diff --git a/edlib/src/edlib.cpp b/edlib/src/edlib.cpp
index e19f119..76625e8 100644
--- a/edlib/src/edlib.cpp
+++ b/edlib/src/edlib.cpp
@@ -401,46 +401,45 @@ static inline unsigned char* createReverseCopy(const unsigned char* const seq, c
  * @param [in] Pv  Bitset, Pv[i] == 1 if vin is +1, otherwise Pv[i] == 0.
  * @param [in] Mv  Bitset, Mv[i] == 1 if vin is -1, otherwise Mv[i] == 0.
  * @param [in] Eq  Bitset, Eq[i] == 1 if match, 0 if mismatch.
- * @param [in] hin  Will be +1, 0 or -1.
+ * @param [in] Phin  Bitset, 00..01 when hin == +1.
+ * @param [in] Mhin  Bitset, 00..01 when hin == -1.
  * @param [out] PvOut  Bitset, PvOut[i] == 1 if vout is +1, otherwise PvOut[i] == 0.
  * @param [out] MvOut  Bitset, MvOut[i] == 1 if vout is -1, otherwise MvOut[i] == 0.
- * @param [out] hout  Will be +1, 0 or -1.
+ * @param [out] Phout  Bitset, 00..01 when hout == +1.
+ * @param [out] Mhout  Bitset, 00..01 when hout == -1.
  */
-static inline int calculateBlock(Word Pv, Word Mv, Word Eq, const int hin,
+static inline pair<Word, Word> calculateBlock(Word Pv, Word Mv, Word Eq, const Word Phin, const Word Mhin,
                                  Word &PvOut, Word &MvOut) {
     // hin can be 1, -1 or 0.
     // 1  -> 00...01
     // 0  -> 00...00
     // -1 -> 11...11 (2-complement)
 
-    Word hinIsNeg = static_cast<Word>(hin >> 2) & WORD_1; // 00...001 if hin is -1, 00...000 if 0 or 1
-
     Word Xv = Eq | Mv;
     // This is instruction below written using 'if': if (hin < 0) Eq |= (Word)1;
-    Eq |= hinIsNeg;
+    Eq |= Mhin;
     Word Xh = (((Eq & Pv) + Pv) ^ Pv) | Eq;
 
     Word Ph = Mv | ~(Xh | Pv);
     Word Mh = Pv & Xh;
 
-    int hout = 0;
     // This is instruction below written using 'if': if (Ph & HIGH_BIT_MASK) hout = 1;
-    hout = (Ph & HIGH_BIT_MASK) >> (WORD_SIZE - 1);
+    Word Phout = Ph >> (WORD_SIZE - 1);
     // This is instruction below written using 'if': if (Mh & HIGH_BIT_MASK) hout = -1;
-    hout -= (Mh & HIGH_BIT_MASK) >> (WORD_SIZE - 1);
+    Word Mhout = Mh >> (WORD_SIZE - 1);
 
     Ph <<= 1;
     Mh <<= 1;
 
     // This is instruction below written using 'if': if (hin < 0) Mh |= (Word)1;
-    Mh |= hinIsNeg;
+    Mh |= Mhin;
     // This is instruction below written using 'if': if (hin > 0) Ph |= (Word)1;
-    Ph |= static_cast<Word>((hin + 1) >> 1);
+    Ph |= Phin;
 
     PvOut = Mh | ~(Xv | Ph);
     MvOut = Ph & Xv;
 
-    return hout;
+    return {Phout, Mhout};
 }
 
 /**
@@ -581,17 +580,22 @@ static int myersCalcEditDistanceSemiGlobal(
 
     int bestScore = -1;
     vector<int> positions; // TODO: Maybe put this on heap?
-    const int startHout = mode == EDLIB_MODE_HW ? 0 : 1; // If 0 then gap before query is not penalized;
+    const Word PstartHout = mode == EDLIB_MODE_HW ? 0 : 1; // If 0 then gap before query is not penalized;
     const unsigned char* targetChar = target;
     for (int c = 0; c < targetLength; c++) { // for each column
         const Word* Peq_c = Peq + (*targetChar) * maxNumBlocks;
 
         //----------------------- Calculate column -------------------------//
-        int hout = startHout;
+        Word Phout = PstartHout;
+        Word Mhout = 0;
+        int hout = 0;
         bl = blocks + firstBlock;
         Peq_c += firstBlock;
         for (int b = firstBlock; b <= lastBlock; b++) {
-            hout = calculateBlock(bl->P, bl->M, *Peq_c, hout, bl->P, bl->M);
+            pair<Word,Word> PMhout = calculateBlock(bl->P, bl->M, *Peq_c, Phout, Mhout, bl->P, bl->M);
+            Phout = PMhout.first;
+            Mhout = PMhout.second;
+            hout = Phout - Mhout;
             bl->score += hout;
             bl++; Peq_c++;
         }
@@ -605,7 +609,8 @@ static int myersCalcEditDistanceSemiGlobal(
             lastBlock++; bl++; Peq_c++;
             bl->P = static_cast<Word>(-1); // All 1s
             bl->M = static_cast<Word>(0);
-            bl->score = (bl - 1)->score - hout + WORD_SIZE + calculateBlock(bl->P, bl->M, *Peq_c, hout, bl->P, bl->M);
+            pair<Word, Word> PMhout = calculateBlock(bl->P, bl->M, *Peq_c, Phout, Mhout, bl->P, bl->M);
+            bl->score = (bl - 1)->score - hout + WORD_SIZE + PMhout.first - PMhout.second;
         } else {
             while (lastBlock >= firstBlock && bl->score >= k + WORD_SIZE) {
                 lastBlock--; bl--; Peq_c--;
@@ -780,9 +785,14 @@ static int myersCalcEditDistanceNW(const Word* const Peq, const int W, const int
 
         //----------------------- Calculate column -------------------------//
         int hout = 1;
+        Word Phout = 1;
+        Word Mhout = 0;
         bl = blocks + firstBlock;
         for (int b = firstBlock; b <= lastBlock; b++) {
-            hout = calculateBlock(bl->P, bl->M, Peq_c[b], hout, bl->P, bl->M);
+            pair<Word, Word> PMhout = calculateBlock(bl->P, bl->M, Peq_c[b], Phout, Mhout, bl->P, bl->M);
+            Phout = PMhout.first;
+            Mhout = PMhout.second;
+            hout = Phout - Mhout;
             bl->score += hout;
             bl++;
         }
@@ -806,7 +816,10 @@ static int myersCalcEditDistanceNW(const Word* const Peq, const int W, const int
             lastBlock++; bl++;
             bl->P = static_cast<Word>(-1); // All 1s
             bl->M = static_cast<Word>(0);
-            int newHout = calculateBlock(bl->P, bl->M, Peq_c[lastBlock], hout, bl->P, bl->M);
+            pair<Word, Word> PMhout = calculateBlock(bl->P, bl->M, Peq_c[lastBlock], Phout, Mhout, bl->P, bl->M);
+            Phout = PMhout.first;
+            Mhout = PMhout.second;
+            int newHout = Phout - Mhout;
             bl->score = (bl - 1)->score - hout + WORD_SIZE + newHout;
             hout = newHout;
         }