- simplified m_symbolMask calculation

- removed debug prints

git-svn-id: http://moon:8086/svn/software/trunk/libsrc/cpp@1083 b431acfa-c32f-4a4a-93f1-934dc6c82436

radio/DeSymbolizer.cpp

@@ -4,8 +4,6 @@
 #include <stdint.h>
 #include "DeSymbolizer.hpp"
 
-#define DESYMBOLIZER_DEBUG printf
-
 DeSymbolizer::DeSymbolizer()
 : Processor::Block(1, 1)
 , m_dataBitCount(0)
@@ -23,12 +21,7 @@ DeSymbolizer::DeSymbolizer()
 void DeSymbolizer::setNumBitsPerSymbol(size_t nBitsPerSym)
 {
 	m_nBitsPerSym = nBitsPerSym;
-	m_symbolMask = 0;
+	m_symbolMask = (1 << nBitsPerSym) - 1;
-	for(size_t k=0; k < nBitsPerSym; k++)
-	{
-		m_symbolMask <<= 1;
-		m_symbolMask |= 1;
-	}
 	m_dataBitCount = 0;
 	m_lastSymbol = 0;
 }
@@ -48,23 +41,20 @@ void DeSymbolizer::sync(symbol_t symbol)
 	{
 		m_sync_counter = 0;
 		m_sync_dist_last = 0;
-		DESYMBOLIZER_DEBUG("Idle -> ACQ\n");
 		m_state = State::Acq;
 	}
 	else if (m_state == State::Acq)
 	{
 		if (is_preamble(word))
 		{
-			DESYMBOLIZER_DEBUG("Acquired bit sync. Last bit sync was %zu symbols ago\n", m_sync_dist);
 			if (m_sync_dist_last == m_sync_dist)
 			{
 				m_sync_counter++;
-				DESYMBOLIZER_DEBUG("Received sync at %zu %zu times -> OK\n", m_sync_dist, m_sync_counter);
 				if (m_sync_counter == SYNC_COUNTER_RELOAD)
 				{
 					m_sync_counter = 0;
-					m_dataBitCount = 0;
+					// Adjust data count phase
-					DESYMBOLIZER_DEBUG("ACQ -> TRK\n");
+					m_dataBitCount = m_nBitsPerSym;
 					m_state = State::Trk;
 				}
 			}
@@ -83,54 +73,52 @@ void DeSymbolizer::sync(symbol_t symbol)
 		{
 			if (not is_preamble(word))
 			{			
-				DESYMBOLIZER_DEBUG("Missed sync at %zu. Found %04X instead -> NOK\n", m_sync_dist, word);
-				DESYMBOLIZER_DEBUG("TRK -> Idle\n");
 				m_state = State::Idle;
 			}
-			else
-			{
-//				printf("We tracked sync at %zu -> OK\n", m_sync_dist);
-			}
 			m_sync_dist = 0;
 		}
-		else
-		{
-			if (is_preamble(word))
-			{			
-				DESYMBOLIZER_DEBUG("Found sync at %zu -> IGN\n", m_sync_dist);
-			}
-		}
 	}
 	m_sync_dist++;
 }
 
-uint8_t DeSymbolizer::sym2byte(symbol_t symbol)
+size_t DeSymbolizer::sym2bytes(symbol_t symbol, uint8_t *pBytes)
 {
-	static uint8_t byte;
-	byte <<= m_nBitsPerSym;
-	byte |= symbol & m_symbolMask;
 
-	return byte;
+	static uint8_t byte;
+	size_t num_produced = 0;
+
+	// Transmission order MSB first
+	for (size_t i=0; i < m_nBitsPerSym; i++)
+	{
+		byte <<= 1;
+		byte |= (symbol_t)(symbol >> (m_nBitsPerSym-1) & 1);
+		symbol <<= 1;
+		m_dataBitCount--;
+		if (m_dataBitCount == 0)
+		{
+			pBytes[num_produced++] = byte;
+			m_dataBitCount = 8;
+		}
+	}
+	return num_produced;
 }
 
 void DeSymbolizer::process(symbol_t symbol_enc)
 {
-
+	uint8_t bytes[2];
 	symbol_t symbol = differentialDecode(symbol_enc);
 	sync(symbol);
 
 	// Create bytes from symbol
-	uint8_t byte = sym2byte(symbol);
+	size_t numBytes = sym2bytes(symbol, bytes);
 
 	// Commit bytes if in sync
 	if (m_state == State::Trk)
 	{
-		if (m_dataBitCount == 0)
+		if (numBytes)
 		{
-//			printf("Write %02X\n", byte);
+			m_buf_out->write(bytes, numBytes);
-			m_buf_out->write(&byte, 1);
 		}
-		m_dataBitCount = (m_dataBitCount + m_nBitsPerSym) & 7;
 	}
 }
 

radio/DeSymbolizer.hpp

@@ -30,8 +30,8 @@ public:
 
 
 private:
-	uint32_t m_nBitsPerSym;
+	size_t m_nBitsPerSym;
-	uint32_t m_dataBitCount;
+	size_t m_dataBitCount;
 	symbol_t m_lastSymbol;
 	symbol_t m_symbolMask;
 	symbol_t differentialDecode(symbol_t symbol);
@@ -45,7 +45,7 @@ private:
 	Processor::Buffer<uint8_t> *m_buf_out;
 	void process(symbol_t symbol);
 	void sync(symbol_t symbol);
-	uint8_t sym2byte(symbol_t symbol);
+	size_t sym2bytes(symbol_t symbol, uint8_t *pBytes);
 	bool is_preamble(uint16_t data);
 };