makeDetailsMask() special bits code (q10)

Explorer09 · Feb 13, 2024 · 45e913b · 45e913b
1 parent ec21942
commit 45e913b
Showing 1 changed file with 29 additions and 18 deletions.
diff --git a/Meter.c b/Meter.c
@@ -552,33 +552,44 @@ static uint16_t GraphMeterMode_makeDetailsMask(const GraphColorComputeState* pre
    uint16_t mask = 0xFFFF >> blanksAtStart;
    // See the code and comments of the "printCellDetails" function for how
    // special bits are used.
-   bool needsTiebreak = (blanksAtStart == blanksAtEnd && (mask & 0xDFFF) == 0x1FFF);
-   if (needsTiebreak && roundsUpInAscii)
-      mask &= 0xF7FF;
+   bool needsTiebreak = blanksAtStart >= 2 && blanksAtStart < 4 && blanksAtStart == blanksAtEnd;
 
-   if (new->nCellsPainted - prev->nCellsPainted == 1)
+   if (new->nCellsPainted - prev->nCellsPainted == 1) {
+      assert(blanksAtStart + blanksAtEnd < 8);
+      if (roundsUpInAscii && needsTiebreak) {
+         mask &= 0xF7FF;
+      }
       mask >>= 8;
+   } else if (roundsUpInAscii) {
+      if (blanksAtStart < 4 && (uint8_t)(blanksAtStart + blanksAtEnd % 4) >= 4) {
+         mask &= 0xF7FF;
+      }
+   }
 
    mask &= 0xFFFF << blanksAtEnd;
 
-   if (needsTiebreak) {
-      if (roundsUpInAscii) {
-         if (new->nCellsPainted - prev->nCellsPainted == 1) {
-            mask |= 0x0004;
-         }
-      } else if (roundsDownInAscii) {
+   if (roundsUpInAscii) {
+      if (needsTiebreak) {
+         mask |= 0x0004;
+      }
+   } else if (roundsDownInAscii) {
+      assert(blanksAtStart <= blanksAtEnd);
+      if (needsTiebreak) {
          mask = (mask & 0xFFEF) | 0x0020;
+      } else if (new->nCellsPainted - prev->nCellsPainted != 1) {
+         if (blanksAtEnd < 4 && (uint8_t)(blanksAtStart + blanksAtEnd) >= 4) {
+            mask = (mask & 0xFFEF) | 0x0020;
+         }
       }
-   } else if ((mask & 0xBFFD) == 0x1FFC) {
-      // 5 dots at start, 6 or 7 dots at end
-      assert(mask == 0x1FFC || mask == 0x1FFE);
-      mask &= 0xF7FF;
-   } else if ((mask & 0xBFFD) == 0x3FF8) {
-      // 6 or 7 dots at start, 5 dots at end
-      assert(mask == 0x3FF8 || mask == 0x7FF8);
-      mask &= 0xFFEF;
    }
 
+   // The following result values are impossible as they lack special bits
+   // needed for the ASCII display mode.
+   assert(mask != 0x3FF8); // Should be 0x37F8 or 0x3FE8
+   assert(mask != 0x7FF8); // Should be 0x77F8 or 0x7FE8
+   assert(mask != 0x1FFC); // Should be 0x17FC
+   assert(mask != 0x1FFE); // Should be 0x17FE
+
    return mask;
 }