Merge pull request #1627 from JoakimLarsson/z80dart

DART: Refactored FIFO:s using new template based fifo class

src/devices/machine/z80dart.cpp

@@ -31,21 +31,21 @@
 
 #include "z80dart.h"
 
-
-
 //**************************************************************************
 //  MACROS / CONSTANTS
 //**************************************************************************
 
 #define VERBOSE 0
+#define LOGPRINT(x) do { if (VERBOSE) logerror x; } while (0)
+#define LOG(x)      {} LOGPRINT(x)
 
-#define LOG(x) do { if (VERBOSE) logerror x; } while (0)
+#if VERBOSE == 2
+#define logerror printf
+#endif
 
 #define CHANA_TAG   "cha"
 #define CHANB_TAG   "chb"
 
-
-
 //**************************************************************************
 //  DEVICE DEFINITIONS
 //**************************************************************************
@@ -503,7 +503,6 @@ z80dart_channel::z80dart_channel(const machine_config &mconfig, const char *tag,
 	: device_t(mconfig, Z80DART_CHANNEL, "Z80 DART channel", tag, owner, clock, "z80dart_channel", __FILE__),
 		device_serial_interface(mconfig, *this),
 		m_rx_error(0),
-		m_rx_fifo(-1),
 		m_rx_clock(0),
 		m_rx_first(0),
 		m_rx_break(0),
@@ -523,12 +522,6 @@ z80dart_channel::z80dart_channel(const machine_config &mconfig, const char *tag,
 
 	for (auto & elem : m_wr)
 		elem = 0;
-
-	for (int i = 0; i < 3; i++)
-	{
-		m_rx_data_fifo[i] = 0;
-		m_rx_error_fifo[i] = 0;
-	}
 }
 
 
@@ -544,10 +537,8 @@ void z80dart_channel::device_start()
 	// state saving
 	save_item(NAME(m_rr));
 	save_item(NAME(m_wr));
-	save_item(NAME(m_rx_data_fifo));
+	//	save_item(NAME(m_rx_data_fifo));
-	save_item(NAME(m_rx_error_fifo));
+	//	save_item(NAME(m_rx_error_fifo));
-	save_item(NAME(m_rx_error));
-	save_item(NAME(m_rx_fifo));
 	save_item(NAME(m_rx_clock));
 	save_item(NAME(m_rx_first));
 	save_item(NAME(m_rx_break));
@@ -1001,18 +992,15 @@ uint8_t z80dart_channel::data_read()
 {
 	uint8_t data = 0;
 
-	if (m_rx_fifo >= 0)
+	if (!m_rx_data_fifo.empty())
 	{
 		// load data from the FIFO
-		data = m_rx_data_fifo[m_rx_fifo];
+		data = m_rx_data_fifo.dequeue();
 
 		// load error status from the FIFO
-		m_rr[1] = (m_rr[1] & ~(RR1_CRC_FRAMING_ERROR | RR1_RX_OVERRUN_ERROR | RR1_PARITY_ERROR)) | m_rx_error_fifo[m_rx_fifo];
+		m_rr[1] = (m_rr[1] & ~(RR1_CRC_FRAMING_ERROR | RR1_RX_OVERRUN_ERROR | RR1_PARITY_ERROR)) | m_rx_error_fifo.dequeue();
 
-		// decrease FIFO pointer
+		if (m_rx_data_fifo.empty())
-		m_rx_fifo--;
-
-		if (m_rx_fifo < 0)
 		{
 			// no more characters available in the FIFO
 			m_rr[0] &= ~ RR0_RX_CHAR_AVAILABLE;
@@ -1064,7 +1052,7 @@ void z80dart_channel::receive_data(uint8_t data)
 {
 	LOG(("Z80DART \"%s\" Channel %c : Receive Data Byte '%02x'\n", m_owner->tag(), 'A' + m_index, data));
 
-	if (m_rx_fifo == 2)
+	if (m_rx_data_fifo.full())
 	{
 		// receive overrun error detected
 		m_rx_error |= RR1_RX_OVERRUN_ERROR;
@@ -1083,15 +1071,16 @@ void z80dart_channel::receive_data(uint8_t data)
 			m_uart->trigger_interrupt(m_index, INT_SPECIAL);
 			break;
 		}
+		// overwrite last character/error with received character and error status into FIFO
+		m_rx_data_fifo.poke(data);
+		m_rx_error_fifo.poke(m_rx_error);
 	}
 	else
 	{
-		m_rx_fifo++;
-	}
-
 		// store received character and error status into FIFO
-	m_rx_data_fifo[m_rx_fifo] = data;
+		m_rx_data_fifo.enqueue(data);
-	m_rx_error_fifo[m_rx_fifo] = m_rx_error;
+		m_rx_error_fifo.enqueue(m_rx_error);
+	}
 
 	m_rr[0] |= RR0_RX_CHAR_AVAILABLE;
 

src/devices/machine/z80dart.h

@@ -428,11 +428,10 @@ protected:
 	int get_tx_word_length();
 
 	// receiver state
-	uint8_t m_rx_data_fifo[3];    // receive data FIFO
+	util::fifo<uint8_t, 3> m_rx_data_fifo;
-	uint8_t m_rx_error_fifo[3];   // receive error FIFO
+	util::fifo<uint8_t, 3> m_rx_error_fifo;
-	uint8_t m_rx_error;           // current receive error
-	int m_rx_fifo;              // receive FIFO pointer
 
+	uint8_t m_rx_error;           // current receive error
 	int m_rx_clock;             // receive clock pulse count
 	int m_rx_first;             // first character received
 	int m_rx_break;             // receive break condition

src/lib/util/coretmpl.h

@@ -428,7 +428,7 @@ public:
 	fifo()
 		: std::array<T, N>()
 		, m_head(this->begin())
-		, m_tail(this->end())
+		, m_tail(this->begin())
 		, m_empty(true)
 	{
 		static_assert(0U < N, "FIFO must have at least one element");
@@ -513,11 +513,28 @@ public:
 		return result;
 	}
 
+	void poke(T &v)
+	{
+		*m_tail = v;
+	}
+
+	void poke(T &&v)
+	{
+		*m_tail = std::move(v);
+	}
+
 	T const &peek() const
 	{
 		return *m_head;
 	}
 
+	void clear() const
+	{
+		m_head = m_tail = this->begin();
+		m_empty = true;
+		return *m_head;
+	}
+
 private:
 	typename fifo::iterator m_head, m_tail;
 	bool                    m_empty;