Bug fixes for hp9845c & remote488 (#6772)

* hp9845: fixed a graphic memory addressing bug (nw)

* remote488: fixed a signal corruption bug in IEEE488 remotizer (nw)

src/devices/bus/ieee488/remote488.cpp

@@ -487,32 +487,24 @@ void remote488_device::update_signals_from_rem(uint8_t to_set , uint8_t to_clear
 	m_in_signals |= to_set;
 	m_in_signals &= ~to_clear;
 	diff ^= m_in_signals;
-	m_out_signals = m_in_signals;
 
 	//LOG("REM SIG %02x %02x\n" , m_in_signals , diff);
 	m_no_propagation = true;
-	uint8_t tmp = m_out_signals;
 
 	if (BIT(diff , SIGNAL_ATN_BIT)) {
 		m_bus->atn_w(this , BIT(m_in_signals , SIGNAL_ATN_BIT));
-		COPY_BIT(m_bus->atn_r() , tmp , SIGNAL_ATN_BIT);
 	}
 	if (BIT(diff , SIGNAL_IFC_BIT)) {
 		m_bus->ifc_w(this , BIT(m_in_signals , SIGNAL_IFC_BIT));
-		COPY_BIT(m_bus->ifc_r() , tmp , SIGNAL_IFC_BIT);
 	}
 	if (BIT(diff , SIGNAL_REN_BIT)) {
 		m_bus->ren_w(this , BIT(m_in_signals , SIGNAL_REN_BIT));
-		COPY_BIT(m_bus->ren_r() , tmp , SIGNAL_REN_BIT);
 	}
 	if (BIT(diff , SIGNAL_SRQ_BIT)) {
 		m_bus->srq_w(this , BIT(m_in_signals , SIGNAL_SRQ_BIT));
-		COPY_BIT(m_bus->srq_r() , tmp , SIGNAL_SRQ_BIT);
 	}
 
 	m_no_propagation = false;
-
-	update_state(tmp);
 }
 
 void remote488_device::update_signal(signal_bit bit , int state)

src/mame/drivers/hp9845.cpp

@@ -1993,7 +1993,6 @@ private:
 	void graphic_video_render(unsigned video_scanline);
 	virtual void plot(uint16_t x, uint16_t y, bool draw_erase) override;
 
-	void check_io_counter_restore();
 	void advance_io_counter();
 	virtual void advance_gv_fsm(bool ds , bool trigger) override;
 	virtual void update_graphic_bits() override;
@@ -2012,7 +2011,6 @@ private:
 	uint16_t m_gv_music_memory;
 	uint8_t m_gv_cursor_color;
 	uint8_t m_gv_plane;
-	bool m_gv_plane_wrap;
 	bool m_gv_lp_int_latched;
 	bool m_gv_sk_int_latched;
 };
@@ -2076,7 +2074,6 @@ void hp9845c_state::machine_reset()
 	// TODO: correct?
 	m_gv_cursor_color = 7;
 	m_gv_plane = 0;
-	m_gv_plane_wrap = false;
 	m_gv_lp_int_latched = false;
 	m_gv_sk_int_latched = false;
 }
@@ -2402,21 +2399,6 @@ void hp9845c_state::plot(uint16_t x, uint16_t y, bool draw_erase)
 	}
 }
 
-void hp9845c_state::check_io_counter_restore()
-{
-	if (m_gv_last_cmd != m_gv_cmd) {
-		// restore memory counter
-		m_gv_io_counter = get_gv_mem_addr(m_gv_word_x_position , m_gv_word_y_position);
-		// no auto-increment when switching commands
-		if (m_gv_plane_wrap) {
-			m_gv_plane = 2;
-		} else if (m_gv_plane > 0) {
-			m_gv_plane--;
-		}
-		m_gv_last_cmd = m_gv_cmd;
-	}
-}
-
 void hp9845c_state::advance_io_counter()
 {
 	m_gv_plane++;
@@ -2427,7 +2409,6 @@ void hp9845c_state::advance_io_counter()
 		} else {
 			m_gv_plane = 2;
 		}
-		m_gv_plane_wrap = true;
 	}
 }
 
@@ -2450,22 +2431,18 @@ void hp9845c_state::advance_gv_fsm(bool ds , bool trigger)
 			// inital state (same as GV_STAT_RESET), command received
 			if (m_gv_cmd == 0x1) {
 				// read words command
-				check_io_counter_restore();
+				LOG("read words\n");
-				LOG("read words, last = %x\n", m_gv_last_cmd);
+				m_gv_fsm_state = GV_STAT_WAIT_TRIG_0;
-				m_gv_fsm_state = GV_STAT_WAIT_MEM_0;    // -> read stream
-				m_gv_last_cmd = m_gv_cmd;
 			} else if (ds) {
 				if ((m_gv_cmd == 0x0) || (m_gv_cmd == 0x2)) {
 					// write words & clear/set words commands
-					check_io_counter_restore();
+					if (m_gv_cmd == 0x2) LOG("clear/set words\n");
-					if (m_gv_cmd == 0x2) LOG("clear/set words, last = %x\n", m_gv_last_cmd);
+					else LOG("write words\n");
-					else LOG("write words, last = %x\n", m_gv_last_cmd);
 					m_gv_fsm_state = GV_STAT_WAIT_TRIG_1;   // -> write stream
 				} else {
 					// any other command
 					m_gv_fsm_state = GV_STAT_WAIT_TRIG_0;   // -> wait for trigger
 				}
-				m_gv_last_cmd = m_gv_cmd;
 			} else {
 				get_out = true;
 			}
@@ -2475,19 +2452,18 @@ void hp9845c_state::advance_gv_fsm(bool ds , bool trigger)
 			// process data on R4 or R6
 			if (act_trig) {
 				switch (m_gv_cmd) {
+				case 1:	// read words command
+					break;
 				case 0x8:   // load X I/O address
 					m_gv_word_x_position = ~m_gv_data_w & 0x3f;     // 0..34
 					LOG("load X I/O adress = %04x\n", m_gv_word_x_position);
 					m_gv_io_counter = get_gv_mem_addr(m_gv_word_x_position , m_gv_word_y_position);
 					m_gv_plane = 0;
-					m_gv_plane_wrap = false;
 					break;
 				case 0x9:   // load Y I/O address
 					m_gv_word_y_position = ~m_gv_data_w & 0x1ff;    // 0..454
 					LOG("load Y I/O adress = %04x\n", m_gv_word_y_position);
 					m_gv_io_counter = get_gv_mem_addr(m_gv_word_x_position , m_gv_word_y_position);
-					m_gv_plane = 0;
-					m_gv_plane_wrap = false;
 					break;
 				case 0xa:   // load memory control
 					m_gv_memory_control = m_gv_data_w & 0x7f;
@@ -2518,7 +2494,9 @@ void hp9845c_state::advance_gv_fsm(bool ds , bool trigger)
 				default:
 					logerror("unknown 98770A command = %d, parm = 0x%04x\n", m_gv_cmd, m_gv_data_w);
 				}
-				if (m_gv_cmd == 0xd) {
+				if (m_gv_cmd == 1) {	// Read words
+					m_gv_fsm_state = GV_STAT_WAIT_MEM_0;
+				} else if (m_gv_cmd == 0xd) {
 					m_gv_fsm_state = GV_STAT_WAIT_DS_2;     // -> get second data word
 				} else {
 					get_out = true;
@@ -2548,7 +2526,7 @@ void hp9845c_state::advance_gv_fsm(bool ds , bool trigger)
 			// wait for data word to be read
 			if (ds) {
 				// -- next word
-				m_gv_fsm_state = GV_STAT_WAIT_MEM_0;    // -> process data word
+				m_gv_fsm_state = GV_STAT_WAIT_TRIG_0;    // -> process data word
 			} else {
 				// -- done
 				get_out = true;