[swt] Check the SWT header for the word sequence and drop duplicate words

Author: kostorr

src/Swt/Swt.cxx

@@ -53,6 +53,7 @@ void Swt::reset()
 {
   barWrite(sc_regs::SC_RESET.index, 0x1);
   barWrite(sc_regs::SC_RESET.index, 0x0); //void cmd to sync clocks
+  mWordSequence = -1;
 }
 
 void Swt::read(std::vector<SwtWord>& words, TimeOut msTimeOut, SwtWord::Size wordSize)
@@ -84,6 +85,17 @@ void Swt::read(std::vector<SwtWord>& words, TimeOut msTimeOut, SwtWord::Size wor
     }
     tempWord.setHigh(barRead(sc_regs::SWT_RD_WORD_H.index));
 
+    mWordSequence = (mWordSequence + 1) % 16;
+
+    // If we get the same counter as before it means the FIFO wasn't updated; drop the word
+    if (tempWord.getSequence() != mWordSequence) { //TODO: Need to reproduce so that I can test!
+      getWarningLogger() << "SWT word sequence duplicate" << endm;
+
+      mWordSequence = tempWord.getSequence(); //roll mWordSequence back by one
+      numWords++;                             //will have to read one more time
+      continue;
+    }
+
     //wordMonPairs.push_back(std::make_pair(tempWord, barRead(sc_regs::SWT_MON.index)));
     words.push_back(tempWord);
   }

src/Swt/Swt.h

@@ -67,6 +67,7 @@ class Swt
   roc::RegisterReadWriteInterface& mBar2;
 
   AlfLink mLink;
+  int mWordSequence = -1;
 };
 
 } // namespace Alf

src/Swt/SwtWord.cxx

@@ -76,6 +76,7 @@ void SwtWord::setMed(uint32_t med)
 void SwtWord::setHigh(uint16_t high)
 {
   mHigh = high & 0xfff;
+  mSequence = (high & 0xf000) >> 12;
 }
 
 uint32_t SwtWord::getLow() const
@@ -93,6 +94,11 @@ uint16_t SwtWord::getHigh() const
   return mHigh & 0xfff;
 }
 
+int SwtWord::getSequence() const
+{
+  return mSequence;
+}
+
 std::ostream& operator<<(std::ostream& output, const SwtWord& swtWord)
 {
   output << "0x" << std::setfill('0') << std::hex << std::setw(3) << swtWord.getHigh()

src/Swt/SwtWord.h

@@ -46,6 +46,7 @@ class SwtWord
   uint32_t getLow() const;
   uint32_t getMed() const;
   uint16_t getHigh() const;
+  int getSequence() const;
 
   enum Size {
     High,
@@ -57,6 +58,7 @@ class SwtWord
   uint32_t mLow;
   uint32_t mMed;
   uint16_t mHigh;
+  int mSequence;
 };
 
 std::ostream& operator<<(std::ostream& output, const SwtWord& swtWord);