline++ = tmp ? rgb_t(255,255,255) : rgb_t(0, 0, 0);
 		}
 	}
+
+	m_topcat->get_cursor_pos(startx, starty, endx, endy);
+
+	for(int y = starty; y <= endy; y++) {
+		uint32_t *scanline = &bitmap.pix32(y);
+		memset(scanline + startx, 0xff, (endx - startx) << 2);
+	}
+
 	return 0;
 }
 

src/devices/video/topcat.cpp

@@ -53,6 +53,8 @@ void topcat_device::device_start()
 	save_item(NAME(m_fb_enable));
 	save_item(NAME(m_unknown_reg4a));
 	save_item(NAME(m_unknown_reg4c));
+	save_item(NAME(m_cursor_state));
+	save_item(NAME(m_changed));
 }
 
 //-------------------------------------------------
@@ -80,19 +82,21 @@ READ16_MEMBER(topcat_device::vram_r)
 
 WRITE16_MEMBER(topcat_device::vram_w)
 {
-	if (mem_mask & m_plane_mask) {
+	if (mem_mask & m_plane_mask && (m_fb_write_enable & (m_plane_mask << 8))) {
 		bool src = data & m_plane_mask;
 		bool dst = m_vram[offset * 2 + 1] & m_plane_mask;
 		execute_rule(src, (replacement_rule_t)((m_pixel_replacement_rule >> 8) & 0x0f), dst);
 		modify_vram_offset(offset * 2 + 1, dst);
 	}
 
-	if (mem_mask & (m_plane_mask << 8)) {
+	if (mem_mask & (m_plane_mask << 8) && (m_fb_write_enable & (m_plane_mask << 8))) {
 		bool src = data & (m_plane_mask << 8);
 		bool dst = m_vram[offset * 2] & m_plane_mask;
 		execute_rule(src, (replacement_rule_t)((m_pixel_replacement_rule >> 8) & 0x0f), dst);
 		modify_vram_offset(offset * 2, dst);
 	}
+
+	m_changed = true;
 }
 
 void topcat_device::get_cursor_pos(int &startx, int &starty, int &endx, int &endy)
@@ -103,10 +107,10 @@ void topcat_device::get_cursor_pos(int &startx, int &starty, int &endx, int &end
 		endx = m_cursor_x_pos + m_cursor_width;
 		endy = m_cursor_y_pos;
 	} else {
-		startx = 0;
+		startx = -1;
-		starty = 0;
+		starty = -1;
-		endx = 0;
+		endx = -1;
-		endy = 0;
+		endy = -1;
 	}
 }
 
@@ -114,6 +118,7 @@ TIMER_CALLBACK_MEMBER(topcat_device::cursor_callback)
 {
 	m_cursor_timer->adjust(attotime::from_hz(5));
 	m_cursor_state ^= true;
+	m_changed = true;
 }
 
 void topcat_device::update_cursor(int x, int y, uint16_t ctrl, uint8_t width)
@@ -347,6 +352,7 @@ WRITE16_MEMBER(topcat_device::ctrl_w)
 	if (!m_write_enable)
 		return;
 
+	m_changed = true;
 	switch (offset) {
 	case TOPCAT_REG_VBLANK:
 		m_vblank = data;

src/devices/video/topcat.h

@@ -20,12 +20,11 @@
 class topcat_device : public device_t
 {
 public:
-
 	template <class Object> devcb_base& set_int_write_cb(Object &&cb)
 	{ return m_int_write_func.set_callback(std::forward<Object>(cb)); }
 
 	topcat_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
-
+	bool has_changed() { bool ret = m_changed; m_changed = false; return ret; };
 	void set_fb_width(int _pixels) { m_fb_width = _pixels; }
 	void set_fb_height(int _pixels) { m_fb_height = _pixels; }
 	void set_planemask(int _mask) { m_plane_mask = _mask; }
@@ -157,6 +156,7 @@ private:
 	bool m_read_enable;
 	bool m_write_enable;
 	bool m_fb_enable;
+	bool m_changed;
 
 	required_shared_ptr<uint8_t> m_vram;
 };