1.37s -> 1.14s. Store 2 skips in 1 byte

Jumbub · Mar 20, 2022 · 07ca8c5 · 07ca8c5
1 parent 34755bb
commit 07ca8c5
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Showing 3 changed files with 26 additions and 21 deletions.
diff --git a/src/logic/board.h b/src/logic/board.h
@@ -6,9 +6,14 @@
 using uint = unsigned int;
 using ulong = unsigned long;
 using Cell = uint8_t;
+
 [[maybe_unused]] const Cell ALIVE = 1;
 [[maybe_unused]] const Cell DEAD = 0;
 
+[[maybe_unused]] const Cell SKIP_2 = (1 << 1) + (1 << 2);
+[[maybe_unused]] const Cell SKIP_1 = (1 << 2);
+[[maybe_unused]] const Cell SKIP_0 = 0;
+
 constexpr unsigned int PADDING = 2;  // Padding of board left+right or top+bottom.
 
 struct Board {

diff --git a/src/logic/next.cpp b/src/logic/next.cpp
@@ -16,8 +16,8 @@ constexpr uint8_t LOOKUP[20] = {
     0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0,
 };
 
-const uint64_t SKIP_EIGHT =
-    (1 << 0) + (1 << 8) + (1 << 16) + (1 << 24) + (1l << 32) + (1l << 40) + (1l << 48) + (1l << 56);
+const uint64_t SKIP_SIXTEEN = (SKIP_2 << 0) + (SKIP_2 << 8) + (SKIP_2 << 16) + (SKIP_2 << 24) + ((long)SKIP_2 << 32) +
+                              ((long)SKIP_2 << 40) + ((long)SKIP_2 << 48) + ((long)SKIP_2 << 56);
 
 uint isAlive(const uint& i, const Cell* input, const uint& realWidth) {
   const Cell* top = &input[i - realWidth - 1];
@@ -32,9 +32,9 @@ uint isAlive(const uint& i, const Cell* input, const uint& realWidth) {
 }
 
 inline void revokeSkipForNeighbours(const uint& i, Cell* skips, const uint& realWidth) {
-  *reinterpret_cast<uint32_t*>(&skips[i - realWidth - 1]) = false;
-  *reinterpret_cast<uint32_t*>(&skips[i - 1]) = false;
-  *reinterpret_cast<uint32_t*>(&skips[i + realWidth - 1]) = false;
+  *reinterpret_cast<uint32_t*>(&skips[(i - realWidth - 1) / 2]) = SKIP_0;
+  *reinterpret_cast<uint32_t*>(&skips[(i - 1) / 2]) = SKIP_0;
+  *reinterpret_cast<uint32_t*>(&skips[(i + realWidth - 1) / 2]) = SKIP_0;
 }
 
 void nextBoardSection(
@@ -46,8 +46,8 @@ void nextBoardSection(
     uint8_t* inSkip,
     uint8_t* outSkip) {
   while (i < endI) {
-    while (uint8s_to_uint64(&inSkip[i]) == SKIP_EIGHT)
-      i += 8;
+    while (uint8s_to_uint64(&inSkip[i / 2]) == SKIP_SIXTEEN)
+      i += 16;
 
     output[i] = isAlive(i, input, realWidth);
 
@@ -82,28 +82,28 @@ void nextBoard(Board& board, const uint& threadCount, const uint& jobCount) {
     const auto& beginI = std::get<0>(segments[i]);
     const auto& endI = std::get<1>(segments[i]);
 
-    board.inSkip[endI] = false;  // Never skip last cell
-
     // Reset next border
     if (i == jobCount - 1) {
-      std::memset(&board.outSkip[endI - board.rawWidth], true, board.rawSize - (endI - board.rawWidth));
+      std::memset(&board.outSkip[(endI - board.rawWidth) / 2], SKIP_2, (board.rawSize - (endI - board.rawWidth)) / 2);
     } else {
       const auto borderSize = std::min(board.rawSize, endI + board.rawWidth * 3);
-      std::memset(&board.outSkip[endI - board.rawWidth], true, borderSize - endI);
+      std::memset(&board.outSkip[endI - board.rawWidth], SKIP_2, (borderSize - endI) / 2);
     }
 
     jobs[i] = [&, beginI, endI]() {
       // Reset inner skips
       if (endI == beginI)
         return;
       const auto max = std::max(beginI + board.rawWidth, endI - board.rawWidth);
-      std::memset(&board.outSkip[beginI + board.rawWidth], true, max - beginI - board.rawWidth);
+      std::memset(&board.outSkip[(beginI + board.rawWidth) / 2], SKIP_2, (max - beginI - board.rawWidth) / 2);
       nextBoardSection(beginI + 1, endI - 1, board.rawWidth, board.input, board.output, board.inSkip, board.outSkip);
     };
+
+    board.inSkip[endI] = SKIP_0;  // Never skip last cell of segment
   };
 
   // Reset first border
-  std::memset(board.outSkip, true, sizeof(Cell) * board.rawWidth);
+  std::memset(board.outSkip, SKIP_2, (sizeof(Cell) * board.rawWidth) / 2);
 
   std::atomic<uint> job = {0};
   std::vector<std::thread> threads(threadCount - 1);

diff --git a/src/logic/padding.cpp b/src/logic/padding.cpp
@@ -28,21 +28,21 @@ void assignSkips(Cell* cells, uint innerWidth, uint innerHeight) {
   const uint height = innerHeight + PADDING;
 
   for (uint i = 1; i <= width - 1; i++) {
-    cells[i + width * innerHeight] = cells[i + width * innerHeight] & cells[i];
+    cells[(i + width * innerHeight) / 2] = SKIP_0;
   }
   for (uint i = width * (height - 1) + 1; i <= width * height - 2; i++) {
-    cells[i - width * innerHeight] = cells[i - width * innerHeight] & cells[i];
+    cells[(i - width * innerHeight) / 2] = SKIP_0;
   }
   for (uint i = width; i <= width * (height - 1); i += width) {
-    cells[i + innerWidth] = cells[i + innerWidth] & cells[i];
+    cells[(i + innerWidth) / 2] = SKIP_0;
   }
   for (uint i = (width * 2) - 1; i <= width * (height - 1) - 1; i += width) {
-    cells[i - innerWidth] = cells[i - innerWidth] & cells[i];
+    cells[(i - innerWidth) / 2] = SKIP_0;
   }
-  cells[0] = cells[0] & cells[width * (height - 1) - 2];
-  cells[width - 1] = cells[width - 1] & cells[width * (height - 2) + 1];
-  cells[width * (height - 1)] = cells[width * (height - 1)] & cells[width * 2 - 2];
-  cells[width * height - 1] = cells[width * height - 1] & cells[width + 1];
+  cells[(0) / 2] = SKIP_0;
+  cells[(width - 1) / 2] = SKIP_0;
+  cells[(width * (height - 1)) / 2] = SKIP_0;
+  cells[(width * height - 1) / 2] = SKIP_0;
 }
 
 void assignBoardPadding(Board& board) {